A new study published in Psychiatry Research provides evidence that antidepressant medications are not strongly associated with mass shootings in the United States. Using one of the largest databases of mass murders to date, researchers at Columbia University analyzed over 800 incidents involving firearms between 1990 and 2023. Their findings suggest that only a small percentage of mass shooters had a history of taking antidepressants or other psychiatric medications, and there was no clear link between medication use and suicide attempts during the attacks.
Concerns about the possible role of antidepressant medications in acts of mass violence have persisted for decades. These worries are fueled in part by warnings issued by regulatory agencies about potential increases in suicidal thinking and behavior in some people who take these medications. Media coverage has also sometimes pointed to psychiatric drugs as potential factors in mass shootings, raising public unease.
At the same time, research has consistently shown that mass shooters often have mental health struggles, including a high rate of suicidality. Previous studies have explored the mental health histories of mass murderers, but few have closely examined whether psychiatric medications might be involved in these events.
Given this backdrop, the research team wanted to take a closer look using the Columbia Mass Murder Database, a resource they developed to study the relationships between mental illness, medication, and violence. Their goal was to provide a more data-driven answer to whether antidepressants or other psychotropic drugs might play a role in firearm-based mass killings.
“My area of interest is schizophrenia, with a focus on violence in schizophrenia. I wanted to determine as definitively as possible, for myself, whether there is a relationship between mass shootings and mental illness. This motivated my colleagues and I to create the Columbia Mass Murder Database and pursue this line of work,” said study author Ragy R. Girgis, a professor of clinical psychiatry at Columbia University.
The researchers focused on incidents in the United States that occurred between 1990 and 2023, selecting only those events in which three or more people were killed by gunfire, not including the perpetrator. Events related to organized crime, terrorism, or war were excluded. The study relied on publicly available sources including media reports, court records, police statements, and existing databases. These materials were reviewed for any information about whether a perpetrator had ever been prescribed or taken psychiatric medications.
Out of 852 mass shootings included in the study, only 34 perpetrators (about 4 percent) were found to have a lifetime history of antidepressant use. Five individuals (0.6 percent) had taken antipsychotic medications, and another 37 (4.3 percent) had been treated with other or unspecified psychiatric drugs. In total, 56 shooters (6.6 percent) had any known history of psychotropic medication use at any point in their lives.
The researchers also looked at whether there was any connection between medication use and suicide attempts during these events. A total of 279 perpetrators attempted to take their own lives during the attack. Among this group, 15 individuals (5.4 percent) had used antidepressants, compared to 19 individuals (3.3 percent) who did not attempt suicide. This difference was not statistically significant.
A similar pattern appeared when the researchers considered all psychiatric medications, not just antidepressants. Suicide attempts were slightly more common among those with any history of medication use, but again, the difference was not meaningful from a statistical standpoint.
Importantly, the data suggested that in more than half of the cases involving psychiatric medications, the perpetrator was not actively taking the medication at the time of the shooting. In nearly a third of the cases, the shooter was believed to be taking the medication during the event, but the researchers found no evidence that the medication had any direct role in the attack. In the remaining cases, it was unclear whether the person was currently using the drugs.
The study also placed its findings in context by comparing the rates of antidepressant use among mass shooters to rates in the general population. According to previous population-based data, antidepressant use in the United States is much higher than the rate observed among perpetrators in this study. This suggests that if psychiatric medications were directly causing mass shootings, the proportion of shooters using them would likely be much higher than what was found.
“The vast majority of mass shootings have nothing to do with mental illness,” Girgis told PsyPost. “Psychiatric medications, and SSRIs in particular, do not cause mass shootings. The primary modifiable population level risk factor for mass shootings is firearm availability.”
But as with all research, there are limitations. First, all data were collected from publicly available sources, such as news articles and online records. This approach may miss cases where medication use was not reported or was kept confidential. The study also could not always determine whether medications were being taken as prescribed at the time of the attack, or whether the person had recently stopped taking them.
Another limitation relates to the difficulty of distinguishing between suicidal thoughts that are a side effect of medication and those that are part of the mental health condition the medication was intended to treat. This distinction is important because many people begin treatment due to existing suicidality, not because the medication caused it.
In the meantime, the authors suggest that prevention efforts should shift focus away from medication use and toward better identification and treatment of individuals with untreated mental illness. They note that only about five percent of mass shootings appear to be directly related to untreated mental health conditions. As such, they argue that the broader causes of mass shootings, including access to firearms and the cultural portrayal of gun violence, deserve more attention in public discussions and policy-making.
“We have published most of the major findings from our work,” Girgis said. “We plan to publish additional findings on legal outcomes after mass murder (for those perpetrators who do not take their life at the time of the event), relationships between adverse childhood experiences and mass murder, and relationships between a prior history of domestic violence among perpetrators and later familicide mass murder, among others.”
“In addition to the huge role that weak firearm laws play in mass shootings, the romanticization of gun violence by the entertainment industry (movies, television, video games, music) is a key factor in the rise of gun violence in America.”
The study, “Antidepressant use and suicide among U.S.-based mass murderers who use firearms: 1990-2023,” was authored by Ragy R. Girgis, Hannah Hesson, and Gary Brucato.
