Investigating the Acute Effects of THC on Functional Brain Systems

Inclusion Criteria: * History of mild cannabis use for at least one year (\<1/week and ≥ 4/year) * History without psychotic experiences after cannabis use * Age between 18 and 45 years * Right-handedness, assessed with the Edinburgh Handedness Inventory * Written informed consent of the subject Exclusion Criteria: * Any clinical significant abnormality of any clinical laboratory test, including urinary drug screening * Impaired physical health evaluated by medical history, physical (including neurological) examination and screening laboratory tests * History of clinically significant psychiatric or neurological illness * History of clinically significant psychiatric or neurological illness in first- or second-degree relatives * History of alcohol and/or drug abuse (DSM-IV criteria) * Body Mass Index (B.M.I.) \<18 kg/m2 or \>28 kg/m2 * Paranoid ideation or psychoticism on SCL-90 * Any subject who received any investigational medication within 90 days prior to the start of the study or who is scheduled to receive an investigational drug * The use of any medication within three weeks prior to the start of the study, except for paracetamol * Positive HIV or Hepatitis B/C test * Blood donation within 3 months before the start of the study * Claustrophobia * Metal objects in or around the body (braces, pacemaker, metal fragments)