Details of the sensor, called psychLight, appear in the journal Compounds related to psychedelic drugs such as LSD and dimethyltryptamine (DMT) show great promise for treating disorders such as depression, post-traumatic stress disorder, and substance use disorder. These drugs are called psychoplastogens because of their ability to rapidly alter brain connections. But drugs that can cause hallucinations require very careful use and monitoring of patients. Currently, the most effective way to test an experimental drug to see if it causes hallucinations is the “head twitch” assay in rodents. “Scientific studies on psychedelic drugs have been conducted since the 1940s but we still don’t have an effective cellular assay for them,” says coauthor David Olson, assistant professor in the chemistry department at the University of California, Davis.