In a first study of its own kind, Finnish researchers have linked the use of painkillers and antidepressants to an increased risk of committing a homicide. According to the researchers, painkillers that affect the central nervous system may lead people to commit murders.

“I think that these chemical substances affect the impulse control of the person,” said lead researcher and professor Dr. Jari Tiihonen, in a statement. “The only surprising result was that painkillers also increase the risk.”

Various research in the past has tried to study the effect of antidepressants in the past. However, this time, Tiihonen and his team studied the effect of painkillers and other psychotropic medications.

The research team analyzed the use of prescription drugs among people who were later convicted of homicide in Finland between the years 2003 and 2011. The team retrieved the data about the prescription drugs and the criminal record of the people from the national database.

Upon comparing the record of each criminal against 10 other controls belonging to the same gender, municipality and age, the researchers found that it was benzodiazepines and painkillers indeed that had put people at a higher risk of committing homicide.

“On the basis of our results, benzodiazepines and painkillers, but not antidepressants, are linked to a significantly higher risk,” claimed Tiihonen.

The study results found that antidepressants increase the tendency to commit homicide by 31 percent, while benzodiazepines elevate the risk by 45 percent. Shockingly, the use of painkillers was found to have increased the homicidal tendency by 92 percent and the use of anti-inflammatory painkillers by 206 percent.

Finland maintains its own detailed drug registry within the country, which provided an an excellent source of actual data for the study to the researchers. The research team hopes the study data and results to be replicated in some other country as well.

However, there are certain limitations. Not all countries maintain a nationwide database or drug registry, and some countries have a high homicide rate due to organized crime.