Do Antidepressants Increase Violent Behavior?

(Image credit: Dreamstime)

Antidepressants are supposed to make people feel happier and more at ease, but a study has linked several prescription antidepressants to an increased risk of violent behavior, including physical assault and homicide.

The December 2010 study from the Institute for Safe Medication Practices found five antidepressants to be among the 10 prescription drugs most disproportionately linked with reports of violent behavior.

The linking of antidepressants with violent behavior is extremely controversial; some mental health professionals argue that such conclusions can be counterproductive. For instance, some scientists fear depressed patients will be discouraged from seeking appropriate medical care by the warning that the Food and Drug Administration requires on the labels of all antidepressant drugs, referring to aggressive behavior.

Others argue that the rate of violent behavior among those taking antidepressants should not come as a surprise, because those people may already have had behavioral issues that made them prone to violence. In fact, their capacity for violence may have been the very reason they started taking antidepressants.

But the study from the Institute for Safe Medication Practices, a nonprofit watchdog group based in Pennsylvania, weighs against the argument about pre-existing tendencies. Acts of violence towards others are a genuine and serious adverse drug event that is associated with a relatively small group of drugs, including 11 antidepressant drugs, the study said.

The study was based on an analysis of 484 adverse events reported to the FDA from 2004 to 2009 that were related to prescription drugs.

The varying results among drugs for smoking cessation and mood stabilization show it is unlikely that the violence events are attributed to existing problems in the patient populations treated, researchers wrote in the study, which was published in the journal PloS One. Of the top 10 drugs disproportionately linked with reports of violent behavior toward others, five were antidepressants.

Prozac (fluoxetine) was most commonly linked to aggression, increasing violent behavior 10.9 times. Paxil (paroxetine), Luvox (fluvoxamine), Effexor (venlafaxine) and Pristiq (desvenlafaxine) were 10.3, 8.4, 8.3 and 7.9 times, respectively, more likely to be linked with violence.

As for why some people on antidepressants become more violent, study co-author Thomas J. Moore told Life's Little Mysteries that the exact cause of these behavioral changes remains unknown and requires further research.

Several previous studies indicated that certain antidepressants also can increase the risk of suicide, but these results are harder to analyze because the rate of increased suicidal tendencies varies depending on the age of the patient with children and teenagers more vulnerable to suicidal behavior when on antidepressants, according to the FDA.

Got a question? Send us an email and we'll look for an expert who can crack it.

Remy Melina was a staff writer for Live Science from 2010 to 2012. She holds a bachelor’s degree in Communication from Hofstra University where she graduated with honors.