Assessment of vestibular dysfunctions in schizophrenia and bipolar disorder - A comprehensive systematic review

The vestibular system is closely linked to brain regions such as hippocampus, thalamus, and prefrontal cortex involved in self-perception, spatial orientation, and emotional regulation. Disruptions in these pathways may underlie symptoms such as hallucinations or mood instability, with emerging evidence suggesting a role of vestibular dysfunction in the clinical features and comorbidities of schizophrenia and bipolar disorder.

The aim of this systematic review was to critically examine the available data on vestibular dysfunction in individuals with schizophrenia and BD, explore possible mechanisms, and evaluate the clinical implications, including therapeutic relevance.

Following PRISMA guidelines, we searched PubMed, Scopus, Web of Science, Cochrane Library, and HTA Database (Jan 2000-Apr 2025) for peer-reviewed studies assessing vestibular function in adults with BD and/or schizophrenia using quantitative methods. Study quality was appraised with the Cochrane Risk of Bias Tool and Newcastle-Ottawa Scale. The review is registered on PROSPERO (CRD42024124991).

Of 854 records, five studies (four cross-sectional, one RCT) met inclusion criteria, using posturography and electrovestibulography to assess vestibular function. Both BD and schizophrenia showed vestibular abnormalities: BD exhibited state-dependent changes during mood episodes, while schizophrenia showed illness-related visual dependence. Vestibular dysfunctions were also linked to cognitive deficits and anxiety. Limitations included small samples, medication effects, and heterogeneous methods.

This review highlights preliminary evidence that vestibular dysfunction is an underrecognized feature of schizophrenia and BD. Integrating vestibular assessments may improve diagnosis and guide rehabilitation, while longitudinal studies are needed to clarify causal links and therapeutic potential.