The purpose of this research is to examine the effect of cannabidiol (CBD), a cannabinoid compound found in marijuana, on responses to emotional stimuli. Both preclinical and clinical studies indicate that CBD may act to reduce anxiety without excessive sedative side-effects. Thus the investigators hypothesize that CBD may reduce responses specifically to negative emotional and social stimuli, including pictures and emotional faces, without altering responses to positive stimuli. To examine this, the investigators will administer placebo, 300mg, 600mg, and 900mg CBD to healthy normal adults in a double-blind within-subjects study. The investigators will measure subjective and subtle physical responses to positive and negative stimuli using measures that have been characterized with classic anxiety-reducing drugs and drugs of abuse. Further, the investigators will examine whether CBD-induced changes in these measures of emotional response relate to changes in actual behavior in a controlled social interaction. These results will allow the investigators to examine the potential usefulness of CBD as an anxiety-reducing drug, and suggest mechanisms by which CBD may reduce anxiety.

Inclusion Criteria:

• 18-35 years of age.
• 38 healthy volunteers (19 male, 19 female; age range 18-35 years)
• All participants recruited without regard to race, religion or ethnicity through posters, advertisements and word-of-mouth referrals.
• Candidates screened in accordance with our general screening protocol, approved by the IRB under Protocol #13681B, which includes a physical, EKG, psychiatric screening interview and detailed drug use history questionnaire.

Exclusion Criteria:

• Individuals with a medical condition contraindicating study participation, as determined by the study site physician.
• Individuals regularly using any medications aside from hormonal contraception in women.
• Individuals with a current (active in the past year) DSM-IV Axis I mood, anxiety, eating, or substance dependence disorder or a lifetime history of a psychotic disorder or mania.
• Women who are pregnant, nursing, or planning to become pregnant in the next 3 months
• Participants reporting a known or suspected allergy to cannabinoids.
• The self-report questionnaires the investigators use require fluency in English, and have not been translated and validated in other languages, thus individuals with less than a high-school education or those not fluent in English were excluded, as lack of English familiarity at a high school level may compromise our ability to interpret their self-reports.
• Individuals with a BMI below 19 or above 30, as this would change dosing requirements.
• Individuals who report using marijuana >100 times in their lifetime, to reduce variation in possible developed tolerance to CBD.

.Through study completion, an average of 5 weeks.