In the 1950s through the early '70s, research began to show that psychedelics like LSD and psilocybin, the active ingredient in magic mushrooms, could be quite effective at treating mental health disorders like addiction. Then ... the so-called war on drugs" began. For nearly a generation, science on these substances shut down. But that's changing. In the past 20 years or so, a small amount of research has once again begun to focus on these chemicals, showing that they have promise for treating a range of conditions, from addiction to depression and anxiety, says Evan Wood, a psychiatric researcher at the University of British Columbia. In 2006, researchers at the University of Arizona published a study showing obsessive-compulsive patients who ingested psilocybin had immediate and lasting reductions in problematic symptoms. The same year, Johns Hopkins University physician and researcher Roland Griffiths showed that in healthy volunteers, psilocybin produced lasting benefits like improved mood and peacefulness six months after ingestion. Similar work has shown psilocybin can help treat anxiety associated with cancer, at UCLA and New York University. And a study in late 2014 found that LSD permanently reduced anxiety in a small number of patients. Wood says he's most excited about research into using psychedelics to treat addiction. He published a review on September 8 in the Canadian Medical Association Journal covering recent work in this field.