Polysomnographic Parameters in Schizoaffective Disorder: A Systematic Review and Meta-Analysis

Background: Schizoaffective disorder (SZA) is a severe psychiatric condition characterized by overlapping affective and psychotic features; however, its sleep architecture remains poorly characterized. This systematic review and meta-analysis compared polysomnographic findings in drug-free patients with SZA with those of healthy controls (HC), patients with schizophrenia (SCZ), and patients with major depressive disorder (MDD). Methods: An extensive database search identified 40 studies. Nine case-control studies including 79 patients with SZA, 88 patients with SCZ, 79 HC, and 131 patients with MDD were included in the meta-analyses. Total sleep time, sleep efficiency, sleep latency, wake after sleep onset, and rapid-eye-movement (REM) and non-REM (NREM) sleep variables were analyzed. The primary outcome measure was the standardized mean difference (SMD). Data were analyzed using a random-effects model. Publication bias was assessed using Egger's regression test and funnel plot asymmetry. Results: Compared with HC, patients with SZA showed reduced total sleep time, increased sleep latency and wakefulness after sleep onset, reduced REM sleep duration, shortened REM latency, and reduced stage 4 sleep duration and percentage. Patients with SZA differed from those with MDD only in exhibiting increased sleep latency, whereas no significant differences were observed between patients with SZA and those with SCZ. Conclusions: Polysomnographic abnormalities in SZA demonstrate a general pattern of sleep disruption compared with HC, without clear differentiation from SCZ or MDD. Overall, current evidence does not support sleep architecture as a reliable biomarker for distinguishing SZA from related psychotic or affective disorders. These findings should be considered exploratory, given the small sample sizes, limited number of available studies, and substantial heterogeneity across studies. Further research is needed to determine whether specific sleep measures may better distinguish SZA from other psychiatric conditions.