Sleep disturbances in schizophrenia spectrum and bipolar disorders - a transdiagnostic perspective

Area of Science:

• Psychiatry
• Sleep Medicine
• Clinical Psychology

Background:

• Sleep disturbances are common in severe mental disorders.
• Previous large-scale studies have not extensively detailed sleep disturbance types and frequencies across different diagnostic categories.

Purpose of the Study:

• To investigate the prevalence and types of sleep disturbances in patients with schizophrenia spectrum disorders (SCZ) and bipolar disorders (BD) compared to healthy controls (HC).
• To examine the association between sleep disturbances and clinical symptoms, functioning, and treatment history in these populations.

Main Methods:

• A study including 617 patients with SCZ, 440 with BD, and 173 HC.
• Sleep disturbances (insomnia, hypersomnia, delayed sleep phase) were assessed using the Inventory of Depressive Symptoms - Clinician rated scale.
• Clinical symptoms and functioning were evaluated using the Positive and Negative Syndrome Scale and Global Assessment of Functioning scale, respectively.

Main Results:

• The prevalence of any sleep disturbance was 78% in SCZ, 69% in BD, and 39% in HC.
• Insomnia was the most frequent disturbance across all groups. Both SCZ and BD groups showed significantly higher rates of sleep disturbances than HC.
• Sleep disturbances correlated with increased negative and depressive symptoms and lower functioning, with hypersomnia linked to prior treatment history.

Conclusions:

• Sleep disturbances, encompassing insomnia, hypersomnia, and delayed sleep phase, are highly prevalent in SCZ and BD.
• These sleep issues are linked to more severe clinical symptomatology and reduced functioning, highlighting their role as a transdiagnostic phenomenon in severe mental disorders.