The effects of tetrahydrocannabinol on dopamine release

INTERVENTION: Healthy subjects will inhale placebo or 8 mg of THC, the main psychoactive ingredient of cannabis, by means of a vaporizer. CONDITION: No condition, healthy person ; Nervous System Diseases PRIMARY OUTCOME: After inhalation of THC, dopamine release will be investigated using the 11C‐raclopride displacement paradigm. Increase in striatal synaptic dopamine will be measured by the decline in D2 receptor availability to the binding of 11C‐raclopride. This binding will be demonstrated using positron emission tomography (PET). SECONDARY OUTCOME: Behavioral parameters (brief psychiatric rating scale [BPRS] and two visual analogue scale [VAS] questionnaires) and the concentration of plasma THC and its main metabolites will be obtained as well. Vital signs (blood pressure and heart rate) will be measured regularly. INCLUSION CRITERIA: 1. Aged between 18 and 45 years 2. History of mild cannabis use for at least one year (<1 per week and >=4 per year 3. History of no further illicit drug use 4. History of no psychotic experiences after cannabis use 5. Written informed consent of the subject