Why some drugs are linked with increased suicidal ideation remains a major unsolved mystery. One 2009 study identified 800+ drugs spanning categories from analgesics to flu treatments to anti-cancer meds that were linked to more suicidal thoughts and suicide attempts. But the mechanism(s) by which a given drug might cause a user to contemplate suicide are almost completely unknown. This, and the equally unexplained rise in placebo responses in clinical trials, should prompt more investigations into how pharmacological molecules trigger biopsychosocial effects.