Some Painkillers, Sedatives May Increase Urge To Kill: Study

Side effects of prescription drugs are common and vary widely, but a new study suggests that certain painkillers, antidepressants and other prescription sedatives may be linked to an increased risk of committing murder. 

In a new study, the first of its kind in the world, researchers found that people who took antidepressants, painkillers, anxiety and insomnia medications were more likely to commit homicide. The findings were published in the June issue of the journal World Psychiatry, but were detailed in a press release issued June 1, by the University of Eastern Finland.

The Finnish-Swedish study analyzed pre-crime use of prescription drugs among nearly 1,000 people convicted of homicide in Finland between 2001 and 2011. Researchers used both the Finnish Homicide Database of the Institute of Criminology and Legal Policy and the Finnish Prescription Register of the Social Insurance Institution of Finland for data.

Researchers found the use of opiate painkillers, such Vicodin and OxyContin, were associated with a 92% increased risk of committing murder. Taking anti-inflammatory painkillers was associated with an increased risk of committing homicide by 206%.

The study also found the use of antidepressants, such as Zoloft and Lexapro, was associated with a 31% elevated risk of committing murder. Commonly taken benzodiazepines, like Valium and Xanax used to treat insomnia and anxiety, were associated with a 45% elevated risk of committing murder.

Jari Tihonen, lead author of the study, and a team of researchers said unlike the other medications, the use of antipsychotics was not associated with an increased risk of committing murder.

The greatest risk was among people under the age of 26, who faced a 223% increased risk of committing murder after taking opiate painkillers, including Vicodin, and a 95% increased risk after taking benzodiazepines, like Xanax.

“Benzodiazepines can weaken impulse control, and earlier research has found that painkillers affect emotional processing,” said Tiihonen. “Caution in prescribing benzodiazepines and strong painkillers to people with a history of substance abuse is advisable.”

Researchers say the use of certain prescription drugs can affect the central nervous system. This is associated with increased risk of committing murder and may raise concerns, considering the large number of people in the U.S. who are taking medications among these groups in question.

The team also considered the reason the person was taking the prescription drugs, the effects the drugs had on the person and other drugs or intoxicants the person was using. Use of intoxicants were present in the majority of homicides. However, the differences between the risk in drug groups could not be explained by simultaneous intoxicant use.

“It has been repeatedly claimed that it was the antidepressants used by the persons who committed these massacres that triggered their violent behavior,” said Tiihonen speaking of recent mass murder events. “It is possible that the massive publicity around the subject has already affected drug prescription practices.”

The study was conducted in collaboration between the Karolinska Institute in Sweden, the University of Eastern Finland.