The bill would allow those 21 and older to possess for personal use small amounts of psilocybin, the hallucinogenic component of so-called magic mushrooms. It also covers psilocyn, dimethyltryptamine (DMT), ibogaine, mescaline excluding peyote, lysergic acid diethylamide (LSD) and 3,4-methylenedioxymethamphetamine (MDMA, often called ecstasy).

But the California District Attorneys Association was among groups that remained opposed, arguing that “hallucinations can be dangerous to users and bystanders alike” and that LSD has been linked to homicides.

Wiener said the decriminalization would be “part of the larger movement to end the racist War on Drugs,” and that research shows the drugs can help treat mental health and substance use disorders.

The University of Wisconsin–Madison said this week it is launching a research center to coordinate ongoing studies and education in psychedelic compounds. It cited growing evidence of their utility in treating substance abuse and psychiatric disorders, such as major depression and post-traumatic stress disorder.