Depression in Schizophrenia – Causes, Importance and Treatment
Depression occurs commonly in schizophrenia and first-episode psychosis (FEP) and challenges the Kraepelinian Dichotomy between bipolar disorder and schizophrenia.
In the clinically high-risk phase where individuals may be in the prodrome of developing a psychotic episode, depression occurs in approximately 40% of people.
The close linkage between psychosis symptoms and depression, especially in the prodromal phase has led to proposals that depression in schizophrenia may be the severe end of a dimension of affective dysregulation beginning in adolescence progressing into the early stages of psychosis as the illness crystalizes. [Upthegrove R et al., 2017]
In acute episodes rates of depression are up to 60%, while in post-psychotic schizophrenia rates of moderate to severe depression varies between 20% in chronic schizophrenia and 50% following treatment of the first episode.
Depression has been linked to increased risk of transition from Ultra High Risk (UHR) to first-episode psychosis (FEP). Transition rates in clinical high-risk groups are between 16-20%, and in people who do not transition to FEP, depression, and Axis I disorders are highly prevalent. [Beck et al. 2019]