Boundaries of Schizoaffective Disorder

Abstract

IMPORTANCE Established nosology identifies schizoaffective disorder as a distinct category with boundaries separating it from mood disorders with psychosis and from schizophrenia. Alternative models argue for a single boundary distinguishing mood disorders with psychosis from schizophrenia (kraepelinian dichotomy) or a continuous spectrum from affective to nonaffective psychosis. OBJECTIVE To identify natural boundaries within psychotic disorders by evaluating associations between symptom course and long-term outcome. DESIGN, SETTING, AND PARTICIPANTS The Suffolk County Mental Health Project cohort consists of first-admission patients with psychosis recruited from all inpatient units of Suffolk County, New York (72% response rate). In an inception cohort design, participants were monitored closely for 4 years after admission, and their symptom course was charted for 526 individuals; 10-year outcome was obtained for 413. MAIN OUTCOMES AND MEASURES Global Assessment of Functioning (GAF) and other consensus ratings of study psychiatrists. RESULTS We used nonlinear modeling (locally weighted scatterplot smoothing and spline regression) to examine links between 4-year symptom variables (ratio of nonaffective psychosis to mood disturbance, duration of mania/hypomania, depression, and psychosis) and 10-year outcomes. Nonaffective psychosis ratio exhibited a sharp discontinuity-10 days or more of psychosis outside mood episodes predicted an 11-point decrement in GAF-consistent with the kraepelinian dichotomy. Duration of mania/hypomania showed 2 discontinuities demarcating 3 groups: mania absent, episodic mania, and chronic mania (manic/hypomanic >1 year). The episodic group had a better outcome compared with the mania absent and chronic mania groups (12-point and 8-point difference on GAF). Duration of depression and psychosis had linear associations with worse outcome. CONCLUSIONS AND RELEVANCE Our data support the kraepelinian dichotomy, although the study requires replication. A boundary between schizoaffective disorder and schizophrenia was not observed, which casts further doubt on schizoaffective diagnosis. Co-occurring schizophrenia and mood disorder may be better coded as separate diagnoses, an approach that could simplify diagnosis, improve its reliability, and align it with the natural taxonomy.

Disconnection Between Amygdala and Medial Prefrontal Cortex in Psychotic Disorders

“…The SCZ group included 16 individuals with SCZ and 10 individuals with schizoaffective disorder. These 2 diagnoses were combined based on previous work in our cohort, 68,69 as well as other work 70,71 showing that schizoaffective disorder and SCZ are very similar and characterized by more severe symptoms, worse course, and greater cognitive impairment than other psychotic disorders. People with schizoaffective disorder experience substantial burden of mood symptoms, which overlaps with bipolar disorder to some degree.…”

“…72,73 With regard to cognitive functioning and long-term outcome, schizoaffective disorder in this cohort is qualitatively different from mood disorder with psychosis but indistinguishable from SCZ. 68,69 CON, the comparison group of age and gender matched individuals with no history of psychosis was selected from the same neighborhoods as the cases.…”

Neuropsychological and Brain Functional Changes Across the Different Phases of Schizoaffective Disorder

“…Kotov et al (2013) employed a statistical technique, nonlinear modelling, to examine for presence of discontinuities in outcome among different forms of psychosis. They followed up 413 psychotic inpatients over ten years, rating presence of symptoms, numbers of affective and psychotic episodes, and also functioning using the Global Assessment of Functioning (GAF) scale.…”

Emotional awareness and delusions in schizophrenia and schizoaffective disorder

“…Although there has been a great deal of debate regarding the validity of schizoaffective disorder as a mental disorder that is distinct from schizophrenia [27], a large number of individuals with psychotic disorders currently receive the diagnosis [28] and at least some studies suggest the distinction may be valid [e.g., 29]. Regardless of the ultimate fate of schizoaffective disorder as a distinct diagnostic entity, it remains the case that a modest proportion of individuals who would otherwise meet the diagnostic criteria for schizophrenia have a history of co-occurring mood disorder and schizophrenia symptoms.…”