To the Editor: We read the article by Bunting and colleagues1 with interest, as it attempted to address the important question of whether agitation and aggression are more commonly seen with methamphetamine toxicity. However, we have several concerns about the results presented in this study and the conclusions drawn by the authors.

First, while they have shown that methamphetamine users were more likely to be agitated and aggressive than patients in other “toxicology-related presentations”, this is not surprising. The most common “toxicology-related presentations” to emergency departments are deliberate self-poisonings with drugs like paracetamol, non-steroidal anti-inflammatory drugs, and benzodiazepines,2 and these agents do not cause significant agitation. The control group in the study by Bunting and colleagues should have been patients presenting with toxicity associated with other recreational drugs.

Second, the real issue is whether agitation and aggression are more common with methamphetamine than with other sympathomimetic agents, such as cocaine, amphetamine and methylenedioxy-methamphetamine, as well as ketamine. The authors should therefore have compared patients in methamphetamine-related presentations with those presenting with toxicological symptoms related to this group of drugs, which have also been shown to be associated with significant aggression.3,4

Third, the authors have not stated how they determined whether the presentation was related to methamphetamine or other drugs. It must be assumed that this was on the basis of patients’ self-report. Patients could potentially have been miscategorised without appropriate confirmatory toxicological screening.

Fourth, the authors made no comment on the effect of ethanol co-ingestion and the risk that this can precipitate violence and aggression, which could be a considerable confounding factor. Previous authors have reported that violence and aggression are more commonly associated with ethanol ingestion than with use of other recreational drugs.4

Finally, we are concerned that the conclusion of their abstract is not backed up by the results of their study, as there are no data presented to support their statement that “methamphetamine appeared to be used consistently, rather than as an episodic ‘party drug’”. We therefore urge that clinicians interpret the results of this study with caution.