N-acetylcysteine for the Treatment of Cannabis Dependence: Working Mechanisms

Inclusion Criteria: * Current DSM-IV diagnosis of cannabis dependence, \>1 week detoxified and abstinent; * Able to provide written informed consent and to comply with study procedures. * Dutch speaking (Dutch as primary language). Exclusion Criteria: * Currently dependent on any substance other than cannabis, alcohol or nicotine; * History of any major internal disease (including diabetes, cardiovascular disease, lung disease, liver or kidney disease); * An active or any history of neurological disorder, including but not limited to seizure disorder, epilepsy, stroke, neurological disease, cognitive impairment, head trauma with prolonged loss of consciousness (\>10 minutes), or migraine headaches; * An active or a history of a psychiatric disorder including, but not limited to, depression, schizophrenia, bipolar disorder, anxiety, or other psychiatric disorders; * Asthma; * Known hypersensitivity or allergy to n-acetylcysteine, or receiving chronic therapy with medication that could interact adversely with n-acetylcysteine within 30 days prior to randomization (i.e., nitroglycerin, ACE inhibitors or antihypertensive drugs, anti-coagulants); * Exclusion criteria for MRI: having metal in the body and/or having claustrophobia