Hallie Helms killed a fellow UW-Platteville student before taking her own life; police noted cannabis metabolite in her system.

Marcus Arduini Monzo killed 14-year-old Daniel Anjorin during a marijuana-induced psychotic episode.

Justin Mohn, 33, shot and decapitated his father, then uploaded a 14-minute YouTube video displaying the severed head, laced with extremist anti-government rhetoric.

Diego Costa Silva, who killed and decapitated his wife under the delusion she was a serpent, was found not guilty by reason of insanity due to cannabis-induced psychosis.

Deric Young allegedly beat a 1‑year‑old to death, later telling investigators, “When I smoke, I want to play,” having smoked marijuana minutes before the attack.

Emma Borowy—habitual high-THC cannabis user with schizophrenia—escaped psychiatric care and killed her 74‑year‑old uncle, Roger Leadbeater, during a supervised leave.

Lukas Mironovas, 15, strangled and stabbed his mother after she confronted him about stealing her marijuana.

Adam Kehl, in a state of cannabis-induced psychosis, stabbed and decapitated his father at a family gathering.

Connor Betts, who killed nine people, had a long addiction history including marijuana, meth, and heroin.

Shooter DeWayne Craddock, who killed 12 people, was seen smoking marijuana by neighbors shortly before the massacre.