Association between depression in chronic phase and future clinical outcome of patients with schizophrenia

Rationale Depression in schizophrenia is an important symptom. We investigated whether depression and suicidal symptoms in the chronic phase are related to remote future clinical outcomes in patients with schizophrenia and whether psychotropics improved clinical outcomes. Objectives The subjects included 462 outpatients of working age (15 to 64 years old) with schizophrenia treated at Okayama University Hospital from January 2010 to December 2011. We investigated the relationship between the Clinical Global Impression-Severity score at the last visit (average 19.2 years) and the existence of previous depression, suicidal ideas, and suicide attempts. We adjusted by several possible confounders including medical history using multiple regression analysis or logistic regression analysis. Results Of 462 patients, 168 (36.4%) presented with depression 2 years after schizophrenia onset. A history of suicidal ideas and attempts was related to worse clinical outcome. In males, a history of depression was related to worse clinical outcome, but not in females. Lithium carbonate was related to better clinical outcome in all schizophrenia patients with depression, especially in males. Treatment with antidepressants was related to better clinical outcome only in males. Conclusions A history of depression or suicidal symptoms in the chronic phase predicted the future worse clinical outcome in patients with schizophrenia. The administration of lithium carbonate or antidepressants might be recommended, especially to male schizophrenia patients with depression.