Protocol and rationale: A 24-week double-blind, randomised, placebo controlled trial of the efficacy of adjunctive Garcinia mangostana Linn. (mangosteen) pericarp for schizophrenia.
Alyna Turner 1, 2, 3*, John J McGrath 4, 5, 6, Olivia M Dean 1, 3, 7, Seetal Dodd 1, 3, 8, Andrea Baker 4, Susan M Cotton 8, 9, James G Scott 4, 10, 11, Bianca E Kavanagh 1, Melanie M Ashton 1, 6, 12, Adam J Walker 1, Ellie Brown 1, 3, Michael Berk 1, 3, 7
1Deakin University, IMPACT Strategic Research Centre, School of Medicine, Barwon Health, P.O. Box 281, Geelong, 3220, Australia, 2School of Medicine and Public Health, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, 2308, 3University of Melbourne, Department of Psychiatry, Level 1 North, Main Block, Royal Melbourne Hospital, Parkville, 3052, Australia , 4Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, Australia, 5Queensland Brain Institute, University of Queensland, St Lucia, Australia, 6National Centre for Register-based Research, Aarhus BSS, Aarhus University, 8210 Aarhus V Denmark, 7Florey Institute for Neuroscience and Mental Health, University of Melbourne, Kenneth Myer Building, 30 Royal Parade, 3052, Parkville, Australia., 8Centre for Youth Mental Health, The University of Melbourne, 35 Poplar Rd, Parkville, 3052, Australia, 9Orygen, The National Centre of Excellence in Youth Mental Health, 35 Poplar Rd, Parkville, 3052, Australia., 10Metro North Mental Health Service, Herston, Queensland, Australia, 11Faculty of Medicine, The University of Queensland, Herston, Queensland Australia, 12Department of Psychiatry, University of Melbourne, Professorial Unit, The Melbourne Clinic, 130 Church St Richmond Australia 3121
Received: September 7, 2018; Revised: October 31, 2018; Accepted: November 1, 2018; Published online: November 1, 2018.
© The Korean College of Neuropsychopharmacology. All rights reserved.

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 randomised placebo-controlled trial evaluating the efficacy of adjunctive mangosteen pericarp (1000 mg/day), compared to placebo, in the treatment of schizophrenia.
We aim to recruit 150 participants across two sites (Geelong and Brisbane). Participants diagnosed with schizophrenia or schizoaffective disorder will be randomised 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 (PANSS) (total score) over the course of 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 will be conducted at week 28 to explore post-discontinuations effects.
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.
Keywords: Mangosteen, mangostana garcinia Linn., schizophrenia, schizoaffective disorder, treatment clinical trial, oxidative stress