Effects of N-acetylcysteine on substance use in bipolar disorder: A randomised placebo-controlled clinical trial.
OBJECTIVE
To evaluate the effect of N-acetylcysteine (NAC) on substance use in a double-blind, placebo-controlled trial of NAC in bipolar disorder. It is hypothesised that NAC will be superior to placebo for reducing scores on the Clinical Global Impressions scale for Substance Use (CGI-SU).


METHODS
Participants were randomised to a 6-months of treatment with 2 g/day NAC (n = 38) or placebo (n = 37). Substance use was assessed at baseline using a Habits instrument. Change in substance use was assessed at regular study visits using the CGI-SU.


RESULTS
Among the 75 participants 78.7% drank alcohol (any frequency), 45.3% smoked tobacco and 92% consumed caffeine. Other substances were used by fewer than six participants. Caffeine use was significantly lower for NAC-treated participants compared to placebo at week 2 of treatment but not at other study visits.


CONCLUSIONS
NAC appeared to have little effect on the participants who were using substances. A larger study on a substance-using population will be necessary to determine if NAC may be a useful treatment for substance use.
1The University of Melbourne, Department of Clinical and Biomedical Sciences: Barwon Health, Geelong, Australia.
Michelle
M
Bernardo
1The University of Melbourne, Department of Clinical and Biomedical Sciences: Barwon Health, Geelong, Australia.
Seetal
S
Dodd
4Laboratório de Psiquiatria Molecular, Centro de Pesquisas, Hospital de Clínicas de Porto Alegre, Brazil.
Clarissa S
CS
Gama
3Mental Health Research Institute, Parkville, Australia.
David L
DL
Copolov
1The University of Melbourne, Department of Clinical and Biomedical Sciences: Barwon Health, Geelong, Australia.
Olivia
O
Dean
1The University of Melbourne, Department of Clinical and Biomedical Sciences: Barwon Health, Geelong, Australia.
Kristy
K
Kohlmann
3Mental Health Research Institute, Parkville, Australia.
Susan
S
Jeavons
3Mental Health Research Institute, Parkville, Australia.
Ian
I
Schapkaitz
3Mental Health Research Institute, Parkville, Australia.
Murray
M
Anderson-Hunt
3Mental Health Research Institute, Parkville, Australia.
Ashley I
AI
Bush
1The University of Melbourne, Department of Clinical and Biomedical Sciences: Barwon Health, Geelong, Australia.
Michael
M
Berk