Matthew W. Johnson, PhD is Assistant Professor of Psychiatry and Behavioral Sciences at Johns Hopkins University School of Medicine. Dr. Johnson is an expert in addiction and the behavioral and psychological effects of psychoactive drugs in humans. He has published human drug administration research with cocaine, nicotine, caffeine, various sedatives, and hallucinogens including psilocybin, dextromethorphan, and salvinorin A. In 2008, he published recommended safety guidelines for the re-emerging field of human hallucinogen administration research, and in 2011 the first placebo-controlled study of the psychoactive effects of salvinorin A in humans. In published research with psilocybin he has examined mystical-type effects, persisting changes in attitudes and behaviors, personality change, and psilocybin effects on headache. He is currently studying the effects of psilocybin on a meditation program, and psilocybin in the treatment of anxiety and depression among cancer patients. Dr. Johnson is also principal investigator of an ongoing pilot study examining the putative anti-addiction efficacy of psilocybin in the context of tobacco smoking cessation.