# The efficacy of adjunctive Garcinia mangostana Linn. (mangosteen) pericarp extract for bipolar depression: 24-week randomised controlled trial

## TL;DR

A 24-week trial found limited evidence that mangosteen extract, when used alongside standard treatment, may improve mood and social functioning in people with bipolar depression.

## Contribution

This study explores mangosteen pericarp extract as a novel adjunctive therapy for bipolar depression through a large randomized controlled trial.

## Key findings

- Mangosteen extract showed greater improvements in mood symptoms compared to placebo at 24 weeks.
- Improvements in social functioning and bipolar severity were observed in the mangosteen group.
- Effects were reduced at 28 weeks post-discontinuation, suggesting limited long-term efficacy.

## Abstract

Bipolar depression remains difficult to treat, and people often experience ongoing residual symptoms, decreased functioning and impaired quality of life. Adjunctive therapies targeting novel pathways can provide wider treatment options and improve clinical outcomes. Garcinia mangostana Linn. (mangosteen) pericarp has serotonogenic, antioxidant anti-inflammatory and neurogenic properties of relevance to the mechanisms of bipolar depression.

The current 28-week randomised, multisite, double-blind, placebo-controlled trial investigated mangosteen pericarp extract as an adjunct to treatment-as-usual for treatment of bipolar depression.

This trial was prospectively registered on the Australia New Zealand Clinical Trials Registry (no. ACTRN12616000028404). Participants aged 18 years and older with a diagnosis of bipolar I or II and with at least moderate depressive symptoms were eligible for the study. A total of 1016 participants were initially approached or volunteered for the study, of whom 712 did not progress to screening, with an additional 152 screened out. Seventy participants were randomly allocated to mangosteen and 82 to a placebo control. Fifty participants in the mangosteen and 64 participants in the placebo condition completed the treatment period and were analysed.

Results indicated limited support for the primary hypothesis of superior depression symptom reduction following 24 weeks of treatment. Although overall changes in depressive symptoms did not substantially differ between conditions over the course of the trial, we observed significantly greater improvements for the mangosteen condition at 24 weeks, compared with baseline, for mood symptoms, clinical impressions of bipolar severity and social functioning compared with controls. These differences were attenuated at week 28 post-discontinuation assessment.

Adjunctive mangosteen pericarp treatment appeared to have limited efficacy in mood and functional symptoms associated with bipolar disorder, but not with manic symptoms or quality of life, suggesting a novel therapeutic approach that should be verified by replication.