7th November 2023

Specific Delusions

Delusion of love

It is also known as erotomania or de Clérambault’s syndrome. The patient comes to believe that a specific other person is in love or infatuated with them, although this is, in fact, not the case. The other person may have not even had any previous contact with them. The disorder is more common in women. The other person is more commonly a male of high social status or already in a relationship.

Delusion of love is associated with personality disorders and other delusional disorders such as schizophrenia.

If severe enough, it can be associated with problematic behaviours such as sending letters/emails or other forms of communication, stalking and unwanted physical contact.

Delusion of unfaithfulness

Also known as Othello syndrome. Jealousy is a common emotion that everyone has experienced, but this diagnosis is made when there is a delusional and irrational component to the person’s jealousy.

It has mixed aetiology, often appearing in both functional and organic disorders. In fact, it has been demonstrated that at least 30% of cases have neurological underpinnings, frequent alcohol dependency and dementia (Cipriani et al., 2012).

Pre-morbidly, the person is typically described as being suspicious, sensitive and mildly jealous.

The presenting person may misinterpret the ordinary actions of their partner as being indicative of their unfaithfulness. For example, if the partner buys new underwear, the person may become convinced that the reason behind this is to show off to the partner’s new spouse.

The disorder may result in problematic behaviours, such as a reprisal attack against the partner, which may occur with little predictability.

Delusion of ill health

The patient is convinced that they are not physically well. This is most associated with depressive disorder but is also seen in schizophrenia. It often takes a significant length of time to respond to treatment. Pre-morbidly, the patient frequently exhibits some health anxieties, which are magnified along the course of their depressive/schizophrenic illness.

The individual’s delusion may even extend to their family, such that a person may become convinced that their parent or child is dying, and so murder them with the thought that they are helping to end their suffering.

These delusions can result in hypochondriasis, the belief that one is unwell with a specific medical condition.

They may also result in a sense of incurable insanity, in which the person believes their mental illness is resistant to any form of treatment and refuses to accept any form of help from their psychiatric team, resulting in problems with engagement and treatment compliance problems.

Delusions of guilt

This is observed in depression. The intensity of the delusion and magnitude of the guilt is proportional to the severity of the depression.

In mild depression, a patient may feel guilty about a specific past event in their life and say something like: ‘Not being present enough in my daughter’s upbringing made her fail that exam.’

In moderate depression, the consequence of their guilt about something specific may be extended. For example: ‘Not being present enough in my daughter’s upbringing ruined her whole life.’

In severe depression, the delusions of guilt may even absorb a grandiose flavour, with such content as: ‘I’m the most wicked person in the world.’ They often lead to suicide (Higgins, 1990).

Delusional misidentification

Delusional misidentification includes both Capgras’ syndrome, Frégoli’s syndrome and the Syndrome of subjective doubles.

Capgras’ syndrome refers to the condition whereby someone believes with delusional intensity that another person, usually someone closely related to them, has been replaced by an exact double.

Frégoli’s syndrome denotes a person believing that someone unfamiliar to them is actually familiar, even though there bears no physical resemblance.

Syndrome of subjective doubles is the belief that doubles of the person exist, although, in fact, these other people have no relation to him.

Syndromes of delusional misidentification occur in a variety of both functional and organic conditions. Functional conditions include both schizophrenia and bipolar affective disorder. Organic include dementia, acquired brain injury, epilepsy, and stroke (Edelstyn et al., 1999). In cases of organic aetiology, the right frontal and temporal regions have been found to be pathological, which are areas associated with facial recognition.

Religious delusions

Often, the setting for these delusions is a person with some religious background. The religious beliefs become delusional when they become amplified beyond what is reasonable in the context of that religion. For example, a person who believes that members of her church have become possessed by Satan. This is clearly not a view that would be held by the majority of that congregation.

Nihilistic delusions

The patient will deny they exist, that they have a body and may even deny that others exist or the world around them exists. It most commonly occurs in severe depression but is also seen in schizophrenia and delirium.

An example of a nihilistic delusion is Cotard’s syndrome, in which the person believes they are dead or does not exist. Nihilistic delusions are the opposite of grandiose delusions, and feelings of guilt and hypochondriasis are prominent.

Delusions of infestation

The patient believes that they are infested with insects or small organisms. Also known as Ekbom’s syndrome. They may experience this as a tactile hallucination or a delusion. The syndrome has different aetiologies, including depressive psychosis, paranoid schizophrenia, delirium tremens, cocaine addiction, stroke and dementia.

Pseudocyesis

A delusion whereby a woman believes that she is pregnant, although she is not. However, there can be clinical symptoms and signs that convince the person that they are, including menstrual disturbance, nausea, breast changes and abdominal distension.

Grandiose delusion

Grandiose delusions are delusional beliefs that one is special in some way, either in the form of identity or ability. For example, a grandiose delusion of identity could be the belief that one is Superman, the Prime Minister, or even God. Beliefs that one is rich can result in excessive spending, and therefore, protecting the patient’s finances is important, even if it means preventing them from having access to their bank account or spending means whilst they are unwell.

Grandiose delusions of ability could include the belief that one is a talented singer, a brilliant inventor, or that one can fly. As a result of delusions such as the latter, mania results in a significant risk profile and harm to self or even death can result from recklessness and feelings of invincibility.

Grandiose delusions are associated with manic presentations, for example, in bipolar affective disorder or schizoaffective disorder. These delusions may develop in response to auditory hallucinations, for example, a voice telling the person that they are a talented musician. This is a good example of how some auditory hallucinations can be non-distressing, occasionally resulting in patients avoiding treatment.

Persecutory (paranoid) delusion

This is a delusional belief that one is being harmed in some way. It is most associated with paranoid schizophrenia. However, this can also be present in depression with psychosis, whereby the patient may feel he is so evil that he deserves to be spied on. Examples include the belief that one is being poisoned, their mobile or computer is being hacked, they are being monitored by another person or external organisation, or they are being tortured.

Often, in psychiatry, we see paranoid and persecutory being used interchangeably to describe delusions of this nature. However, strictly speaking, the correct meaning of the word ‘paranoid’ is ‘delusional’, and therefore, it is correct to use the term ‘persecutory’. Paranoid simply refers to the person believing that the delusion is referring to themselves. It is not, therefore, the same as persecutory.

Hypochondriacal delusion

A hypochondriacal delusion is a delusional belief that one is suffering from a specific medical condition.

The patient will classically approach their medical practitioner requesting to be investigated for a specific condition, although no organic pathology will be identified. The patient refuses to accept the advice and evidence put forward to them by the medical practitioner and so will return requesting further investigations or will seek another practitioner’s advice, convinced that something must be wrong.

Referential delusion

A referential delusion, or idea of reference, is the false belief by the patient that everything occurring around them is related. This can manifest by the patient thinking that a news anchor on the TV is talking directly to them, or that a singer on the radio, or a journalist in a newspaper are doing the same thing, to name a few examples.

Folie à deux

This can be translated from the French as ‘madness by two’.

This fascinating syndrome occurs when a delusion is transmitted from a psychotic person to another person. The other person is most commonly a partner, family relative, or close friend.

Treatment involves treating the person who transmitted the psychosis and separating them from the other person. These two actions indirectly result in the treatment of the other person.

References

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