# Comorbid Schizophrenia and Psychotic Symptoms in Patients With Bipolar Disorder: A Meta‐Analysis of the Global Literature

## TL;DR

This study finds that while schizophrenia diagnoses in bipolar patients are rare, psychotic symptoms are common, especially in type I bipolar disorder.

## Contribution

The study provides a meta-analysis of global literature on comorbid schizophrenia and psychotic symptoms in bipolar disorder.

## Key findings

- Schizophrenia comorbidity in bipolar patients is low at 8%.
- Mood-incongruent psychosis is prevalent in 47% of bipolar patients.
- Delusions are more common than hallucinations in bipolar patients with psychosis.

## Abstract

The boundary between bipolar disorder and schizophrenia has long been blurred by the shared psychopathology, genetic risk, and social factors. This study aims to examine the prevalence of psychosis and psychotic symptoms in bipolar patients.

Key words ‘bipolar’, ‘psychosis’, ‘schizophrenia’, and the variants were searched in titles and abstracts using Medline, Psych INFO and Web of Science and forward and backward citation searches were conducted; effects were computed using single proportion analysis with double arcsine transformation.

The final analysis comprised 285 studies. The comorbidity of schizophrenia diagnoses in bipolar patients was low (8%). However, more broadly defined mood incongruent psychosis was quite prevalent (47%). Similarly, psychotic symptoms were common in bipolar patients, specifically those with a type I diagnosis or manic episode; delusions were more common than hallucinations and thought disorders.

Significant overlap in phenomenology and psychopathology was observed between bipolar disorder and schizophrenia in this review. Future research should focus on comparing patients with similar symptoms and exploring the shared processes that contribute to these symptoms.