Schizophrenia

Schizophrenia is a mental disorder characterized by the presence of positive symptoms (delusions, hallucinations), isorganization, and negative symptoms (poverty of thought, amotivation). It is important to recognize that schizophrenia itself likely is not a single disease entity with a single cause, but rather a syndromal disorder with a variety of etiologies. That is, the symptoms overlap with other psychotic disorders. Each patient with a diagnosis of schizophrenia will present with a different set of symptoms, under the current diagnostic paradigms in the DSM and ICD.

Prevalence
Risk Factors
Criterion A

At least 2 of the following, each present for a significant portion of time during a 1-month period (or less if successfully treated). At least 1 of these must be (1), (2), or (3):

  1. Delusions
  2. Hallucinations
  3. Disorganized speech (e.g., frequent derailment or incoherence)
  4. Grossly disorganized or catatonic behaviour
  5. Negative symptoms (i.e., diminished emotional expression or avolition)
Criterion B

For a significant portion of the time since the onset of the disturbance, level of functioning in at least 1 major area, such as work, interpersonal relations, or self-care, is markedly below the level achieved prior to the onset (or when the onset is in childhood or adolescence, there is failure to achieve expected level of interpersonal, academic, or occupational functioning).

Criterion C

Continuous signs of the disturbance persist for at least 6 months. This 6-month period must include at least 1 month of symptoms (or less if successfully treated) that meet Criterion A (i.e., active-phase symptoms) and may include periods of prodromal or residual symptoms. During these prodromal or residual periods, the signs of the disturbance may be manifested by only negative symptoms or by 2 or more symptoms listed in Criterion A present in an attenuated form (e.g., odd beliefs, unusual perceptual experiences).

Criterion D

Schizoaffective disorder and depressive or bipolar disorder with psychotic features have been ruled out because either:

  1. No major depressive or manic episodes have occurred concurrently with the active-phase symptoms, or
  2. If mood episodes have occurred during active-phase symptoms, they have been present for a minority of the total duration of the active and residual periods of the illness.
Criterion E

The disturbance is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition.

Criterion F

If there is a history of autism spectrum disorder or a communication disorder of child hood onset, the additional diagnosis of schizophrenia is made only if prominent delusions or hallucinations, in addition to the other required symptoms of schizophrenia, are also present for at least 1 month (or less if successfully treated).

Specifiers

Specifiers

Specify if: First episode, currently in acute episode: First manifestation of the disorder meeting the defining diagnostic symptom and time criteria. An acute episode is a time period in which the symptom criteria are fulfilled.

  • First episode, currently in partial remission: Partial remission is a period of time during which an improvement after a previous episode is maintained and in which the defining criteria of the disorder are only partially fulfilled.
  • First episode, currently in full remission: Full remission is a period of time after a previous episode during which no disorder-specific symptoms are present.
  • Multiple episodes, currently in acute episode: Multiple episodes may be deter mined after a minimum of two episodes (i.e., after a first episode, a remission and a minimum of one relapse).
  • Multiple episodes, currently in partial remission
  • Multiple episodes, currently in full remission
  • Continuous: Symptoms fulfilling the diagnostic symptom criteria of the disorder are remaining for the majority of the illness course, with subthreshold symptom periods be ing very brief relative to the overall course.
  • Unspecified

Severity Specifier

Specify if:

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

              Various scales can be used to measure schizophrenia symptoms in an individual. Below are the most common ones, with an indication for each.

              Psychometric Scales for Schizophrenia

              Positive and Negative Syndrome Scale (PANSS)
              Rater Clinician
              Description The patient is rated from 1 to 7 on 30 different symptoms based on the interview as well as reports of family members or primary care hospital workers. It is a 45-minute clinical interview.
              Download PANSS Download
              Name Rater Description Download
              Positive and Negative Syndrome Scale (PANSS) Clinician The patient is rated from 1 to 7 on 30 different symptoms based on the interview as well as reports of family members or primary care hospital workers. It is a 45-minute clinical interview. PANSS Download

              One theory in the pathophysiology of schizophrenia is that an increase dopamine activity causes the positive symptoms of schizophrenia. Similar to how methamphetamine and cocaine also increases dopamine activity, and can cause schizophrenia-like symptoms. Therefore, antipsychotics target the mesolimbic pathway to decrease the incidence of positive symptoms. Antipsychotics work by binding to dopaminergic neuroreceptors. It is important to keep in mind that this is a theoretical model, and that the pathophysiology of schizophrenia remains poorly understood. See

              Research

              The latest research suggests that synaptic pruning, i.e. - global neuronal dysfunction, is responsible for the development of schizophrenia.[1] Sensory prediction deficits is also another theory of why psychotic symptoms develop, and why individuals with schizotypal personalities are more likely to be able to tickle themselves, compared to the general population.[2] Other theories include the HPA axis and endocrine disruption.[3]

              Medication

              Antipsychotics are considered the gold-standard of treatment.

              Before labelling patients treatment resistant, it is important to recognize that many patients may be on sub-therapeutic levels of antipsychotics.[4]

              Benzodiazepines can be prescribed for short-term management of acute agitation, but should not be used as long-term pharmacotherapy as it increases all-cause mortality.[5][6]

              Psychotherapy

              ECT

              First-Episode Psychosis

              Comprehensive care for first episode psychosis and improves functional and clinical outcomes. Effects are more pronounced for those with shorter duration of untreated psychosis.[7]

              Assertive Community Treatment

              References