Depressive symptoms are frequent clinical features in patients with schizophrenia. Depression is associated with a less favorable patient course and outcomes compared to patients with schizophrenia without depression.
The diagnosis of depression in schizophrenia is complicated by a differential diagnosis that includes depression-like extrapyramidal symptoms of antipsychotic drugs, negative symptoms of schizophrenia, and organic conditions. In addition to thorough assessment, treatment trials can be used to differentiate these conditions.
The epidemiology, clinical manifestations, diagnosis, and treatment of depression in patients with schizophrenia are discussed here. Depression and schizophrenia as individual, non-comorbid disorders are discussed separately. Other common comorbidities of schizophrenia are also discussed separately. (See "Schizophrenia: Clinical manifestations, course, assessment, and diagnosis" and "Pharmacotherapy for schizophrenia: Acute and maintenance phase treatment" and "Unipolar depression in adults: Epidemiology, pathogenesis, and neurobiology" and "Clinical manifestations and diagnosis of depression" and "Unipolar major depression in adults: Choosing initial treatment" and "Co-occurring schizophrenia and substance use disorder: Epidemiology, pathogenesis, clinical manifestations, and diagnosis" and "Anxiety in schizophrenia" and "Unipolar depression in adults: Course of illness".)
Estimates of the lifetime prevalence of depression in schizophrenia vary widely — from 6 to 75 percent — based on differing study characteristics including varying definitions of depression, patient settings, and durations of observation [1-4]. Overall, studies have found a modal prevalence of approximately 25 percent, well above the rate of depression in the general population. (See "Unipolar depression in adults: Epidemiology, pathogenesis, and neurobiology".)
Risk factors for depression in schizophrenia include family history of depressive disorder , high levels of family and personal expectations for success in life, critical family attitudes, high levels of family expressed emotion, stigma, intelligence and insight, multiple hospitalizations, recent hospital discharge, and lack or loss of psychosocial support or support of self-esteem.