The goal of this placebo-controlled study is to learn about the neural mechanisms underlying the acute effects of the synthetical cannabinoid JWH-018 in healthy, occasional cannabis users. It aims to assess neural underpinnings of neurocognitive impairments and psychotomimetic symptoms expected during the intoxication. Neuronal changes similar to those seen in cannabis intoxication are expected, such as altered neurotransmission and loss of functional connectivity within the mesocorticolimbic circuit. MRS, fMRI and blood parameters will be used for assessment. Participants will be asked to complete cognitive tasks and subjective questionnaires related to the subjective experience of the drug.

Inclusion Criteria:

• sufficient experience with cannabis
• Age between 18 and 40 years
• Free from psychotropic medication
• Good physical health
• Absence of any major medical, endocrine and neurological condition
• Normal weight, body mass index (weight/height^2) between 18 and 28 kg/m^2
• Written Informed Consent
• Good knowledge and understanding of the English language
• refrain from taking illicit psychoactive substances during the study
• willing to drink only alcohol-free liquids and no caffeinated beverages from 24 hours prior to dosing day, as well as during the study day
• Participants must be willing not to drive a traffic vehicle or to operate machines within 24 h after substance administration.

Exclusion Criteria:

• History of drug addiction
• Pregnancy or lactation or pregnancy planned during study participation
• Hypertension (diastolic > 90 mmHg; systolic > 140 mmHg)
• Current or history of psychiatric disorder (determined by the medical questionnaire and medical examination)
• Any chronic or acute medical condition
• History of cardiac dysfunctions (arrhythmia, ischemic heart disease,…)
• For women: no use of a reliable contraceptive
• Tobacco smoking (>20 per day)
• Excessive drinking (>20 alcoholic consumptions per week)
• Simultaneous participation in another clinical trial
• fMRI contraindications