Insomnia symptoms are associated with metabolic syndrome in patients with severe psychiatric disorders

Objective: To examine the relationship between insomnia symptoms and metabolic syndrome in patients with severe psychiatric disorders.

Methods: We conducted a cross-sectional study including 272 inpatients (mean age: 34.06 ± 11.52 years, 67.3% males) with severe psychiatric disorders consecutively admitted in Shantou University Mental Health Center Inpatient Department. All patients underwent a psychiatric evaluation. Insomnia symptoms were assessed by the Pittsburgh Sleep Quality Index (PSQI) and defined present if PSQI>7. The diagnosis of metabolic syndrome was defined using the new International Diabetes Federation definition based on clinical and laboratory evaluation.

Results: Among the 272 patients, 94 (34.6%) presented insomnia symptoms. Overall, patients with insomnia symptoms had significantly higher percentage of metabolic syndrome (23.4% vs. 12.4%, p = 0.019) and hypertriglyceridemia (30.9% vs. 19.1%, p = 0.029), and marginally significantly higher levels of fasting insulin (58.75 ± 37.22 pmol/L vs. 51.72 ± 34.09 pmol/L, p = 0.050), homeostasis model assessment of insulin resistance (1.83 ± 1.31 vs. 1.62 ± 1.25, p = 0.055) and percentage of insulin resistance (55.3% vs. 44.4%, p = 0.086) compared to those without insomnia symptoms. Multiple logistic regressions showed that patients with insomnia symptoms had significantly higher odds for metabolic syndrome [odds ratio (OR) = 2.99, 95% confidence interval (CI) = 1.25-7.14], central obesity (OR = 3.02, 95% CI = 1.18-7.76), hypertriglyceridemia (OR = 2.46, 95% CI = 1.28-4.76) and marginally significantly higher odds for insulin resistance (OR = 1.68, 95% CI = 0.93-3.02) after controlling for potential confounders.

Conclusions: Within severely mentally ill patients, insomnia symptoms are associated with metabolic syndrome and insulin resistance. It appears that insomnia symptoms are independent clinical indicators of underlying metabolic syndrome in patients with severe psychiatric disorders.