No documents were ever submitted to the Ethics Committee or the competent authority because it was not possible to establish the planned PET measurements in Germany. Therefore, the study never started.

The study evaluates the gene-environment interaction of the COMT-genotype on the effects of the phytocannabinoids delta-9-tetrahydrocannabinol, cannabidiol or a combination of both on induction of psychotic symptoms, endocannabinoid levels in human body fluids, neuronal processing, and neural oscillations. In addition the effects of the phytocannabinoids on lipid levels in serum and cerebrospinal fluid, cognition, neuronal processing assessed by fMRI as well as D2-receptor availability assessed by [18F] desmethoxyfallypride.

Inclusion Criteria:

• Informed consent given by the subject
• Healthy young man (age between 18 and 45) insightful to the study (WST> 95)
• Right handedness
• At least one time consumption of Cannabis but less than 10 times/ per lifetime, no consumption of other psychotropic agents (despite coffee or nicotine), no alcohol abuse
• Negative drug-screening at the time of screening
• Body Mass Index between 18 and 30

Exclusion Criteria:

• Lack of accountability
• Participation in other interventional trials
• Severe medical or neurological illness, especially cardiovascular, renal, advanced respiratory, hematological or endocrinological failures or infectious diseases (acute hepatitis A, B or C or HIV) assessed at the time of the screening by the subject's history, clinical examination and laboratory testing, at the discretion of the investigator
• Any known psychiatric illness in the participant's history
• Known family history concerning psychiatric disorders
• Cannabis consumption within the last six months
• Consumption of any illegal drugs (except cannabis in history, see above)
• Intake of interfering medication, at the discretion of the investigator
• High intracranial pressure
• Any disorders in stereoscopic vision (measured by the TNO-Test, Lamerics, Utrecht) or hearing deficits
• Contraindications due to the Investigators Brochure Contraindication for Magnetic Resonance Imaging (e.g. cardiac pacemaker, claustrophobia, attached brace, in body metal, tattoos) or lumbar puncture (e.g. local or systemic infection, disturbance of blood coagulation, medication with anticoagulants like Phenprocoumon) or contradiction for the PET-CT method and the radiopharmaceutical