Table 1

Schizophrenia and psychotic disorders2

Schizophrenia
  • At least two of the following five features (at least one of which must be one of the first three): delusions; hallucinations; disorganised speech; marked behavioural disturbance; negative symptoms such as diminished emotional expression or avolition.

  • Marked deterioration in functioning.

  • Continuous signs of the disturbance for at least 6 months.

  • Associated features may support the diagnosis:

    • Inappropriate affect such as laughing in the absence of an appropriate stimulus.

    • Dysphoric mood with anxiety, anger or depression.

    • Cognitive deficits (which are strongly linked to functional impairments), for example, in memory, language and executive functions.

    • Deficits in social cognition, for example, inability to infer the intentions of others.

Delusional disorder
  • One or more delusions for at least 1 month.

  • Hallucinations are not prominent and if present relate to the delusional theme (eg, sensations of insect infestation when delusions are of infestation).

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

Brief psychotic disorder
  • Symptoms of at least one of the following: delusions; hallucinations; disorganised speech. Disorganised behaviour may or may not be present.

  • Duration between 1 day and 1 month.

  • Level of impairment may be severe but eventually return to full functioning.

  • May occur in response to a severe stressor (and then sometimes called brief reactive psychosis).

Schizophreniform disorder
  • Characteristic symptoms identical to schizophrenia (at least two of five features, at least one of which must be one of the first three).

  • Shorter duration (1–6 months).

  • May be a provisional diagnosis, that is, when the patient still has ongoing symptoms but it has not yet been 6 months.

Schizoaffective disorder
  • An uninterrupted period of the illness during which there is a major mood episode (major depressive or manic) concurrent with at least two of the five features of schizophrenia.

  • Delusions or hallucinations for 2 or more weeks in the absence of a major mood episode during the lifetime of the illness.

  • Symptoms meeting criteria for a major mood episode are present for the majority of the total duration of the active and residual portions of the illness.

  • Classified as bipolar type if any manic episodes have occurred and depressive type if mood episodes have been exclusively depressive.

Psychotic disorder due to another medical condition
  • Prominent delusions or hallucinations with significant distress or functional impairment.

  • Evidence via history, examination or laboratory findings that symptoms are the direct pathophysiological consequence of the medical condition.

  • Symptoms not better explained by another mental disorder or by delirium.

Substance/medication-induced psychotic disorder
  • Delusions and/or hallucinations with significant distress or functional impairment.

  • Symptoms emerge during or soon after substance intoxication or withdrawal (per evidence from history, examination or laboratory findings).

  • The substance is known to be capable of producing delusions and/or hallucinations.

  • Symptoms not better explained by another psychotic disorder or by delirium.

Attenuated psychosis syndrome (included in the DSM-5 as a Condition for Further Study)
  • Must have one of the following at least once per week for the past month: delusions; hallucinations; disorganised speech.

  • Symptoms are distressing and disabling.

  • Symptoms are below threshold for diagnosis of any other psychotic disorder (eg, less severe and/or more transient).

  • DSM-5, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.