Depression and Schizophrenia: Cause, Consequence or Trans-diagnostic Issue?

The presence of depression in schizophrenia has been a challenge to the Kraepelinian dichotomy, with various attempts to save the fundamental distinction including evoking and refining diagnoses such as schizoaffective disorder. But the tectonic plates are shifting. Here we put forward a summary of recent evidence regarding the prevalence, importance, possible aetiological pathways and treatment challenges that recognizing depression in schizophrenia bring. Taken together we propose that depression is more than comorbidity and that increased effective therapeutic attention to mood symptoms will be needed to improve outcomes and to support prevention.