The June issue of Psychopharmacology includes a report on the latest in a series of psilocybin studies by researchers at Johns Hopkins University, this one focusing on the optimal dosage for achieving "mystical-type experiences having persisting positive effects on attitudes, mood, and behavior." Each of the 18 subjects (only one of whom had used psychedelics before) underwent five eight-hour sessions, spaced one month apart, during which they received either a placebo or one of four psilocybin doses: 5, 10, 20, or 30 milligrams per 70 kilograms of body weight. Thirteen of the subjects (72 percent) had "mystical-type experiences" at the two highest doses. The subjects reported "sustained positive changes in attitudes, mood, and behavior, with the ascending dose sequence showing greater positive effects"—effects that were confirmed by "community observers" (friends, relatives, and colleagues) more than a year later.

One subject reported: "I feel that I relate better in my marriage. There is more empathy—a greater understanding of people and understanding their difficulties and less judgment. Less judging of myself, too." Another said: "I have better interaction with close friends and family and with acquaintances and strangers….My alcohol use has diminished dramatically." Fourteen months after the experiment, 94 percent of the subjects called their psilocybin session one of five most meaningful experiences they'd ever had.

The lead researcher, behavioral biologist Roland Griffiths, is interested in exploring the use of psilocybin to relieve anxiety in terminal cancer patients. Other possible applications include addiction, depression, and post-traumatic stress. The psychiatrist Jerome Jaffe, who was Richard Nixon's drug czar, suggests broader uses:

The Hopkins psilocybin studies clearly demonstrate that this route to the mystical is not to be walked alone. But they have also demonstrated significant and lasting benefits. That raises two questions: could psilocybin-occasioned experiences prove therapeutically useful, for example in dealing with the psychological distress experienced by some terminal patients? And should properly-informed citizens, not in distress, be allowed to receive psilocybin for its possible spiritual benefits, as we now allow them to pursue other possibly risky activities such as cosmetic surgery and mountain-climbing?

Time's Maia Szalavitz has more. Previous Reason coverage of psilocybin research here. My 2007 Reason feature story on religious use of psychedelics here.

[Thanks to Michael Sohm for the tip.]