Twenty volunteers between 21-50 years old will each participate in 16 total sessions, including sessions for: screening, preparation, experiment/drug, immediate follow-ups, a 1-month follow-up and 1 post completion urine collection. On each of five experimental session participants will orally ingest capsules of either a placebo or varying doses of one of 18 different psychoactive compounds.

Subjective drug effects will be examined with methods previously used by this laboratory for characterizing the effects of psychoactive substances from a variety different classes. Volunteers will swallow capsules containing various doses of drugs, complete tasks during the session, and rate effects of the drug and complete questionnaires at the end of each session as described below.