Roland Griffiths, Ph.D., is Professor in the Departments of Psychiatry and Neurosciences at the Johns Hopkins University School of Medicine. His principal research focus in both clinical and preclinical laboratories has been on the behavioral and subjective effects of mood-altering drugs. His research has been largely supported by grants from the National Institute on Health and he is author of over 400 journal articles and book chapters, and has trained more than 50 postdoctoral research fellows. He has been a consultant to the National Institutes of Health, to numerous pharmaceutical companies in the development of new psychotropic drugs, and as a member of the Expert Advisory Panel on Drug Dependence for the World Health Organization. He has conducted extensive research with sedative-hypnotics, caffeine, and novel mood-altering drugs. In 1999 he initiated a research program investigating the effects of the classic psychedelic psilocybin that includes studies in healthy volunteers, in beginning and long-term meditators, and in religious leaders. Therapeutic studies with psilocybin include treatment of psychological distress in cancer patients, treatment of cigarette smoking cessation, and psilocybin treatment of major depression. Other studies have examined the effects of salvinorin A, dextromethorphan, and ketamine which produce altered states of consciousness having some similarities to psilocybin. Drug interaction studies and brain imaging studies (fMRI and PET) are examining pharmacological and neural mechanisms of action. The Hopkins laboratory has also conducted a series of internet survey studies characterizing various psychedelic experiences including those associated with acute and enduring adverse effects, mystical-type effects, entity and God-encounter experiences, and alleged positive changes in mental health, including decreases in depression and anxiety, decreases in substance abuse, and reductions in death anxiety.