Every couple years, proponents for legalizing MDMA -- the main ingredient in the recreational drug ecstasy -- pop up in the media.

During 2012, the chief medical officer for the Canadian province of British Columbia told reporters that MDMA is safe in pure form, and advocated full legalization.

Just last year, an emergency medicine specialist and clinical toxicologist in New Zealand also called for MDMA legalization, claiming that the drug “was not associated with violence.”

On the contrary, there is substantial evidence in the peer-reviewed literature that MDMA is associated with aggressive behavior and violence.

Writing in the journal Violence and Victims, researchers from Georgia State University and Emory University reported the following findings:

[C]linical studies have established a link between aggression and ecstasy (3,4-methylenedioxymeth-amphetamine [MDMA])... Studies that compare the levels of aggressive behavior between ecstasy users and nonusers find that those who have used ecstasy report significantly greater levels of aggression and hostility. This finding holds even for those who have abstained from ecstasy use for an extended period of time... virtually every recent study sampling users from the current ecstasy drug culture clearly establishes a positive relationship between ecstasy use and aggression... Our results clearly suggest that those with a higher prevalence of lifetime ecstasy use exhibit higher levels of aggressive and violent behavior. The more ecstasy one has used in his or her lifetime, the greater variety of violent acts he or she commits. The odds of committing more types of violent acts in the past year increases almost linearly with the number of ecstasy pills ever used.

Another study discusses “a case of acute paranoid psychosis in a patient who took MDMA (Ecstasy), became violent and was prosecuted by law. After the repeated intake of MDMA, the second psychotic episode occurred.” Further research out of Germany found that “even typical recreational doses of ecstasy are sufficient to cause neurotoxicity in humans.”

From an article in the Journal of Substance Abuse, a group of Italian researchers came to the following conclusions about MDMA:

Our findings evidence increased levels of outward-directed aggressiveness in Ecstasy users: Aggressive responses to provocation were higher in the subjects exposed to MDMA than those of healthy subjects who have never used Ecstasy, during the entire laboratory procedure. In comparison with our data obtained with the same experimental paradigm in methadone patients, the subjects included in the present study who have taken Ecstasy showed during the first session even more aggressiveness than heroin addicts. These results are in agreement with the reports demonstrating more impulsiveness and hostility in heavy Ecstasy users and with our previous psychometric measures that evidenced high levels of aggressiveness three weeks after MDMA discontinuation.

Finally, a study published last year by researchers from Saint Louis University, the University of Texas, Iowa State University, and the University of Michigan -- which conducted the largest ever investigation on MDMA and crime -- yielded the following insights into the risks from this drug:

This study [assessed] the association between MDMA use and violent and non-violent antisocial behavior while controlling for sociodemographic variables, lifetime psychiatric, alcohol and drug use disorders, and family history of antisocial behavior... MDMA users were still at significantly greater odds of engaging in violent and nonviolent crime than non-MDMA users... These findings support prior research that indicated that MDMA is associated with aggression... Although MDMA use is substantially less than that of alcohol and other substances found to be associated with violence, it nevertheless is a contributor to the drugs-violence public health nexus.

Consequently, we have plenty of evidence showing linkages between MDMA use and violent behavior -- and this data needs to stay front-and-center in the public discussion over possible legalization of the drug.