Abstract
BACKGROUND: Schizophrenia is a prevalent disease, affecting 1% of the global population. Its negative symptoms are a source of significant morbidity and socioeconomic disability and display high treatment refractoriness. Deep brain stimulation (DBS) is currently being investigated as a possible treatment for various treatment-resistant psychiatric disorders, including treatment-resistant schizophrenia (TRS). In this systematic review, we aim to assess whether DBS is efficacious in treating the negative symptoms of TRS. METHODS: We developed a search string using DBS and TRS as two concepts to search for DBS studies in adult TRS patients on six databases: PubMed, Cochrane Library, Scopus, Web of Science, Cinahl Ultimate, and Embase. Duplicates were resolved. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used to select relevant articles. Data regarding participant age, gender, stimulation site, pre- and lowest post-DBS positive and negative syndrome scale (PANSS) negative scores, and time taken to achieve that lowest score was extracted. Averages were found for all variables and a paired sample t-test was run to check whether the difference between pre- and lowest post-DBS PANSS negative score was statistically significant. RESULTS: Nineteen patients with TRS from five studies were included in our analysis having an average age of 38.74 years and with 10 participants (52.6%) being female. The average pre-DBS negative score was 24.311 and the mean lowest post-DBS score was 16.95. The time taken post-DBS to achieve the best improvement ranged from 6 to 36 months, with a mean duration of 23.26 months. The difference between pre- and post-DBS scores was found to be statistically significant (P < 0.001). CONCLUSION: Preliminary evidence suggests DBS might have efficacy in treating negative schizophrenia symptoms. Higher quality studies with larger sample sizes are needed to further back this claim. Researchers must look to maintain methodological consistency in their studies to allow easier comparability between them.