Use of Some Prescription Drugs Linked to Violent Behavior

Hand picks out prescription medication from cabinetPainkillers and benzodiazepines are among the world’s most popular drugs. Every year, doctors in the United States write more than 100 million benzodiazepine prescriptions and more than 250 million painkiller prescriptions. Though these drugs can offer immense relief from physical and psychological pain, they also come with some risks. According to a new study published in World Psychiatry, one of those risks might be an increased likelihood of committing murder.

Can Painkillers and Benzodiazepines Lead to Homicide?

In the aftermath of a massacre, media reports often highlight the mental health status of the killer. Because mental health issues are not statistically correlated with an increased risk of violence, and because those with mental health issues are more likely to be victims than victimizers, some advocates have looked for other explanations. Some argue that violent behavior is not the product of mental health issues, but instead of the drugs used to treat the condition.

To explore how psychiatric drugs might affect mental health, Swedish and Finnish researchers looked at the use of psychiatric drugs among 959 convicted murderers. Because a person’s environment, the drugs they take, and their mental health status may all affect their behavior, researchers controlled for the potential effects of other drugs and intoxicants, as well as the underlying mental health issues of each participant.

Researchers did not find a significant association between the use of antipsychotic drugs and homicide. The use of antidepressants, though, slightly increased the murder rate, producing a 31% increased risk of committing a homicide. Study subjects who had been prescribed benzodiazepines for insomnia or anxiety, and those who used painkillers were significantly more likely to commit murder. Benzodiazepines increased the risk of murder by 45%, compared to a 92% increased risk among opiate painkiller users. Among those who used anti-inflammatory painkillers, the risk increased by 206%.

The risk was elevated even further among young people. Among those under the age of 26, benzodiazepines increased the risk of homicide by 95%, while opiates increased the risk by 223%. The study’s authors point to previous research suggesting that painkillers may interfere with emotional processing. Likewise, benzodiazepines can weaken impulse control. It’s unlikely, then, that these drugs cause murders by themselves. Instead, they may weaken the resistance toward violence among people who already have strong feelings of aggression or anger.


  1. Cascade, E., & Kalali, A., MD. (2008). Use of benzodiazepines in the treatment of anxiety. Psychiatry, 5(9), 21-22.
  2. Opioid painkiller prescribing. (2014, July 01). Retrieved from
  3. Use of certain painkillers linked with increased risk of homicide. (2015, June 1). Retrieved from

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  • Leave a Comment
  • chelle

    June 2nd, 2015 at 10:42 AM

    is it just me or are these numbers just insane?!

  • Grayson

    June 2nd, 2015 at 6:55 PM

    It is hard for me to understand how something that can do so much good can also cause a person to turn into someone completely different.

  • Ben

    June 4th, 2015 at 4:34 PM

    So here is the ten million dollar question-
    if these are drugs that can be so harmful then why in the world are they allowed to be continually prescribed and sold in this country? I would have thought that is there was truly this much of a problem then the FDA would have yanked them the way they did those diet pills several years ago. But who is profiting from them staying around? I think that we all know that the pharmaceutical companies are a pretty powerful lobby.

  • Tammi

    June 8th, 2015 at 4:16 PM

    It may not necessarily be a foregone conclusion that these drugs will cause this kind of behavior in everyone. It could be that there is something in a person’s DNA that would cause him to react this way, so it may not necessarily be the drug but how the body is made up and how it then reacts with that substance on a chemical level. There are so many things that one has to take into consideration when you are looking at an issue such as this. It doesn’t mean that there is only one easy answer. There could be multiple scenarios that could cause this kind of behavior to emerge.

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