‘In individuals, insanity is rare, but in groups, parties, nations and epochs, it is the rule.’

– Michael Foucault

Foucault was a French philosopher and social theorist who wrote extensively on the history of Western thought, power and knowledge. In his book Madness and Civilization, Foucault views the treatment of the mentally ill in Western society as something that is shaped by historical, political, and cultural forces, malleable to changes over time. For instance, in the Middle Ages, madness was seen as a spiritual issue and was often associated with religious devotion. In the 17th and 18th centuries, however, the concept of madness became more medicalised and was seen as a physical illness. As a result, the insane were locked away in asylums and subjected to harsh treatment in the name of curing their illness. The effort to classify mental illness in the late 19th and early 20th centuries was seen as a part of a broader movement to professionalise and modernise psychiatry. The quote above highlights Foucault’s central argument that the way mental illness is defined and treated is shaped by the values and interests of the dominant cultural, economic and political forces of the time.

Appreciating the ethical and pragmatic challenges that come with classifying mental illness is as important as knowing the ins and outs of our classifications.

The ICD-11

The International Classification of Diseases is an international standard for diagnosing all medical conditions, including psychiatric disorders. The latest version, ICD-11, was published in 2018 and is used globally. There are 55000 unique codes for injuries, diseases, and causes of death in the ICD-11. For the purposes of the exam, we will go through the major diagnoses in Chapter 06 of the ICD-11, aptly named ‘Mental, behavioural, or Neurodevelopmental disorders’. There will still be diagnoses that exist outside of Chapter 06 that will be relevant in psychiatry, which are still included in the list below.

Neurodevelopmental disease

Disorders of intellectual development

Characterised by significantly below average intellectual functioning and adaptive behaviour (which refers to the set of conceptual, social, and practical skills) that are approximately ≥2 standard deviations below the mean in standardised tests. They are categorised as:

• Mild – 2-3 standard deviations.
• Moderate – 3-4 standard deviations.
• Severe – 4 or more standard deviations (may acquire basic self-care skills).
• Profound – 4 or more standard deviations (basic concrete skills).

They may manifest in the first days and months of life, in older children, late adolescence, or adulthood.

Developmental speech or language disorders

Speech/language difficulties occur during the early developmental period.

Subcategorised into:

• Developmental speech sound disorder (errors of pronunciation).
• Developmental speech fluency disorder (disruption of the normal rhythmic flow and rate of speech).
• Developmental language disorder (persistent difficulties in the acquisition, understanding, production or use of language.).
  • With impairment of receptive and expressive language (difficulties with producing and understanding spoken or signed language).
  • With impairment of mainly expressive language (difficulties with producing and using spoken or signed language but can still understand it).
  • With impairment of mainly pragmatic language (difficulties with the understanding and use of language in social contexts, for example, making inferences, understanding verbal humour, and resolving ambiguous meaning).

Autism spectrum disorder

Characterised by persistent deficits in the ability to initiate and to sustain reciprocal social interaction and social communication and by a range of restricted, repetitive, and inflexible patterns of behaviour, interests or activities that are clearly atypical or excessive for the individual’s age and sociocultural context.

• Though it presents clinically at all ages, including during adulthood, it is a lifelong disorder.
• Restricted and repetitive behaviours persist over time. Specifically, repetitive sensorimotor behaviours appear to be common, consistent, and potentially severe. During the school age years and adolescence, these repetitive sensorimotor behaviours begin to lessen in intensity and number. Insistence on sameness, which is less prevalent, appears to develop during preschool and worsen over time.
• Prevalence M>F 4:1.
• Females diagnosed with autism spectrum disorder are more frequently diagnosed with co-occurring disorders of intellectual development, suggesting that less severe presentations may go undetected as compared to males. Females tend to demonstrate fewer restricted, repetitive interests and behaviours than males.
• During middle-childhood, gender differences in presentation differentially affect functioning. Boys may act out with reactive aggression or other behavioural symptoms when challenged or frustrated. Girls tend to withdraw socially and react with emotional changes to their social adjustment difficulties.

Developmental learning disorder

Characterised by significant and persistent difficulties in learning academic skills, which may include reading, writing, or arithmetic. The individual’s performance in the affected academic skill(s) is markedly below what would be expected for chronological age and general level of intellectual functioning, resulting in significant impairment in the individual’s academic or occupational functioning.

Developmental motor coordination disorder

Characterised by a significant delay in the acquisition of gross and fine motor skills and impairment in the execution of coordinated motor skills that manifest in clumsiness, slowness, or inaccuracy of motor performance.

• Not made before age <5 due to variability in motor development in childhood.
• M>F 2:1 to 7:1.

Attention deficit hyperactivity disorder

Characterised by a persistent pattern (>6 months) of inattention and /or hyperactivity-impulsivity that has a direct negative impact on academic, occupational, or social functioning. There is evidence of significant inattention and/or hyperactivity-impulsivity symptoms prior to age 12, typically by early to mid-childhood, though some individuals may first come to clinical attention later.

• Subcategorised into – Predominantly inattentive presentation, predominantly hyperactive-impulsive presentation, or combined presentation.
• M>F (Ratio hotly debated.)
• Females are likelier to exhibit inattentive symptoms, whereas males are likelier to exhibit hyperactivity and impulsivity symptoms, particularly at younger ages.

Stereotyped movement disorder

Characterised by the persistent (e.g., lasting several months) presence of voluntary, repetitive, stereotyped, apparently purposeless (and often rhythmic) movements that arise during the early developmental period.

• Subcategorised into – With or without self-injury.
• Body-focused repetitive behaviour disorders (i.e., Trichotillomania and excoriation disorder) are characterised by recurrent and habitual behaviours directed at the integument (e.g., hair and skin). In contrast, stereotyped movements in stereotyped movement disorder rarely include hair-pulling or skin-picking behaviour, but if they do, the behaviour tends to be composed of coordinated movements that are patterned and predictable, utilising the same muscle groups in a particular sequence to produce the behaviour. In addition, stereotyped movements are more likely to present very early in life (i.e., <2 years of age), whereas body-focused repetitive behaviour disorders typically have an onset in later childhood or early adolescence.
• In contrast to tic disorders, including Tourette syndrome, stereotyped movements in stereotyped movement disorder tend to be composed of coordinated movements that are patterned and predictable and can be interrupted with distraction. Stereotyped movement disorder is further differentiated from tics and Tourette syndrome because the symptoms tend to emerge at a younger age, last longer than typical tics, lack a premonitory sensory urge, and may be experienced as enjoyable.

Primary tics or tic disorders

Characterised by the presence of chronic motor and/or vocal (phonic) tics. Motor and vocal tics are defined as sudden, rapid, non-rhythmic, and recurrent movements or vocalisations, respectively. Tourette syndrome is a chronic tic disorder characterised by the presence of both chronic motor tics and vocal (phonic) tics, with onset during the developmental period.

• In order to be diagnosed, tics must have been present >1 year.
• Although tics (both complex and simple) are preceded by premonitory sensory urges, which may diminish over time, tics are not aimed at neutralising antecedent cognitions (e.g., obsessions) or reducing physiological arousal (e.g. anxiety). If they are, this is more in keeping with OCD.
• Repetitive and stereotyped motor movements such as whole-body movements (e.g., rocking) and unusual hand or finger movements can be a characteristic feature of autism spectrum disorder and of stereotyped movement disorder. These behaviours can appear similar to tics but are differentiated because they tend to be more stereotyped, last longer than the duration of a typical tic, tend to emerge at a younger age, are not characterised by premonitory sensory urges, are often experienced by the individual as soothing or rewarding, and can generally be interrupted with distraction.

Schizophrenia and other primary psychotic disorders

Schizophrenia

Characterised by disturbances in multiple mental modalities, including thinking (e.g., delusions, disorganisation in the form of thought), perception (e.g., hallucinations), self-experience (e.g., the experience that one’s feelings, impulses, thoughts, or behaviour are under the control of an external force), cognition (e.g., impaired attention, verbal memory, and social cognition), volition (e.g., loss of motivation), affect (e.g., blunted emotional expression), and behaviour (e.g., behaviour that appears bizarre or purposeless, unpredictable or inappropriate emotional responses that interfere with the organisation of behaviour).

• ≥ 2 features must be present ≥ 1 month and ≥ 1 feature from 1. through 4.
  1. Delusions.
  2. Hallucinations.
  3. Formal thought disorders.
  4. Experiences of influence, passivity, and control.
  5. Negative symptoms – Flat affect, alogia, avolition, anhedonia.
  6. Disorganised behaviour that impedes goal-directed activity.
  7. Psychomotor disturbances – Catatonic restlessness/agitation, posturing, waxy flexibility, negativism, mutism, stupor.
• ICD-11 has now removed subtypes of schizophrenia found in previous versions of ICD: i.e., paranoid, hebephrenic, catatonic, and undifferentiated schizophrenia.
• Subcategorised into first episode (first manifestation of schizophrenia), multiple episodes (≥ 2 episodes with >3 months of partial/full remission in between), or continuous.
• Each of these subcategories are applied an additional specifier – Currently symptomatic (symptoms currently met or last met within the past 1 month) or, partial remission (some clinically significant features remain) or full remission (no clinically significant features remain).
• M>F. First psychotic episodes M: early to mid 20s. F: late 20s.

Schizoaffective disorder

An episodic disorder in which the diagnostic requirements of schizophrenia and a manic, mixed, or moderate or severe depressive episode are met within the same episode of illness, either simultaneously or within a few days of each other.

• Symptoms ≥1 month for both psychotic and mood symptoms.
• Subcategorised into first episode (first manifestation of schizoaffective disorder), multiple (≥ 2 episodes with >3 months of partial/full remission in between) or continuous.
• Each of these subcategories are applied a specifier, including currently symptomatic (symptoms currently met or last met within the past 1 month), partial remission (some clinically significant features remain) or full remission (no clinically significant features remain).
• F>M.

Schizotypal disorder

Characterised by an enduring pattern (≥2 years) of unusual speech, perceptions, beliefs and behaviours that are not of sufficient intensity or duration to meet the diagnostic requirements of schizophrenia, schizoaffective disorder, or delusional disorder. The pattern includes several of the following symptoms:

• Constricted affect, such that the individual appears cold and aloof.
• Behaviour or appearance that is odd, eccentric, unusual, or peculiar and is inconsistent with cultural or subcultural norms.
• Poor rapport with others and a tendency towards social withdrawal.
• Unusual beliefs or magical thinking influencing the person’s behaviour in ways that are inconsistent with subcultural norms but not reaching the diagnostic requirements for a delusion.
• Unusual perceptual distortions such as intense illusions, depersonalisation, derealisation, or auditory or other hallucinations.
• Suspiciousness or paranoid ideas.
• Vague, circumstantial, metaphorical, over-elaborate, or stereotyped thinking, manifest in odd speech without gross incoherence.
• Obsessive ruminations without a sense that the obsession is foreign or unwanted, often with body dysmorphic, sexual, or aggressive content.

Acute and transient psychotic disorder

Characterised by acute onset of psychotic symptoms that emerge without a prodrome and reach their maximal severity within 2 weeks.

• Duration ≤ 3 months, and most commonly lasts from a few days to 1 month.
• If symptoms are>3 months, a different diagnosis should be considered.
• Absence of negative symptoms during the episode.
• Subcategorised into first episode (first manifestation of AATPD) or multiple episodes (at least 2 episodes with >3 months of partial/full remission in between).
• Each of these subcategories are applied a specifier, including currently symptomatic (symptoms currently met or last met within the past 1 month) or, partial remission (some clinically significant features remain) or full remission (no clinically significant features remain).

Delusional disorder

Presence of a delusion or set of related delusions, typically persisting for >3 months and often much longer, in the absence of a depressive, manic or mixed episode.

Absence of clear positive symptoms or negative symptoms characteristic of schizophrenia. However, in some cases, specific hallucinations typically related to the content of the delusions may be present (e.g., tactile hallucinations in delusions of being infected by parasites or insects).

Catatonia

Catatonia is categorised into the following diagnoses:

• Catatonia associated with another mental disorder.
• Catatonia induced by substances or medications.
• Secondary catatonia syndrome.

≥3 of the following symptoms are required to diagnose catatonia, which applies to all three catatonia categories.

• Decreased Psychomotor Activity
  • Staring – Fixed gaze, decreased blinking, often with widely opened eyes.
  • Ambitendency – Appearance of being ‘motorically stuck’ in indecisive or hesitant movement.
  • Negativism – Opposing or behaving contrary to requests or instructions, which may lead to withdrawal from interaction with others (turning away) or refusal to take food or drink when offered.
  • Stupor – Immobility; no or markedly reduced psychomotor activity; minimally responsive to external stimuli.
  • Mutism – No or very little verbal response; speech may be hushed or whispered to the point of being unintelligible. (Note: do not count if speech symptoms are due to a disease of the nervous system, developmental speech or language disorder, or other disease or disorder affecting speech).
• Increased psychomotor activity
  • Extreme hyperactivity or agitation for no reason with no purposeful movements.
  • Uncontrollable, extreme emotional reactions.
  • Impulsivity (sudden engagement in inappropriate behaviour without provocation).
  • Combativeness (striking out against others, usually in an undirected manner, with or without the potential for injury).
  • Multiple manifestations of increased psychomotor activity should only be counted as one of the required three symptoms in order to meet the requirements for catatonia.
• Abnormal psychomotor activity
  • Grimacing – Odd or distorted facial expressions, often inappropriate and irrelevant to the situation.
  • Mannerisms – Odd, purposeful movements that are not appropriate to the individual’s cultural context; exaggerated caricatures of mundane movements.
  • Posturing – Spontaneous and active maintenance of a posture against gravity; sitting or standing for long periods without reacting.
  • Stereotypy – Repetitive, non-goal-directed motor activity (e.g., finger-play, repeatedly touching, patting or rubbing self); the abnormality is not inherent in the action but relates to its frequency.
  • Rigidity – Resistance by way of increased muscle tone. May range in severity from mildly increased tone to severe ‘lead pipe’ rigidity. (Requires examination.)
  • Echophenomena – Mimicking examiner’s speech (echolalia) or movements (echopraxia).
  • Verbigeration: continuous and directionless repetition of words, phrases, or sentences.
  • Waxy flexibility – Slight and even resistance to positioning by examiner. (Requires examination.)
  • Catalepsy – Passive induction of a posture (typically, examiner passively moves patient’s extremity), which remains held against gravity. (Requires examination.)

Mood disorders

Mood disorders refer to a superordinate grouping of depressive disorders and bipolar disorders. Mood disorders are defined according to particular types of mood episodes and their pattern over time. The primary types of mood episodes are:

• Depressive episode – ≥2 weeks of depressed mood or diminished interest in activities occurring most of the day, nearly every day, accompanied by other symptoms such as difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue. F>M
• Manic episode – ≥1 week, unless shortened by a treatment intervention, of euphoria, irritability, or expansiveness, and by increased activity or a subjective experience of increased energy, accompanied by other characteristic symptoms such as rapid or pressured speech, flight of ideas, increased self-esteem or grandiosity, decreased need for sleep, distractibility, impulsive or reckless behaviour, and rapid changes among different mood states (i.e., mood lability). M>F
• Mixed episode – ≥2 weeks, unless shortened by a treatment intervention, of several prominent manic and several prominent depressive symptoms consistent with those observed in manic episodes and depressive episodes, which either occur simultaneously or alternate very rapidly (from day to day or within the same day). Symptoms must include an altered mood state consistent with a manic and/or depressive episode (i.e., depressed, dysphoric, euphoric or expansive mood) and be present most of the day, nearly every day.
• Hypomanic episode – Several days of persistent elevation of mood or increased irritability as well as increased activity or a subjective experience of increased energy, accompanied by other characteristic symptoms such as increased talkativeness, rapid or racing thoughts, increased self-esteem, decreased need for sleep, distractibility, and impulsive or reckless behaviour.

Mood episodes are not diagnosable entities but are components of the following diagnoses:

Bipolar type I disorder

• Diagnosable with ≥ 1 manic or mixed episodes.
• However, the typical course of the disorder is characterised by recurrent depressive and manic/mixed episodes.
• Depressive episodes ± mixed/manic episodes arising during antidepressant treatment are grounds for a diagnosis of bipolar type I disorder if the syndrome persists after the treatment is discontinued and the full diagnostic requirements of the mood episode are met after the direct physiological effects of the treatment are likely to have receded.
• If there have been ≥ 4 mood episodes in 12 months, then rapid cycling can be assigned.

Bipolar type II disorder

• Diagnosable with ≥ 1 Hypomanic Episode and ≥ 1 depressive episode.
• Depressive episodes ± hypomanic episode arising during antidepressant treatment (e.g., medication, electroconvulsive therapy, light therapy, transcranial magnetic stimulation) is grounds for a diagnosis of bipolar type II disorder if the syndrome persists after the treatment is discontinued and the full diagnostic requirements of the mood episode are met after the direct physiological effects of the treatment are likely to have receded.
• 15% of individuals with bipolar type II disorder will subsequently develop a manic episode, resulting in a change of diagnosis to bipolar type I disorder.
• If there have been ≥ 4 mood episodes in 12 months, then rapid cycling can be assigned.

Cyclothymic Disorder

• Hypomanic and depressive symptomatology ≥ 2 years for more days than not that are never sufficiently severe or prolonged to meet the criteria for a hypomanic episode or depressive episode.

Single episode depressive disorder

• 1 depressive episode with no history of manic/mixed/hypomanic episodes.

Recurrent depressive disorder

• ≥ 2 depressive episodes separated by several months without significant mood disturbance.

Dysthymic disorder

• Depressive symptomology for ≥ 2 years for more days than not with no 2-week period where symptoms are sufficiently severe enough to meet the criteria for a depressive episode.

Mixed depressive and anxiety disorder

• Symptoms of both anxiety and depression more days than not for ≥ 2 weeks.
• Neither set of symptoms, considered separately, is sufficiently severe, numerous, or persistent to justify a diagnosis of another depressive disorder or an anxiety or fear-related disorder.

Anxiety or fear related disorders

Fear and anxiety are closely related phenomena; fear represents a reaction to a perceived imminent threat in the present, whereas anxiety is more future-oriented, referring to perceived anticipated threat. A key differentiating feature between anxiety and fear-related disorders is disorder-specific foci of apprehension, that is, the stimulus or situation that triggers the fear or anxiety. These disorders are the most prevalent disorders of childhood and adolescence.

Generalised anxiety disorder

Symptoms of anxiety that persist for ≥ several months, for more days than not, manifested by either general apprehension (i.e. ‘free-floating anxiety’) or excessive worry focused on multiple everyday events, most often concerning family, health, finances, and school or work, together with additional symptoms such as muscular tension or motor restlessness, sympathetic autonomic over-activity, subjective experience of nervousness, difficulty maintaining concentration, irritability, or sleep disturbance.

• If an individual under extremely stressful circumstances experiences impairing anxiety and worry that is appropriate to their environmental circumstances, they should not be regarded as symptomatic of GAD.

Panic disorder

Characterised by recurrent unexpected panic attacks that are not restricted to particular stimuli or situations. In addition, it is also characterised by persistent concern about the recurrence or significance of panic attacks, or behaviours intended to avoid their recurrence.

Agoraphobia

Fear or anxiety of imminent specific negative outcomes (e.g., panic attacks, symptoms of panic, incapacitation, or embarrassing physical symptoms) that are anticipated to occur in multiple situations where obtaining help or escaping might be difficult (e.g., being in crowds, being outside the home alone, or in shops). The situations are actively avoided, entered only under specific circumstances, such as in the presence of a trusted companion, or endured with intense fear or anxiety.

Specific phobia

Fear or anxiety of circumscribed situations or stimuli themselves (e.g., heights, animals, blood or injury).

Social anxiety disorder

Fear or anxiety that occurs consistently in one or more social situations such as social interactions (e.g., having a conversation), doing something while feeling observed (e.g., eating or drinking in the presence of others), or performing in front of others (e.g., giving a speech).

Separation anxiety disorder

Fear or anxiety about separation from those individuals with whom the person has a deep emotional bond. Persistent thoughts that harm or some other untoward event (e.g., being kidnapped) will lead to separation, causing ≥ several months of the following manifestations:

• Reluctance or refusal to go to school or work.
• Recurrent excessive distress (e.g., tantrums, social withdrawal) related to being separated from the attachment figure.
• Reluctance or refusal to go to sleep without being near the attachment figure.
• Recurrent nightmares about separation.
• Physical symptoms such as nausea, vomiting, stomach-ache, and headache, on occasions that involve separation from the attachment figure, such as leaving home to go to school or work.

Selective mutism

≥ 1 month of consistent selectivity in speaking, such that a child demonstrates adequate language competence in specific social situations, typically at home, but consistently fails to speak in others, typically at school.

Obsessive-compulsive or related disorders 

Obsessive-compulsive disorder

• Presence of persistent obsessions and/or compulsions.
• Obsessions are repetitive and persistent thoughts (e.g., of contamination), images (e.g., of violent scenes), or impulses/urges (e.g., to stab someone) that are experienced as intrusive and unwanted and are commonly associated with anxiety. The individual typically attempts to ignore or suppress obsessions or to neutralise them by performing compulsions.
• Compulsions are repetitive behaviours or rituals, including repetitive mental acts, that the individual feels driven to perform in response to an obsession, according to rigid rules, or to achieve a sense of ‘completeness’. Examples of overt behaviours include repetitive washing, checking, and ordering of objects. Examples of analogous mental acts include mentally repeating specific phrases in order to prevent negative outcomes, reviewing a memory to make sure that one has caused no harm, and mentally counting objects. Compulsions are either not connected in a realistic way to the feared event (e.g., arranging items symmetrically to prevent harm to a loved one) or are clearly excessive (e.g., showering daily for hours to prevent illness).
• Obsessions and compulsions impact the ability to enjoy/engage with other aspects of life.

Body dysmorphic disorder

Persistent preoccupation with defects or flaws in appearance that are either unnoticeable or only slightly noticeable to others – which derives from their concerns that an aspect of their body or appearance is perceived by others to be ugly or deformed.

• Body dysmorphic disorder is distinguished from anorexia nervosa such that preoccupations and body-image disturbance in body dysmorphic disorder are focused on features other than overall weight, shape and size (e.g., preoccupation with the nose or skin or muscle).

Olfactory reference disorder

Persistent preoccupation with the belief that one is emitting a perceived foul or offensive body odour or breath that is either unnoticeable or only slightly noticeable to others.

Hypochondriasis

Persistent preoccupation or fear about the possibility of having one or more serious, progressive or life-threatening illnesses. This is accompanied by either excessive health-related behaviours or maladaptive avoidance behaviour.

Hoarding disorder

Characterised by the accumulation of possessions that results in living spaces becoming cluttered to the point that their use or safety is compromised. Accumulation occurs due to both repetitive urges or behaviours related to amassing items, which may be passive (e.g., accumulation of incoming flyers or mail) or active (e.g., excessive acquisition of free, purchased, or stolen items), and difficulty discarding possessions due to a perceived need to save items and distress associated with discarding them.

Body-focused repetitive behaviour disorder

Recurrent and habitual actions directed at the outermost layer of the body (e.g. hair-pulling, skin-picking, lip-biting), typically accompanied by unsuccessful attempts to decrease or stop the behaviour involved, which lead to dermatological sequelae.

• Subcategorised into – Trichotillomania (hair-pulling) and excoriation disorder (skin-picking).

Disorders specifically associated with stress

Post-traumatic stress disorder

Exposure to an event or situation (either short- or long-lasting) of an extremely threatening or horrific nature leading to the development of a characteristic syndrome lasting at least several weeks of:

• Re-experiencing the traumatic event in the present.
• Deliberate avoidance of reminders likely to produce re-experiencing.
• Persistent perceptions of heightened current threat.

Complex post-traumatic stress disorder

All diagnostic requirements for PTSD are met. In addition, complex PTSD is characterised by severe and persistent:

• Problems in affect regulation.
• Beliefs about oneself as diminished, defeated or worthless, accompanied by feelings of shame, guilt or failure related to the traumatic event.
• Difficulties in sustaining relationships and in feeling close to others.

Prolonged grief disorder

Following the death of a partner, parent, child, or other person close to the bereaved, there is persistent and pervasive (≥ 6 months) grief response characterised by longing for the deceased or persistent preoccupation with the deceased accompanied by intense emotional pain (e.g. sadness, guilt, anger, denial, blame, difficulty accepting the death, feeling one has lost a part of one’s self, an inability to experience positive mood, emotional numbness, difficulty in engaging with social or other activities).

Adjustment disorder

Preoccupation with the stressor or its consequences, including excessive worry, recurrent and distressing thoughts about the stressor, or constant rumination about its implications, as well as failure to adapt to the stressor. (The stressor can be of any severity or any type and is not necessarily of an extremely threatening or horrific nature).

• Once the stressor and its consequences have ended, the symptoms resolve within 6 months.

Reactive attachment disorder

Characterised by grossly abnormal attachment behaviours in early childhood, occurring in the context of a history of grossly inadequate child care (e.g., severe neglect, maltreatment, institutional deprivation). Even when an adequate primary caregiver is newly available, the child does not turn to the primary caregiver for comfort, support and nurture, rarely displays security-seeking behaviours towards any adult, and does not respond when comfort is offered. Reactive attachment disorder can only be diagnosed in children, and features of the disorder develop within the first 5 years of life. However, the disorder cannot be diagnosed before the age of 1 year (or a developmental age of less than 9 months).

• Caregiver neglect during the first 9 months of life is often an associated precursor to the onset of the disorder.
• With the provision of adequate care, children with reactive attachment disorder often experience a near or complete remission of symptoms. If appropriate caregiving is not provided, the disorder can persist for several years.

Disinhibited social engagement disorder

Characterised by grossly abnormal social behaviour occurring in the context of a history of grossly inadequate child care (e.g., severe neglect, maltreatment, institutional deprivation). The child approaches adults indiscriminately, lacks reticence to approach, will go away with unfamiliar adults, and exhibits overly familiar behaviour towards strangers. Disinhibited social engagement disorder can only be diagnosed in children, and features of the disorder develop within the first 5 years of life. However, the disorder cannot be diagnosed before the age of 1 year (or a developmental age of less than 9 months).

Dissociative disorders

Dissociative neurological symptom disorder

Involuntary disruption or discontinuity in the normal integration of motor, sensory, or cognitive functions, lasting at least several hours (includes the concept previously known as conversion disorder).

• Clinical findings are inconsistent with a recognised nervous system disease (e.g., a stroke) or another medical condition (e.g., a head injury).
• Gait disturbances and non-epileptic seizures are the most prominent and the most frequent symptoms of dissociative neurological symptom disorder in children and adolescents.

Dissociative amnesia ± fugue

Characterised by an inability to recall important autobiographical memories, typically of recent traumatic or stressful events, that is inconsistent with ordinary forgetting.

• Dissociative fugue is a loss of a sense of personal identity and sudden travel away from home, work, or significant others for an extended period of time (days or weeks). A new identity may be assumed.

Trance disorder

Characterised by trance states in which there is a marked alteration in the individual’s state of consciousness or a loss of the individual’s customary sense of personal identity in which the individual experiences a narrowing of awareness of immediate surroundings or unusually narrow and selective focus on environmental stimuli and restriction of movements, postures, and speech to repetition of a small repertoire that is experienced as being outside of one’s control. The trance state is not characterised by the experience of being replaced by an alternate identity.

Possession trance disorder

Occurrence of a trance state in which there is a marked alteration in the individual’s state of consciousness, and the individual’s normal sense of personal identity is replaced by an external ‘possessing’ identity. The trance state is characterised by behaviours or movements that are experienced as being controlled by the possessing agent. Trance episodes are attributed to the influence of an external ‘possessing’ spirit, power, deity or other spiritual entity.

Dissociative identity disorder & partial dissociative identity disorder

Dissociative identity disorder	Partial dissociative identity disorder
Discontinuities in agency and sense of self are marked (manifested in episodes of executive control, often including amnesia and greater elaboration of the personality states).	Discontinues are less pronounced.
≥2 distinct personality states recurrently take executive control of the individual’s consciousness and functioning to the extent that they function in daily life or engage in relatively elaborate patterns of behaviour in specific situations.	The non-dominant, alternate personality states do not recurrently take executive control of the individual’s consciousness and functioning to the extent that they perform in specific aspects of daily life, although there may be occasional, limited and transient episodes in which a distinct personality state assumes executive control to engage in circumscribed behaviours (e.g., in response to extreme emotional states, episodes of self-harm, or the re-enactment of traumatic memories).
Personality states are elaborate – not just exclusively involved in re-enacting traumatic memories.	The non-dominant alternate personality states are not elaborated to the extent observed in dissociative identity disorder.
There are typically (although not always) significant episodes of amnesia, which may be severe.	Amnesia, if present, is usually brief and restricted to extreme emotional states or episodes of self-harm.

Depersonalisation-derealisation disorder

Characterised by persistent or recurrent experiences of depersonalisation, derealisation, or both.

• Depersonalization is characterised by experiencing the self as strange or unreal or feeling detached from, or as though one were an outside observer of, one’s thoughts, feelings, sensations, body, or actions.
• Derealization is characterised by experiencing other persons, objects, or the world as strange or unreal (e.g., dreamlike, distant, foggy, lifeless, colourless, or visually distorted) or feeling detached from one’s surroundings.
• During experiences of depersonalisation or derealisation, reality testing remains intact.

Feeding or eating disorders

Anorexia nervosa

Significantly low body weight for the individual’s height, age, developmental stage, or weight history. A commonly used threshold is:

	Adults	Children and adolescents
Significantly low body weight	BMI 14.0-18.5 kg/m²	BMI-for-age 0.3-5ᵗʰ percentile
Dangerously low body weight	BMI < 14.0 kg/m²	BMI-for-age <0.3 percentile

• They are further subcategorised into:
  • Restricting pattern (induce weight loss by restricting food intake or fasting alone ±increased energy expenditure but no binge eating or purging behaviours).
  • Binge-purge pattern (induce weight loss by restricted food intake + significant purging behaviours aimed at getting rid of ingested food).
• Associated with:
  • Persistent pattern of restrictive eating.
  • Behaviours aimed at establishing and maintaining abnormally low body weight.
  • Fear of weight gain.
  • Increasing energy expenditure.
  • Excessive preoccupation with overall body weight, shape or size.
• Rapid weight loss (>20% of total body weight within 6 months) may also replace significantly low body weight as a diagnostic criterion if the associations above are also present.
• F>M 4:1 with prevalence of 0.4%.

Bulimia nervosa

Frequent, recurrent episodes of binge eating (e.g., once a week or more over a period of ≥1 month). Binge eating is defined as a discrete period of time (e.g., 2 hours) during which the individual experiences a loss of control over their eating behaviour and eats notably more or differently than usual.

• In binge eating, the amount may be ‘objectively’ big by objective standards or ‘subjectively’ large as subjectively experienced by the individual. In either case, the core feature of a binge eating episode is the loss of control.
• Repeated inappropriate compensatory behaviours to prevent weight gain (e.g., once a week or more over a period of ≥ 1 month).

Binge eating disorder

Characterised by frequent, recurrent episodes of binge eating (e.g. once a week or more over a period of 3 months). Binge eating is experienced as very distressing and is often accompanied by negative emotions such as guilt or disgust. However, unlike in Bulimia Nervosa, binge eating episodes are not regularly followed by inappropriate compensatory behaviours aimed at preventing weight gain.

Avoidant-restrictive food intake disorder

Characterised by avoidance or restriction of food intake that results in:

• The intake of an insufficient quantity or variety of food to meet adequate energy or nutritional requirements that have resulted in significant weight loss, clinically significant nutritional deficiencies, dependence on oral nutritional supplements or tube feeding, or has otherwise negatively affected the physical health of the individual; or significant impairment in personal, family, social, educational, occupational or other important areas of functioning.
• Not motivated by a preoccupation with body weight or shape.

Pica

Characterised by the regular consumption of non-nutritive substances, such as non-food objects and materials (e.g., clay, soil, chalk, plaster, plastic, metal and paper) or raw food ingredients (e.g., large quantities of salt or corn flour) that is persistent or severe enough to require clinical attention in an individual who has reached a developmental age at which they would be expected to distinguish between edible and non-edible substances (approximately 2 years).

Rumination-regurgitation disorder

Characterised by the intentional and repeated bringing up of previously swallowed food back to the mouth (i.e., regurgitation), which may be re-chewed and re-swallowed (i.e. rumination) or maybe deliberately spat out (but not as in vomiting). The regurgitation behaviour is frequent (at least several times per week) and sustained over a period of at least several weeks.

• Only diagnosed in individuals who have reached a developmental age of at least 2 years.

Elimination disorders

Enuresis

Enuresis is the repeated voiding of urine into clothes or beds, which may occur during the day or at night in an individual who has reached a developmental age when urinary continence is ordinarily expected (5 years).

Encopresis

Repeated passage of faeces in inappropriate places. Encopresis should be diagnosed if inappropriate passage of faeces occurs repeatedly (e.g., at least once per month over a period of several months) in an individual who has reached the developmental age when faecal continence is ordinarily expected (4 years).

Disorders of bodily distress or bodily experience

Bodily distress disorder

Involves bodily symptoms that the individual finds distressing and to which excessive attention is directed.

• Typically, this involves multiple bodily symptoms that may vary over time. Occasionally, the focus is limited to a single symptom, usually pain or fatigue.
• Repeated contacts with health care providers related to the bodily symptoms that are substantially in excess.
• Unlike individuals with hypochondriasis who are preoccupied with the possibility of having one or more serious, progressive, or life-threatening illnesses, individuals with bodily distress disorder are typically preoccupied with the symptoms themselves and the impact of the symptoms on their lives. Individuals with hypochondriasis may also seek medical attention, but their primary purpose is to obtain reassurance that they do not have the feared serious medical condition. Individuals with bodily distress disorder typically seek medical attention in order to get relief from their symptoms, not to disconfirm the belief that they have a serious medical illness.

Body integrity dysphoria

Involves a disturbance in the person’s experience of the body manifested by the persistent desire to have a specific physical disability accompanied by persistent discomfort or intense feelings of inappropriateness concerning current non-disabled body configuration.

Disorders due to substance use or addictive behaviours

Disorders due to substance use

Disorders related to 14 classes or groups of psychoactive substances are included. Typically, initial use of these substances produces pleasant or appealing psychoactive effects that are rewarding and reinforcing with repeated use. With continued use, many of the included substances have the capacity to produce dependence. They also have the potential to cause numerous forms of harm, both to mental and physical health.

• Each substance class or group is classified into some of these diagnostic subcategories, defined as:
  • Harmful pattern of use of [substance X] – Evident over a period of ≥12 months if substance use is episodic or at least one month if use is continuous.
  • [Substance X] dependence – The characteristic feature is a strong internal drive to use [Substance X], which is manifested by impaired ability to control use, increasing priority given to use over other activities and persistence of use despite harm or negative consequences.
  • [Substance X] intoxication – Transient condition that develops during or shortly after the consumption of opioids that is characterised by disturbances in consciousness, cognition, perception, affect, behaviour, or coordination. The features of dependence are usually evident over a period of ≥12 months, but the diagnosis may be made if use is continuous (daily or almost daily) for ≥3 months.
  • [Substance X] withdrawal – A clinically significant cluster of symptoms, behaviours and/or physiological features, varying in degree of severity and duration, that occurs upon cessation or reduction of use of [substance X] in individuals who have developed dependence or have used [substance X] for a prolonged period or in large amounts.
  • [Substance X] induced delirium or psychotic disorder.

Disorders due to addictive behaviours

Mainly subcategorised into:

• Gambling disorder – Impaired control over gambling, increasing priority given to gambling over other interests and daily activities, and continuation of gambling despite negative consequences.
• Gaming disorder – Impaired control over gaming, increasing priority given to gaming over other interests and daily activities, continuation of gaming despite negative consequences.
• The pattern of repetitive behaviour may be continuous or episodic and recurrent but is manifested over an extended period of time, e.g. ≥ 12 months.
• Each is further subcategorised into ‘Predominantly offline’ or ‘Predominantly online’.
• If gaming behaviour is focused on wagers (e.g. internet poker), gambling disorder may be a more appropriate diagnosis.

Impulse control disorders

Pyromania

Characterised by a recurrent failure to control strong impulses to set fires, resulting in multiple acts of, or attempts at, setting fire to property or other objects in the absence of an apparent motive.

Kleptomania

Characterised by a recurrent failure to control strong impulses to steal objects in the absence of an apparent motive.

Compulsive sexual behaviour disorder

Characterised by a persistent pattern (e.g., 6 months or more) of failure to control intense, repetitive sexual impulses or urges resulting in repetitive sexual behaviour.

Intermittent explosive disorder

Characterised by repeated brief episodes of verbal or physical aggression or destruction of property that represent a failure to control aggressive impulses in an individual who is at least 6 years of age, with the intensity of the outburst or degree of aggressiveness being grossly out of proportion to the provocation or precipitating psychosocial stressors.

Disruptive behaviour or dissocial disorders 

Oppositional defiant disorder

Persistent pattern (e.g., 6 months or more) of markedly defiant, disobedient, provocative or spiteful behaviour that occurs more frequently than is typically observed in individuals of comparable age and developmental level and that is not restricted to interaction with siblings.

Subcategorised into ± chronic irritability-anger, defined as often feeling angry or resentful, showing bitterness toward others, or feeling as if things are unfair; often being touchy or easily annoyed; exhibiting oversensitivity or irritation to minimal or perceived provocations; often losing temper, exhibiting angry verbal or behavioural outbursts.

Conduct-dissocial disorder

Persistent pattern of behaviour (>1 year) in which the basic rights of others or major age-appropriate social or cultural norms, rules, or laws are violated. Typically, there are multiple behaviours involved, including one or more of the following:

• Aggression towards people or animals.
• Destruction of property, such as deliberate fire setting with the intention of causing serious damage.
• Deceitfulness or theft.
• Serious violations of rules.

Subcategorised as childhood-onset (<10 years of age) or adolescent onset (≥10 years of age).

Personality disorders and related traits

Personality disorder

Characterised by problems in the functioning of aspects of the self (e.g., identity, self-worth, accuracy of self-view, self-direction) and/or interpersonal dysfunction (e.g., ability to develop and maintain close and mutually satisfying relationships, ability to understand others’ perspectives and to manage conflict in relationships) that have persisted over an extended period of time (e.g., 2 years or more).

• Subcategorised into mild, moderate, severe.

Prominent personality traits or patterns

Trait domain qualifiers may be applied to personality disorders or personality difficulty to describe the characteristics of the individual’s personality that are most prominent and that contribute to personality disturbance.

• Negative affectivity (broad range of disproportional negative emotions, emotional lability, negativistic attitudes, low self-esteem and self-confidence, mistrustfulness).
• Detachment (social and emotional detachment).
• Dissociality (self-centredness and lack of empathy).
• Disinhibition (impulsivity, distractibility, irresponsibility, recklessness, lack of planning).
• Anankastia (perfectionism, emotional and behavioural constraint).
• Borderline pattern (pervasive pattern of instability of interpersonal relationships, self-image, and affects, and marked impulsivity, indicated by ≥5 of the following:
  • Frantic efforts to avoid real or imagined abandonment.
  • A pattern of unstable and intense interpersonal relationships, which may be characterised by vacillations between idealisation and devaluation, typically associated with both a strong desire for and fear of closeness and intimacy.
  • Identity disturbance, manifested in markedly and persistently unstable self-image or sense of self.
  • A tendency to act rashly in states of high negative affect, leading to potentially self-damaging behaviours (e.g., risky sexual behaviour, reckless driving, excessive alcohol or substance use, binge eating).
  • Recurrent episodes of self-harm (e.g., suicide attempts or gestures, self-mutilation).
  • Emotional instability due to marked reactivity of mood. Fluctuations of mood may be triggered either internally (e.g., by one’s own thoughts) or by external events. As a consequence, the individual experiences intense dysphoric mood states, which typically last for a few hours but may last for up to several days.
  • Chronic feelings of emptiness.
  • Inappropriate, intense anger or difficulty controlling anger manifested in frequent displays of temper (e.g., yelling or screaming, throwing or breaking things, getting into physical fights).
  • Transient dissociative symptoms or psychotic-like features (e.g., brief hallucinations, paranoia) in situations of high affective arousal.

Paraphilic disorders

Exhibitionistic disorder

Involves exposing one’s genitals to an unsuspecting individual in public places, usually without inviting or intending closer contact.

Voyeuristic disorder

Involves observing an unsuspecting individual who is naked, in the process of disrobing, or engaging in sexual activity.

Paedophilic disorder

Involves pre-pubertal children.

Coercive sexual sadism disorder

Involves the infliction of physical or psychological suffering on a non-consenting person.

Frotteuristic Disorder

Involves touching or rubbing against a non-consenting person in crowded public places.

Other paraphilic disorders involving non-consenting individuals 

Involves others who are unwilling or unable to consent, but that is not specifically described in any of the other named paraphilic disorders categories (e.g., arousal patterns involving corpses or animals).

Paraphilic disorders involving solitary behaviour or consenting individuals

Involves consenting adults or solitary behaviours. One of the following two elements must be present: 1) The person is markedly distressed by the nature of the arousal pattern, and the distress is not simply a consequence of rejection or feared rejection of the arousal pattern by others; or 2) The nature of the paraphilic behaviour involves significant risk of injury or death either to the individual or to the partner (e.g., asphyxiaphilia).

Factitious disorders

Factitious disorder imposed on self

Characterised by feigning, falsifying, or inducing medical, psychological, or behavioural signs and symptoms or injury associated with identified deception.

Factitious disorder imposed on another

Characterised by feigning, falsifying, or inducing medical, psychological, or behavioural signs and symptoms or injury in another person, most commonly a child dependent, associated with identified deception.
Individuals with bodily distress disorder or hypochondriasis may exaggerate their symptoms at times to ensure that their care is prioritised or taken seriously as a part of excessive attention and treatment seeking related to somatic symptoms. There is no evidence that the person is feigning, falsifying, or intentionally inducing or aggravating the symptoms.

In malingering, primary external incentives are considered to be motivating the behaviour. The most common external motives for malingering include evading criminal prosecution, obtaining psychoactive medications (e.g., opioids), avoiding military conscription or dangerous military duty, and attempting to obtain sickness or disability benefits or improvements in living conditions such as housing. Malingering is not considered a mental disorder.

Neurocognitive disorders

Delirium

Characterised by a disturbance of attention, orientation, and awareness that develops within a short period of time, typically presenting as significant confusion or global neurocognitive impairment, with transient symptoms that may fluctuate depending on the underlying causal condition or aetiology.

Mild neurocognitive disorder

Characterised by mild impairment in one or more cognitive domains relative to that expected given the individual’s age and general premorbid level of cognitive functioning, which represents a decline from the individual’s previous level of functioning.

Amnestic disorder

Characterised by prominent memory impairment relative to expectations for age and general premorbid level of cognitive functioning, which represents a decline from the individual’s previous level of functioning in the absence of other significant cognitive impairment.

Dementia

Covered more extensively in other chapters but classified within the ICD-11 as follows:

• Due to Alzheimer’s disease.
• Due to cerebrovascular disease.
• Due to Lewy body disease.
• Frontotemporal dementia.
• Due to psychoactive substances, including medications:
  • Due to alcohol.
  • Due to sedatives, hypnotics, anxiolytics.
  • Due to volatile inhalants.
• Due to diseases classified elsewhere:
  • Due to Parkinson’s disease.
  • Due to Huntington’s disease.
  • Due to exposure to heavy metals/toxins.
  • Due to HIV.
  • Due to multiple sclerosis.
  • Due to prion disease.
  • Due to normal pressure hydrocephalus.
  • Due to injury to the head.
  • Due to pellagra.
  • Due to Down syndrome.
• Behavioural or psychological disturbances in dementia
  • Psychotic symptoms.
  • Mood symptoms.
  • Anxiety symptoms.
  • Apathy.
  • Agitation or aggression.
  • Disinhibition.
  • Wandering.

DSM-V

The DSM, on the other hand, is produced by the American Psychiatric Association (APA) and is widely used in the US and other countries. It provides a diagnostic framework for mental disorders and is currently in its fifth edition (DSM-5), published in 2013. One of the key changes from the DSM IV to V was the reorganisation of its multiaxial system.

The new multiaxial system now includes only three axes – psychiatric disorder, psychosocial and environmental factors associated with them, and the severity of the associated disability. In effect, this means personality disorders are treated with the same importance as other psychiatric disorders. This has moved DSM’s multiaxial system closer to ICD’s multiaxial system.

The challenges of classifying mental illness

Despite the widespread use of the ICD in the UK, the classification of mental health conditions is not without controversy, and they are not always beneficial to patients either.

Pros Provides a common language for mental health professionals and researchers to communicate about mental health conditions. This helps to facilitate international collaboration and the sharing of knowledge and best practices. Widely used and recognised by national health systems and insurance providers, making it an important tool for ensuring access to mental health care and support. Allows for a common understanding of the various mental health conditions that exist, which can help in the development of effective treatment plans. For example, having a standardised classification system means that a patient in one part of the world can receive a diagnosis that is recognised and treated similarly in another part of the world. Assists in the allocation of resources, such as funding for research and treatment, as well as the development of public policy. Depending on the individual’s preferences and attitudes, the classification of mental illness can reduce the stigma associated with mental health conditions. By having a standardised system, mental health conditions can be framed as ‘real’, biologically based illnesses rather than being seen as a personal weakness or moral failing. This can help reduce the shame and isolation that individuals with mental health conditions often experience.

Cons The classifications of mental illness are often based on subjective criteria, such as reported symptoms and behaviours, rather than objective, biologically based markers. This can make it difficult to diagnose conditions accurately and consistently across individuals and populations. Diagnoses are also not homogenous: two patients with the same diagnosis may present with totally different symptoms. Diagnoses are not clear-cut. There are overlapping symptoms between different mental disorders, and a patient may present with symptoms that don’t fit neatly into a single diagnostic category. Diagnoses are not explanatory but merely descriptive. It cannot make claims around causality the same way that the diagnosis ‘breast cancer’ can allude to her abnormal histology that explains her symptoms Some diagnoses may be overemphasised or underdiagnosed based on the biases and prejudices of healthcare providers and society as a whole. Mental health concepts and diagnoses are shaped by the prevailing attitudes, beliefs, and values of a particular time and place. There can be significant variation in the prevalence and diagnosis of certain conditions between different countries and cultures, leading to questions about the universality of the diagnostic criteria and the cultural specificity of the disorders. The ICD can be complex and difficult for non-specialists to understand, requiring specialised training and knowledge to use it effectively. Depending on the individual’s preferences and attitudes, diagnoses associated with the ICD may contribute to even more stigma and discrimination against individuals with mental health conditions.

Despite these criticisms, the ICD-11 is still widely used and recognised as a valuable tool for understanding and classifying mental health conditions in clinical settings today. However, it is important to recognise the limitations and potential biases of any diagnostic system and to use it in a thoughtful and nuanced manner.

References

• Foucault, M. (2003). Madness and civilisation. Routledge.
• Patrick, C. J., & Hajcak, G. (2016). RDoC: Translating promise into progress. Psychophysiology, 53(3), 415-424.
• Keyes, C. L. (2002). The mental health continuum: From languishing to flourishing in life. Journal of health and social behaviour, 207-222.