Delusional Disorder

Delusional disorder is a mental disorder characterized by the presence of one or more delusions that persist for at least 1 month. A diagnosis of delusional disorder is not given if the individual has ever had a symptoms of schizophrenia. Apart from the direct impact of the delusions, impairments in psychosocial functioning may be more circumscribed than those seen in other psychotic disorders such as schizophrenia, and behaviour is not obviously bizarre or odd.

Prevalence

The lifetime prevalence of delusional disorder has been estimated at around 0.2%, and the most frequent subtype is persecutory. Delusional disorder, jealous type, is probably more common in males than in females, but there are no major gender differences in the overall frequency of delusional disorder.

Criterion A

The presence of at least 1 delusion with a duration of at least 1 month.

Criterion B

Criterion A for schizophrenia has never been met.

Note: Hallucinations, if present, are not prominent and are related to the delusional theme (e.g., the sensation of being infested with insects associated with delusions of infestation).
Criterion C

Apart from the impact of the delusion(s) or its ramifications, functioning is not markedly impaired, and behaviour is not obviously bizarre or odd.

Criterion D

If manic or major depressive episodes have occurred, these have been brief relative to the duration of the delusional periods.

Criterion E

The disturbance is not attributable to the physiological effects of a substance or an other medical condition and is not better explained by another mental disorder, such as body dysmorphic disorder or obsessive-compulsive disorder.

Specifiers

Specifiers

Specify whether:

  • Erotomanic type: This subtype applies when the central theme of the delusion is that another person is in love with the individual.
  • Grandiose type: This subtype applies when the central theme of the delusion is the conviction of having some great (but unrecognized) talent or insight or having made some important discovery.
  • Jeaious type: This subtype applies when the central theme of the individual’s delusion is that his or her spouse or lover is unfaithful.
  • Persecutory type: This subtype applies when the central theme of the delusion in volves the individual’s belief that he or she is being conspired against, cheated, spied on, followed, poisoned or drugged, maliciously maligned, harassed, or obstructed in the pursuit of long-term goals.
  • Somatic type: This subtype applies when the central theme of the delusion involves bodily functions or sensations.
  • Mixed type: This subtype applies when no one delusional theme predominates.
  • Unspecified type: This subtype applies when the dominant delusional belief cannot be clearly determined or is not described in the specific types (e.g., referential delusions without a prominent persecutory or grandiose component).
  • With bizarre content: Delusions are deemed bizarre if they are clearly implausible, not understandable, and not derived from ordinary life experiences (e.g., an individual’s belief that a stranger has removed his or her internal organs and replaced them with some one else’s organs without leaving any wounds or scars).

Severity Specifier

Specify current severity:

  • Severity is rated by a quantitative assessment of the primary symptoms of psychosis, including delusions, hallucinations, disorganized speech, abnormal psychomotor be havior, and negative symptoms. Each of these symptoms may be rated for its current severity (most severe in the last 7 days) on a 5-point scale ranging from 0 (not present) to 4 (present and severe)
  • Note: Diagnosis of delusional disorder can be made without using this severity specifier

Delusional disorder is highly resistant to treatment with medication alone.[1]

What is psychosis?

The term psychosis has been defined in various ways in the medical literature over time. The narrowest and current definition of psychosis is hallucinations and delusions, with the lack of reality testing or insight. A broader definition of psychosis would also include disorganized thought, emotions, and behaviour. This loose definition was more common in the past, and schizophrenia was often overdiagnosed as a result.

Comparison

Brief psychotic disorder
Onset Sudden
Length 1 day to 1 month
Psychotic Symptoms At least 1 of:
  • Delusions
  • Hallucinations
  • Disorganized speech
  • Grossly disorganized or catatonic behaviour
    Mood Symptoms No
    Functional Decline? Full resolution of symptoms
    Schizophreniform disorder
    Onset Can be prodromal
    Length 1 month to 6 months
    Psychotic Symptoms At least 2 of:
    • Delusions
    • Hallucinations
    • Disorganized speech
    • Grossly disorganized or catatonic behaviour
    • Negative symptoms
      Mood Symptoms No
      Functional Decline? Not required
      Schizophrenia
      Onset Can be prodromal
      Length > 6 months
      Psychotic Symptoms
      Mood Symptoms No
      Functional Decline? Required
      Schizoaffective disorder
      Onset Can be prodromal
      Length Major mood episode
      + 2 weeks of psychotic symptoms
      Psychotic Symptoms
      • Delusions or hallucinations for 2 or more weeks
      • Must be in absence of a major mood episode (depressive or manic) during the lifetime duration of the illness
        Mood Symptoms Required
        Functional Decline? Not required
        Delusional disorder
        Onset Can be prodromal
        Length > 1 month
        Psychotic Symptoms One or more delusions, with no other psychotic symptoms.
        Mood Symptoms No
        Functional Decline? Normal function aside from impact of delusions
        Type Onset Length Psychotic Symptoms Mood Symptoms Functional Decline?
        Brief psychotic disorder Sudden 1 day to 1 month At least 1 of:
        • Delusions
        • Hallucinations
        • Disorganized speech
        • Grossly disorganized or catatonic behaviour
          No Full resolution of symptoms
          Schizophreniform disorder Can be prodromal 1 month to 6 months At least 2 of:
          • Delusions
          • Hallucinations
          • Disorganized speech
          • Grossly disorganized or catatonic behaviour
          • Negative symptoms
            No Not required
            Schizophrenia Can be prodromal > 6 months No Required
            Schizoaffective disorder Can be prodromal Major mood episode
            + 2 weeks of psychotic symptoms
            • Delusions or hallucinations for 2 or more weeks
            • Must be in absence of a major mood episode (depressive or manic) during the lifetime duration of the illness
              Required Not required
              Delusional disorder Can be prodromal > 1 month One or more delusions, with no other psychotic symptoms. No Normal function aside from impact of delusions
              References