Depressive psychopathology in first-episode schizophrenia spectrum disorders: a systematic review, meta-analysis and meta-regression.

At least one-quarter of individuals with FES will experience, and therefore require treatment for, a full-threshold depressive disorder. Nearly half will experience levels of depressive symptoms that are severe enough to warrant diagnostic investigation and therefore clinical intervention - regardless of whether they actually fulfil diagnostic criteria for a depressive disorder. Depressive psychopathology is prominent in FES, manifesting not only as superimposed comorbidity, but also as an inextricable symptom domain.