29th January 2024

Diagnosis

Schizophrenia should be suspected in any individual presenting with symptoms suggestive of psychosis and disorganised behaviour with significant deterioration in their social functioning. There are two diagnostic manuals that can aid in the diagnostic process: DSM-V and WHO ICD10. DSM-V is a classification manual used in the United States, whereas WHO ICD10 is used in the UK. For practical reasons, we will be discussing ICD10 diagnostic criteria.

Diagnostic criteria 

ICD10 outlines that at least one of the symptoms or syndromes listed under (1), or at least two of the symptoms and signs under (2) should be present most of the time during an episode, for 1 month (or at least some of the time most of the days). These symptoms MUST be in the absence of substance misuse or an organic cause (e.g. brain tumour, temporal lobe epilepsy) or significant mood disorder. Once a diagnosis of schizophrenia has been established, it can be further sub-classified based on prominent symptomatology.

Source: Adapted from: World Health Organisation. ICD-10 classification of mental and behavioural disorders: Diagnostic criteria for research [internet]. World Health Organisation; 1993 [cited 2022 July 14]. Available from: https://apps.who.int/iris/bitstream/handle/10665/37108/9241544554.pdf 

Paranoid Schizophrenia:

This is the commonest type of Schizophrenia worldwide. To make the diagnosis, there must be a strong persecutory and paranoid nature to the delusions or hallucinations, often both. Disturbances in speech, affect, or catatonia may be present; however, they are characteristically not prominent. The most common paranoid delusions present are delusions of persecution or grandeur. Common examples of paranoid hallucinations include threatening and commanding auditory hallucinations. Paranoid schizophrenia is episodic with partial or complete remission of symptoms. In chronic cases, the symptoms may persist for several years without ever gaining insight. In such cases,  it can be difficult for the patient to adhere to a treatment plan. It may be appropriate to consult appropriate legal frameworks that will allow the covert administering of medication in the patient’s best interests.

Hebephrenic/disorganised Schizophrenia

This form of schizophrenia, also known as ‘disorganised schizophrenia,’ describes a presentation in which affective changes and disorganised behaviour and speech are prominent. Observing these individuals will identify extreme activity that is purposeless and non-constructive. Characteristically, their thought patterns and speech are obviously disorganised and incoherent. They may be seen laughing or smiling inappropriately, demonstrating an incongruent effect characteristic of this subtype. Hebephrenic schizophrenia usually develops between the ages of 15-25 and can only be diagnosed if the onset is within this age range. They carry a poorer prognosis compared to other forms of schizophrenia due to the rapid development of negative symptoms. Hallucinations and delusions may be present but are not normally prominent. A period of observation over 2-3 months is essential in making the diagnosis.

Catatonic schizophrenia 

This form of schizophrenia is now relatively uncommon in Western countries. Classically, patients demonstrate a marked change in motor function. This can include: stupor (marked reduction in reactivity to environment, spontaneous movements and activity), mutism, rigidity (stiff, immobile posture that cannot be moved by someone else), waxy flexibility (maintenance of limbs and body in a position created by someone else), command automation (immediately following the commands of someone else) and perseveration (repetition of a response, gesture, or phrase). Although the term catatonic reflects the hypoactive behaviours characteristic of this subtype, individuals can show periodic hyperactive behaviour, often alternating between the two. In patients with catatonic schizophrenia, it is especially important to monitor their physical health as they can become malnourished due to prolonged catatonic states.

Undifferentiated schizophrenia 

The category is reserved for patients that meet the diagnostic criteria for schizophrenia and either fail to meet the specific criteria for one specific subtype, or they have multiple symptoms qualifying for more than one subtype.

Residual schizophrenia 

This diagnosis applies to individuals who have had at least one clear-cut episode of active schizophrenia and continue to present with symptoms to a much lesser extent. Often, the positive symptoms, such as delusions and hallucinations, are markedly reduced, whereas negative symptoms, such as blunted affect, poverty of speech and psychomotor retardation continue to persist.

Simple schizophrenia 

This is a fairly uncommon disorder with an insidious onset. The individual demonstrates a progressive development of negative symptoms by becoming more blunted in affect, loss of drive and interest, paucity of speech and passivity, which leads to a marked decline in social, occupational, or educational performance. It is important to note that these individuals will not have experienced any psychotic symptoms such as delusions or hallucinations and do not meet the criteria for any of the other schizophrenia subtypes.

Post schizophrenic depression 

In this subcategory, the individual meets the diagnostic criteria for schizophrenia and has had an acute episode within the last 12 months. Some of the symptoms are still present (most often the negative symptoms), as they begin to experience low mood symptoms that are more prominent than the schizophrenic symptoms. The low mood symptoms must be present for a minimum of two weeks. If the individual no longer has any schizophrenic symptoms, then the diagnosis is now depression, whereas if the schizophrenic symptoms are still present and more prominent than the low mood symptoms, then the diagnosis of the schizophrenic subtype should persist.