Among the last 20 confirmed mass murder incidents in the United States, approximately 7 perpetrators were confirmed to have been taking psychotropic medications at the time of their attacks or shortly beforehand, while roughly 15–16 had a documented history of mental health treatment, including therapy, psychiatric care, or prior prescriptions, even if they were not actively medicated at the time. Shooters with confirmed psychotropic medication use include Shane Tamura (NYC, 2025; antidepressants and epilepsy medication), Connor Betts (Dayton, 2019; antidepressants), Steven Kazmierczak (NIU, 2008; Prozac, Xanax, Ambien), James Holmes (Aurora, 2012; psychiatric care for schizoaffective disorder), Noah Esbensen (Copenhagen, 2022; antipsychotics), Seung-Hui Cho (Virginia Tech, 2007; Lexapro), and some reports for Esteban Santiago (Fort Lauderdale, 2017). Shooters with a documented history of mental health treatment, but without confirmed current medication use, include Robin Westman (Minneapolis, 2025), Esteban Santiago, Muhammad Youssef Abdulazeez (Chattanooga, 2015), Nikolas Cruz (Parkland, 2018), Christopher Harper-Mercer (Umpqua, 2015), Aaron Alexis (Washington, D.C., 2013), and Nidal Hasan (Fort Hood, 2009), among others. The remaining shooters either had no confirmed treatment or no publicly reported mental health history. Overall, this shows that while psychotropic medication use was present in some cases (~35%), a far larger proportion of mass shooters (~75%) had documented mental health treatment at some point, demonstrating that mental health issues are a common factor, though neither treatment nor medication reliably predicts mass violence.
