21 - 6A24 Delusional disorder

6A24 Delusional disorder

185 Schizophrenia and other primary psychotic disorders Delusional disorder Essential (required) features • The presence of a delusion or set of related delusions, typically persisting for at least 3 months and often much longer, in the absence of a depressive, manic or mixed episode is required for diagnosis. • The delusions are variable in content across individuals, while showing remarkable stability within individuals, although they may evolve over time. Common forms of delusions include persecutory, somatic (e.g. a belief that organs are rotting or malfunctioning despite normal medical examination), grandiose (e.g. a belief that one has discovered an elixir that gives eternal life), jealous (e.g. the unjustified belief that one’s spouse is unfaithful) and erotomanic (i.e. the belief that another person, usually a famous or high-status stranger, is in love with the person experiencing the delusion). • Absence of clear and persistent hallucinations; severely disorganized thinking (formal thought disorder); experiences of influence, passivity or control; or negative symptoms characteristic of schizophrenia is evident. 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). • Apart from the actions and attitudes directly related to the delusional system, affect, speech and behaviour are typically unaffected. • The symptoms are not a manifestation of another medical condition (e.g. a brain tumour), are not due to the effects of a substance or medication on the central nervous system (e.g. corticosteroids) – including withdrawal effects (e.g. from alcohol) – and are not better accounted for by another mental disorder (e.g. another primary psychotic disorder, a mood disorder, an obsessive-compulsive or related disorder, an eating disorder). Course specifiers for delusional disorder The following specifiers should be applied to identify whether the individual currently meets the diagnostic requirements of delusional disorder or is in partial or full remission. Delusional disorder, currently symptomatic • All diagnostic requirements for delusional disorder in terms of symptoms and duration are currently met, or have been met within the past month. 6A24 6A24.0 Schizophrenia and other primary psychotic disorders | Delusional disorder

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders Delusional disorder, in partial remission • The full diagnostic requirements for delusional disorder have not been met within the past month, but some clinically significant symptoms remain, which may or may not be associated with functional impairment. Note: this category may also be used to designate the re-emergence of subthreshold symptoms of delusional disorder following an asymptomatic period in a person who has previously met the diagnostic requirements for delusional disorder. Delusional disorder, in full remission • The full diagnostic requirements for delusional disorder have not been met within the past month, and no clinically significant symptoms remain. Delusional disorder, unspecified Additional clinical features • Delusions may be accompanied by actions directly related to the content of the delusions – for example, stalking the loved person in the context of erotomania or filing lawsuits against those believed to be persecuting the person. • Rarely, delusional disorder may occur at the same time (or closely associated in time) in two people who have a strong emotional or situational link. This condition is often referred to as “shared or induced delusional disorder” or “folie-à-deux”. In such cases, one person typically adopts the delusional belief of the other person, and the delusions may remit in the less dominant person when the two individuals are separated. Boundary with normality (threshold) • A continuum of delusional beliefs, attenuated delusional beliefs, overvalued ideas, and unusual or eccentric beliefs has been observed in the general population. Such beliefs may be more common among people under conditions of adversity. People with delusional disorder may display greater psychological distress, greater preoccupation and a higher degree of conviction compared to people in the general population with beliefs that are similar in nature to beliefs that could be characterized as delusional. 6A24.1 6A24.2 6A24.Z Schizophrenia and other primary psychotic disorders | Delusional disorder

187 Schizophrenia and other primary psychotic disorders Course features • Delusional disorder typically has a later onset and greater stability of symptoms than other psychotic disorders with delusional symptoms. • Some individuals with delusional disorder will develop schizophrenia. • Individuals are more likely to have a premorbid personality disorder prior to the onset of delusional disorder. • Levels of functioning are typically better among individuals with delusional disorder compared to those with a diagnosis of schizophrenia or another primary psychotic disorder. • Individuals with delusional disorder are less likely to require hospitalization in comparison to individuals with either schizophrenia or schizoaffective disorder. Developmental presentations • Delusional disorder is more prevalent among older individuals. • Individuals who experience delusional disorder in early adulthood are more likely to have a history of hallucinations and severe psychopathology during adolescence. Culture-related features • Cultural factors may influence the presentation and diagnosis of delusional disorder. For example, spirit possession or witchcraft beliefs may be normative in some but not other cultures. • Individuals may present with a combination of delusions and overvalued ideas, both drawing on similar cultural idioms and beliefs. • Diverse populations that experience persecution (e.g. torture, political violence, discrimination due to minority status) may report fears that may be misjudged as paranoid delusions; these may represent instead appropriate fears of recurrence of being persecuted or symptoms of co-occurring post-traumatic stress disorder. Accurate diagnosis relies on obtaining historical information and considering the cultural context to discern the veracity of persecutory beliefs. Schizophrenia and other primary psychotic disorders | Delusional disorder

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders Sex- and/or gender-related features • There are no prominent gender differences in delusional disorder. However, males appear to have a younger age of onset and are more likely to have delusions of jealousy. Boundaries with other disorders and conditions (differential diagnosis) Boundary with schizophrenia Both schizophrenia and delusional disorder may be characterized by persistent delusions. If other features are present that meet the diagnostic requirements for schizophrenia (i.e. persistent hallucinations, disorganized thinking, negative symptoms, disorganized or abnormal psychomotor behaviour, or experiences of influence, passivity or control), a diagnosis of schizophrenia may be made instead of a diagnosis of delusional disorder. However, hallucinations that are consistent with the content of the delusions and do not occur persistently (i.e. with regular frequency for 1 month or longer) are consistent with a diagnosis of delusional disorder rather than schizophrenia. Delusional disorder is generally characterized by relatively preserved personality and less deterioration and impairment in social and occupational functioning than schizophrenia, and individuals with delusional disorder tend to present for the first time at a later age. Individuals with symptom presentations consistent with delusional disorder (e.g. delusions and related, circumscribed hallucinations) but who have not met the minimum duration requirement of 3 months should not be assigned a diagnosis of schizophrenia, even though the combination of persistent delusions and related hallucinations technically meets diagnostic requirements for schizophrenia. Instead, a diagnosis of other specified primary psychotic disorder is more appropriate in such cases. Boundary with mood disorders with psychotic symptoms In depressive disorders with psychotic symptoms and bipolar disorders with psychotic symptoms, delusions may present during the course of the mood episodes. Although mood symptoms – especially depressed mood – can occur in delusional disorder, the diagnosis of delusional disorder requires that there are times when the person experiences the delusions in the absence of any mood disturbance. Boundary with obsessive-compulsive disorder, body dysmorphic disorder, hypochondriasis (health anxiety disorder), olfactory reference disorder and anorexia nervosa A number of mental disorders (e.g. obsessive-compulsive disorder, body dysmorphic disorder, hypochondriasis, olfactory reference disorder, anorexia nervosa) may involve a recurrent preoccupation with a belief that is demonstrably untrue or that is not shared by others (e.g. that ritualistically washing one’s hands prevents harm to loved ones, that a body part is defective, that one has a serious medical illness, that one emits a foul smell, that one is overweight) that may at times appear to be delusional in intensity, in the context of the other clinical features of that disorder. An additional diagnosis of delusional disorder should not be given if the belief occurs entirely in the context of symptomatic episodes of one of these other disorders and is fully consistent with its other clinical features. Schizophrenia and other primary psychotic disorders | Delusional disorder