Adjunctive Taurine in First-Episode Psychosis: A Phase 2, Double-Blind, Randomized, Placebo-Controlled Study.
OBJECTIVE
Taurine is an inhibitory neuromodulatory amino acid in the central nervous system that activates the GABA- and glycine-insensitive chloride channel and inhibits the N-methyl-D-aspartate receptor. It also functions as a neuroprotective agent and has a role in neural development and neurogenesis. The aim of this study was to determine the efficacy of adjunctive taurine in improving symptomatology and cognition among patients with a DSM-IV first-episode psychotic disorder.


METHODS
121 patients with first-episode psychosis, aged 18-25 years, attending early intervention services consented to participate in this randomized, double-blind, placebo-controlled trial conducted from January 2007 to May 2009. Patients taking low-dose antipsychotic medication were randomly assigned to receive once-daily taurine 4 g or placebo for 12 weeks. The coprimary outcomes were change in symptomatology (measured by the Brief Psychiatric Rating Scale [BPRS] total score) and change in cognition (measured by the Measurement and Treatment Research to Improve Cognition in Schizophrenia [MATRICS] Consensus Cognitive Battery composite score) at 12 weeks. Secondary outcomes included tolerability and safety and additional clinical and functioning measures.


RESULTS
86 participants (n = 47 taurine; n = 39 placebo) were included in the final analysis. Taurine significantly improved symptomatology measured by the BPRS total score (95% CI, 1.8-8.5; P = .004) and psychotic subscale (95% CI, 0.1-1.5; P = .026) compared to placebo. Additionally, improvements were observed in the Calgary Depression Scale for Schizophrenia (95% CI, 0.1-3.0; P = .047) and Global Assessment of Functioning (95% CI, 0.3-8.8; P = .04) scores. There was no group difference in composite cognitive score (95% CI, -1.7 to 1.0; P = .582). A significant group difference was found on one safety and tolerability item (psychic item 2, asthenia/lassitude/increased fatigability) of the Udvalg for Kliniske Undersogelser, with the taurine group showing a more favorable outcome (P = .006).


CONCLUSIONS
Adjunctive taurine did not improve cognition, but it appears to improve psychopathology in patients with first-episode psychosis. The use of taurine warrants further investigation in larger randomized studies, particularly early in the course of psychosis.


BACKGROUND
ClinicalTrials.gov identifier: NCT00420823.
Department of Psychiatry, Donegal Mental Health Service, Scally Pl, Letterkenny, County Donegal, Republic of Ireland. colin.odonnell@yahoo.com.|Department of Psychiatry, Donegal Mental Health Service, Letterkenny, County Donegal, Republic of Ireland.
Colin P
CP
O'Donnell
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.|Centre for Youth Mental Health, The University of Melbourne, Australia.
Kelly A
KA
Allott
Early in Life Mental Health Service, Southern Health, Melbourne, Australia.|School of Psychology and Psychiatry, Monash University, Melbourne, Australia.
Brendan P
BP
Murphy
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.|Centre for Youth Mental Health, The University of Melbourne, Australia.
Hok Pan
HP
Yuen
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.|Centre for Youth Mental Health, The University of Melbourne, Australia.
Tina-Marie
TM
Proffitt
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Alicia
A
Papas
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Jennifer
J
Moral
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Tee
T
Pham
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Michaela K
MK
O'Regan
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Christina
C
Phassouliotis
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.
Raelene
R
Simpson
Orygen, The National Centre of Excellence in Youth Mental Health, Parkville, Victoria, Australia.|Centre for Youth Mental Health, The University of Melbourne, Australia.
Patrick D
PD
McGorry
D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D060825:Cognitive Dysfunction / Q000188:drug therapy* / Q000209:etiology; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D061345:Early Medical Intervention; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011618:Psychotic Disorders / Q000150:complications / Q000188:drug therapy*; D013654:Taurine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D055815:Young Adult
D014150:Antipsychotic Agents; D013654:Taurine