Effects of Psychotropics on the Microbiome in Patients with Depression and Anxiety: Considerations in a Naturalistic Clinical Setting

Yoshihiro Tomizawa, Shunya Kurokawa, Daiki Ishii, Katsuma Miyaho, Chiharu Ishii, Kenji Sanada, Shinji Fukuda, Masaru Mimura, Taishiro Kishimoto

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Background: The antibacterial effects of psychotropics may be part of their pharmacological effects when treating depression. However, limited studies have focused on gut microbiota in relation to prescribed medication. Method: We longitudinally investigated the relationship between patients' prescribed medications and intestinal bacterial diversity in a naturalistic treatment course for patients with major depressive disorders and anxiety disorders. Patients were recruited and their stool was collected at 3 time points during their usual psychiatric treatments. Gut microbiota were analyzed using 16S rRNA gene sequencing. We examined the impact of psychotropics (i.e., antidepressants, anxiolytics, antipsychotics) on their gut microbial diversity and functions. Results: We collected 246 stool samples from 40 patients. Despite no differences in microbial diversity between medication groups at the baseline, over the course of treatment, phylogenic diversity whole-tree diversity decreased in patients on antipsychotics compared with patients without (P =. 027), and beta diversity followed this trend. Based on a fixed-effect model, antipsychotics predicted microbial diversity; the higher doses correlated with less diversity based on the Shannon index and phylogenic diversity whole tree (estimate = -0.00254, SE = 0.000595, P <. 0001; estimate = -0.02644, SE = 0.00833, P =. 002, respectively). Conclusion: Antipsychotics may play a role in decreasing the alpha diversity of the gut microbiome among patients with depression and anxiety, and our results indicate a relationship with medication dosage. Future studies are warranted and should consider patients' types and doses of antipsychotics in order to further elucidate the mechanisms of gut-brain interactions in psychiatric disorders.

Original languageEnglish
Pages (from-to)97-107
Number of pages11
JournalInternational Journal of Neuropsychopharmacology
Issue number2
Publication statusPublished - 2021 Feb 1


  • anxiety
  • depression
  • microbial diversity
  • microbiome
  • psychotropics

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health
  • Pharmacology (medical)


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