Benzodiazepines and Aggression

On November 19, 2014, the Australian and New Zealand Journal of Psychiatry published Benzodiazepine use and aggressive behaviour: A systematic review, by Bonnie Albrecht et al, from Deakin University, Melbourne, Australia.

Here are the authors’ 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.”

In their opening paragraphs, the authors point out that benzos are commonly prescribed for anxiety, insomnia, agitation, and alcohol withdrawal.  They also write that although sedation and reduced anxiety are the most common effects of these products, “…there have been reports of some users experiencing behavioural disinhibition following consumption, which includes aggressive behaviour.”

They cite references to studies dating back to 1975 in which aggressive responding was reported following administration of these drugs.  “…it is estimated that anywhere between 1% and 20% of benzodiazepine users experience some form of increased anger or express aggression.”  These aggressive incidents occurred at both low and high doses, and by individuals with and without histories of this kind of behavior.

. . . . . . . . . . . . . . . .

Albrecht et al searched the literature for studies that addressed the question of a link between benzo use and aggression.  From 2492 candidate articles they found 46 in which this link was explicitly investigated.  All 46 articles are listed, with a brief description of each study’s parameters and outcome.  For the purposes of their study, Albrecht et al defined aggressive behavior as  “…physical behaviour directed toward another person with the goal of harming or injuring that person, who is motivated to avoid such behaviour.”

In the discussion section of the paper, the authors state:

“Although it was not feasible to conduct a meta-analysis, according to our review of these studies it appears that benzodiazepine use is moderately associated with subsequent aggressive behaviour.”

In the conclusions section, they state:

“Anecdotal evidence indicates that the benzodiazepine–aggression response is an urgent clinical issue with serious clinical and forensic implications. The reviewed literature suggests that although there appears to be a moderate association between some benzodiazepines and subsequent aggressive behaviour in humans, the circumstances under which aggressive behaviour is likely to follow benzodiazepine consumption remain poorly understood.”

The authors point out that this issue warrants further research:

“The evidence base requires high-quality and systematic investigation of the various benzodiazepines and doses.”

Given that these concerns have been finding expression since at least 1975, and given also the seriousness of the matter, it seems to me that a definitive piece of research is long overdue.


The FDA’s information sheet on Valium lists the following under Psychiatric and Paradoxical Reactions:

“stimulation, restlessness, acute hyperexcited states, anxiety, agitation, aggressiveness, irritability, rage…”

Wikipedia provides a list of paradoxical effects of benzodiazepines generally.  The list includes:

“…aggression, violence, impulsivity, irritability and suicidal behavior…”

. . . . . . . . . . . . . . . .

There are no psychiatrists among the authors of the present study.