Benzodiazepine use and aggressive behaviour : a systematic review

Context: The relationship between benzodiazepine consumption and subsequent increases in aggressive behaviour in humans is not well understood. Objectives: The current study aimed to identify, via a systematic review, whether there is an association between benzodiazepine consumption and aggressive responding in adults. Method: A systematic review was conducted and reported in line with the PRISMA statement. English articles within MEDLINE, PsycARTICLES, PsycINFO, Academic Search Complete, and Psychology and Behavioural Sciences Collection databases were searched. Additional studies were identified by searching reference lists of reviewed articles. Only articles that explicitly investigated the relationship between benzodiazepine consumption and subsequent aggressive behaviour, or a lack thereof, in human adults were included. Results: Forty-six studies met the inclusion criteria. It was not possible to conduct a meta-analysis due to the heterogeneity of study design and benzodiazepine type and dose. An association between benzodiazepine use and subsequent aggressive behaviour was found in the majority of the more rigorous studies, although there is a paucity of high-quality research with clinical or forensic populations. Diazepam and alprazolam have received the most attention. Dose-related findings are inconsistent: therapeutic doses may be more likely to be associated with aggressive responding when administered as a once-off, whereas higher doses may be more risky following repeated administration. Trait levels of anxiety and hostility may indicate a vulnerability to the experience of benzodiazepine-related aggression. Conclusions: There appears to be a moderate association between some benzodiazepines and subsequent aggressive behaviour in humans. The circumstances under which aggressive responding may be more likely to follow benzodiazepine use remain unclear, although some evidence suggests dose and/or personality factors may influence this effect.