Cluster headaches, anxiety and depression can be debilitating for people living with these conditions. Psychedelic drugs have shown benefits as treatments for these conditions in clinical studies, but not for everyone. Now, in ACS Chemical Neuroscience, researchers report that one reason could be common genetic variations in one serotonin receptor. They found that seven variants uniquely and differentially impacted the receptor’s in vitro response to four psychedelic drugs—psilocin, LSD, 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and mescaline.