OBJECTIVE: Garcinia mangostana Linn., commonly known as mangosteen, is a tropical fruit with a thick pericarp rind containing bioactive compounds that may be beneficial as an adjunctive treatment for schizophrenia. The biological underpinnings of schizophrenia are believed to involve altered neurotransmission, inflammation, redox systems, mitochondrial dysfunction, and neurogenesis. Mangosteen pericarp contains xanthones which may target these biological pathways and improve symptoms; this is supported by preclinical evidence. Here we outline the protocol for a double-blind randomized placebo-controlled trial evaluating the efficacy of adjunctive mangosteen pericarp (1,000 mg/day), compared to placebo, in the treatment of schizophrenia. METHODS: We aim to recruit 150 participants across two sites (Geelong and Brisbane). Participants diagnosed with schizophrenia or schizoaffective disorder will be randomized to receive 24 weeks of either adjunctive 1,000 mg/day of mangosteen pericarp or matched placebo, in addition to their usual treatment. The primary outcome measure is mean change in the Positive and Negative Symptom Scale (total score) over the 24 weeks. Secondary outcomes include positive and negative symptoms, general psychopathology, clinical global severity and improvement, depressive symptoms, life satisfaction, functioning, participants reported overall improvement, substance use, cognition, safety and biological data. A 4-week post treatment interview at week 28 will explore post-discontinuations effects. RESULTS: Ethical and governance approvals were gained and the trial commenced. CONCLUSION: A positive finding in this study has the potential to provide a new adjunctive treatment option for people with schizophrenia and schizoaffective disorder. It may also lead to a greater understanding of the pathophysiology of the disorder.
Cognition ; Depression ; Fruit ; Garcinia mangostana ; Garcinia ; Inflammation ; Neurogenesis ; Outcome Assessment (Health Care) ; Oxidation-Reduction ; Oxidative Stress ; Psychopathology ; Psychotic Disorders ; Schizophrenia ; Synaptic Transmission ; Xanthones

Objective: There is often a shortfall in recovery following treatment for an episode of bipolar disorder (BD). Exploration of participant’s experience provides vital information to enhance statistical outcomes for novel therapy trials. This study used mixed-methods to explore participants’ experience of a trial testing N -acetyl cysteine (NAC) and mitochondrially active nutraceuticals for BD depression. Methods: Case report forms from a randomised controlled trial (RCT) of BD depression (n = 148) were analysed using a pragmatic adaption of grounded theory and thematic analysis. Results: Thematic analysis of 148 study participants indicated numerous changes in participant experience over time. For example, perceived environmental stressors reported by participants decreased over the trial in both treatment groups. Quantitative analysis of the themes revealed more positive theme reports in the combination treatment arm compared to the placebo arm and there were more negative themes identified in the placebo arm, compared to the NAC arm. Conclusion This approach revealed additional results not elucidated in the primary quantitative analysis. This emphasises the value of mixed-methods research in capturing participants’ experiences in RCTs and detecting possible latent benefits and risks. Such methods can detect latent target signals in novel therapy trials conducted in BD and generate novel hypotheses.