Associations between metabolic disorders and sleep disturbance in patients with schizophrenia

Sleep disturbance plays a crucial role in mental illness and metabolic dysregulation. However, the clinical correlates of metabolic disorders (MD, only meeting 1 or 2 metabolic syndrome standards) and its relationship to sleep disturbance in patients with schizophrenia are uncertain. The study was to illuminate the association between MD and sleep disturbance in patients with schizophrenia.

One hundred and sixty-four patients with schizophrenia (157 drug-naive and 7 drug-free) were classified into 2 groups: MD and non-MD. The Pittsburgh Sleep Quality Index (PSQI) and the Positive and Negative Symptom Scale (PANSS) were employed to assess sleep quality and clinical symptoms. Weight, height, waistline, blood pressure, fasting glucose, and lipid metabolic levels were recorded.

Sleep disturbance was more pronounced in the MD group compared to the non-MD group, including subjective sleep quality (z = -4.074, p = 0.000), sleep latency (z = -3.867, p = 0.000), sleep duration (z = -2.471, p = 0.013) and total scores (z = -3.074, p = 0.002). After controlling for confounding factors including age, sex, body mass index, smoking, marital status, and duration of illness, binary logistics regression showed that subjective sleep quality (p = 0.034) and sleep latency (p = 0.034) were significant independent predictors of MD. Further, partial correlation analysis showed that sleep latency (r = -0.200, p = 0.011) was significantly negatively correlated with HDLC.

Our study suggests a high rate of MD in patients with schizophrenia, most of who were drug-naive, in a Chinese population. Longer sleep latency is associated with MD in schizophrenia patients, suggesting an important role of sleep disturbance in the development of MD in patients with schizophrenia. Interventions to improve sleep quality may prevent MD in patients with schizophrenia at an early stage.