What are the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) criteria for diagnosing schizoaffective disorder?

DSM-5-TR Criteria for Schizoaffective Disorder

Schizoaffective disorder requires meeting criteria for both mood episodes and schizophrenia, with psychotic symptoms persisting for at least two weeks in the absence of prominent mood symptoms. 1

Core Diagnostic Criteria

A. Primary Requirements

• An uninterrupted period of illness during which there is a major mood episode (major depressive or manic) concurrent with Criterion A of schizophrenia
• Delusions or hallucinations must be present for at least 2 weeks in the absence of a major mood episode during the lifetime duration of the illness 2
• Symptoms that meet criteria for a major mood episode must be present for the majority of the total duration of the active and residual portions of the illness 2

B. Exclusion Criteria

• The disturbance is not attributable to the effects of a substance (drug of abuse or medication) or another medical condition
• The symptoms are not better explained by another mental disorder

Subtypes

• Bipolar type: If the disturbance includes a manic episode (may also include major depressive episodes)
• Depressive type: If the disturbance only includes major depressive episodes 1

Key Diagnostic Features and Changes in DSM-5-TR

1. Lifetime Perspective: DSM-5-TR shifted from an episode-based diagnosis to a life-course illness assessment 2

2. Temporal Relationship:

   • Mood symptoms must be present for the majority of the total illness duration
   • Psychotic symptoms must persist for at least 2 weeks in the absence of prominent mood symptoms 2

3. Differential Diagnosis:

   • If psychotic symptoms occur exclusively during mood episodes: diagnose as Mood Disorder with Psychotic Features
   • If psychotic symptoms persist outside mood episodes for at least 2 weeks: diagnose as Schizoaffective Disorder or Schizophrenia 2

Clinical Implications

• The diagnostic reliability of schizoaffective disorder has historically been poor (Cohen's kappa as low as 0.22) 3
• DSM-5-TR criteria aim to improve reliability by providing more specific requirements 2
• The diagnosis requires careful longitudinal assessment to accurately determine the relationship between psychotic and mood symptoms over time

Diagnostic Challenges

• Distinguishing schizoaffective disorder from schizophrenia with mood symptoms and from severe mood disorders with psychotic features remains difficult 4
• Some researchers have questioned whether schizoaffective disorder represents a distinct entity or rather exists on a continuum between schizophrenia and mood disorders 5, 6
• The requirement for psychotic symptoms to persist for at least 2 weeks without prominent mood symptoms helps differentiate from mood disorders with psychotic features

Clinical Course and Prognosis

• Typically combines the social/occupational dysfunction seen in schizophrenia with mood instability 1
• Generally has a better outcome than schizophrenia but worse than mood disorders 3
• Often requires combination treatment with both antipsychotics and mood stabilizers 1

Common Pitfalls in Diagnosis

• Failing to document the presence of psychotic symptoms outside of mood episodes
• Not assessing the total duration of mood symptoms relative to the entire illness course
• Overdiagnosis due to inadequate longitudinal assessment
• Confusing schizoaffective disorder with substance-induced psychotic disorder

The DSM-5-TR criteria aim to reduce rates of diagnosis of schizoaffective disorder while increasing diagnostic stability once the diagnosis is made, by providing clearer boundaries between schizophrenia with mood symptoms and schizoaffective disorder 2.