Contributions of Sleep Quality and Dissociation to Attenuated Positive Psychotic Symptom Severity

Abstract

Sleep disturbances have been observed across the entire psychosis spectrum. Research has begun to focus on the clinical high risk (CHR) period for psychosis, as the presence of sleep disturbance can be examined separately from the effects of antipsychotic medication and is potentially a risk factor for later psychosis. Several studies have demonstrated a link between sleep disturbance and worsened positive symptoms in CHR individuals. However, sleep disturbance is not unique to the psychosis-spectrum and is well documented in individuals experiencing dissociation. Transdiagnostically, dissociation has been associated with poorer outcomes and reduced treatment response. Despite the established associations between these variables, their respective contributions to positive symptom severity in the CHR period has not yet been characterized. This study examined the separate and combined contributions of sleep quality and dissociation on positive symptom severity in a cross-sectional sample of individuals identified as being at CHR for psychosis. Hierarchical linear regression was conducted to examine the independent and additive influence of sleep quality and dissociation on unusual thought content, suspiciousness, and perceptual abnormalities. Finally, logistic regression was used to determine if sleep quality and dissociation increase odds of a CHR diagnosis. Analyses of indirect effects revealed a significant indirect effect of sleep disturbance on perceptual abnormalities through dissociation in the CHR group. In addition, both sleep disturbance and dissociation significantly contributed to a model predicting to perceptual abnormalities, also in the CHR group. In the total sample, both sleep quality and dissociation significantly increased the odds of a CHR diagnosis. These results suggest that dissociation plays a significant role in the sleep-attenuated positive psychotic symptom relationship in the CHR period, and as a result, could be a modifiable treatment target in these individuals.