BACKGROUND: Patients with psychotic disorders show higher rates of the metabolic syndrome (MS) between the cluster of severe mental illnesses. Depressive symptoms can worsen outcomes of individuals with psychotic disorders. However, research on the association between MS and depression in psychotic disorders and their relevance to outcomes is lacking.
METHODS: We investigated the association between depression and cardiometabolic biomarkers in psychotic disorders and the predictive value of depressive symptoms on psychopathological severity and quality of life (QoL). 406 patients with psychotic disorders were recruited as part of the Improving Physical Health and Reducing Substance Use in Severe Mental Illness randomised controlled trial. Depression, psychotic symptoms, QoL, waist circumference, triglycerides, high-density lipoprotein cholesterol (HDL-C), blood pressure, and fasting glucose of patients were assessed at baseline and 12 months. Sensitivity analyses were conducted to test the effect of treatment.
RESULTS: More severe baseline symptoms of depression significantly predicted worse 12-month psychotic symptoms and lower mental health related QoL at 12 months. These associations held after controlling for alcohol use, gender, ethnicity, education, and mental health related QoL Baseline. Depressive symptoms also correlated with waist circumference at both baseline and 12 months, after controlling for multiple testing.
CONCLUSION: Individuals with psychotic disorders experiencing more severe depressive symptoms are more likely to have larger waist circumference contemporaneously and 12 months later, as well as more severe psychotic symptoms and worse QoL at follow-up. This highlights the need for evaluation of strategies to address depression in the management of psychotic disorders.