Schizoaffective Disorder

Schizoaffective disorder is a mental disorder characterized by a major mood episode (either manic or depressive) that co-occurs at the same time with symptoms of schizophrenia.

Epidemiology

There are limited studies on the prevalence of schizoaffective disorder. It is estimated that 30% of cases occur between the ages of 25 and 35, and it occurs more frequently in women than men.[1][2] There is an estimate lifetime prevalence of 0.3%.[3]

Prognosis

Prognostic studies have been difficult due to the diagnostic challenges associated with schizoaffective disorder. One study found that 50% of cases showed favourable outcomes (i.e. - minimal symptoms, no symptoms, and/or employment).[4]

Comorbidity
Risk Factors

Although schizoaffective disorder is a diagnosis in the DSM-5, its validity as a diagnosis remains under debate.[5] Schizoaffective psychosis was the original term described by Russian-American psychiatrist Jacob Kasanin in 1933, and was conceptualized as an episodic illness with good outcomes.[6] This construct emerged from the Kraepelin's dichotomy of separating psychotic disorders and mood disorders, and as a “middle ground” diagnosis between schizophrenia and mood disorders. Thus, the criteria for schizoaffective disorder specifically excludes brief psychotic episodes, schizophrenia, and mood disorders with psychosis. However, even though this diagnosis attempts to draw a line to differentiate itself, the clinical reality is much different. One problem with the diagnostic criteria is it assumes that clinicians have access to longitudinal clinical data (Criterion C) (which is not always the case!). Additionally, the diagnostic entity of schizoaffective disorder has very poor inter-rater reliability between clinicians.[7] There are also cultural/stigma effects that have been noted, with clinicians preferring to use the diagnosis of schizoaffective disorder over schizophrenia.[8]

Criterion A

An uninterrupted period of illness during which there is a major mood episode (depressive or manic) concurrent with Criterion A of schizophrenia.

Note: The major depressive episode must include Criterion A1: Depressed mood.
Criterion B

Delusions or hallucinations for at least 2 weeks in the absence of a major mood episode (depressive or manic) during the lifetime duration of the illness.

Criterion C

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

Criterion D

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

Schizophrenia and affective

The key thing to remember about schizoaffective disorder is that although you need a minimum of 2 weeks of psychosis without any mood symptoms, the majority of illness time is dominated by mood symptoms – hence the name schizo (2 weeks) affective (majority) disorder.

Subtype Specifier

Specify whether:

  • Bipolar type: This subtype applies if a manic episode is part of the presentation. Major depressive episodes may also occur.
  • Depressive type: This subtype applies if only major depressive episodes are part of the presentation.

Episode Specifier

Specify if: The following course specifiers are only to be used after a 1-year duration of the disorder and if they are not in contradiction to the diagnostic course criteria.

  • 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 time period 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 determined 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 being very brief relative to the overall course.
  • Unspecified

Given its uncertainty as a diagnostic construct, schizoaffective disorder is very poorly researched in terms of understanding pathophysiology.[9] Very old studies from the 1980s suggest there are changes in dopamine, norepinephrine, and serotonin. White matter changes are also thought to be involved.[10]

    • Compared with schizophrenia, in schizoaffective disorder, there needs to be least 2 weeks in which there are only psychotic symptoms (delusions and hallucinations) and without mood symptoms. Additionally, a major mood episode (again, either depression or mania) is also present for the majority of the total duration of the illness. Once the psychotic symptoms predominate the majority of the total duration of the illness, the diagnosis would shift towards a diagnosis of schizophrenia. Also remember that schizophrenia requires 6 months of prodromal or residual symptoms, and schizoaffective disorder does not require this criterion.
    • Patients only have psychotic features during their mood episodes. In contrast, schizoaffective requires at least 2 weeks of psychotic symptoms (delusions and hallucinations) without mood symptoms. Patients also do not meet criterion A of schizoaffective disorder.
    • Similar to depression with psychotic features, patients with bipolar disorder with psychotic features only experience psychotic symptoms (delusions and hallucinations) during a manic episode. Again, schizoaffective disorder requires a period of at least 2 weeks in which there are only psychotic symptoms without mood symptoms. Again, patients also do not meet criterion A of schizoaffective disorder.

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 of Psychotic Disorders

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 At least 2 of:
• Delusions
• Hallucinations
• Disorganized speech
• Grossly disorganized or catatonic behaviour
• Negative symptoms
No Required
Schizoaffective disorder Can be prodromal Major mood episode
+ 2 weeks of isolated psychotic symptoms + predominantly mood symptoms over course of illness
• Delusions or hallucinations for 2 or more weeks, which 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

Depending on the patient's presentation, additional investigations may be ordered, including: CBC, lipids, Urine Drug Screen, TSH, infectious causes (HIV/RPR). Neuroimaging is indicated if there are any neurological deficits.