In a first-of-its-kind study appearing in the journal World Psychiatry, use of certain medications that impact the central nervous system are linked to an increased risk of committing a homicide, possibly due to a weakening of impulse control or emotional processing.

This research reviewed the Finnish Homicide Database of the Institute of Criminology and Legal Policy and the Finnish Prescription Register of the Social Insurance Institution of Finland, Kela for pre-crime use of prescription medications among all individuals convicted of a homicide in Finland from 2003–2011. Antidepressant use was associated with a slightly elevated risk of committing a homicide after adjusting for confounders but use of antipsychotics was not. The greatest increase in risk of committing a homicide was with use of opioids and anti-inflammatory pain medications, except for those under the age of 26 (opioids and benzodiazepines had the greatest risk in this age group). The differences between the drug groups could not be explained by simultaneous intoxicant use despite the fact that the use of intoxicants was present in the majority of the homicides.

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The authors theorize that this association could be due to the effects of the medications; benzodiazepines may weaken impulse control and previous research has suggested that pain drugs could affect emotional processing. While this study only found an association and not a causal relationship between these medications and risk of committing a homicide, the authors advise that clinicians use caution when prescribing benzodiazepines, opioids, and other pain medications to patients with a history of substance abuse.

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