Striatum volume and affective symptomatology are associated with sleep in schizophrenia

Sleep dysfunction is common among individuals with schizophrenia spectrum disorders (SSD). Sleep duration and other sleep quality metrics are associated with worse patient clinical and social outcomes. We examined if accumulative stress, gray matter structural volume measured with high-resolution structural brain MRI, diffusion tensor imaging measures of white matter microstructure, and psychopathology (for the schizophrenia group) may act as predictors of sleep quality and compared individuals with SSD (N = 101) and healthy controls (N = 86). We created an adjusted Pittsburgh Sleep Quality Index (PSQI-A) score to measure sleep quality and account for abnormally long sleep duration as dysfunctional. The SSD group reported significantly poorer sleep on most dimensions measured, and 33% of SSD subjects reported sleeping more than 9 h. Hierarchical multiple regression with four blocks (age and sex; number of major life events within the last ten years/accumulative stress; Affect and Positive Symptom subscales of the Brief Psychiatric Rating Scale (BPRS); and striatum and pallidum volume) accounted for 28 % of the variance in sleep quality for the SSD group. Negative affective symptoms (β = .335, p = .003) and dorsal striatal volume (β = -.287, p = .004) remained significant predictors of sleep quality in the final model, indicating that higher severity of negative affect and lower striatal volume predict worse sleep quality. Results have several implications for treatment targets and are hypothesis-generating for future research aims.