Effects of Citicoline on Brain Function and Behavior in Marijuana-Dependent Individuals

The Three Aims of this study are (only studies for Aim 1 were completed) 1. Measure the impact of citicoline on marihuana use patterns in subjects' individualized natural settings and responses to marihuana challenge using functional brain MRI scans. Hypothesis - 2 g/day citicoline will produce greater reductions in marihuana use and craving in heavy marihuana users than placebo citicoline over a 8-week treatment period as measured in their natural environments. The same participants will experience greater improved brain activation patterns and an improvement in cognitive functioning compared to placebo controlled subjects. 2. Measure the effects of citicoline on marihuana absorption and metabolism and determine if these changes parallel changes in subjective and physiological responses in a laboratory setting. Hypothesis - Chronic (8 weeks) treatment with 2 g/day citicoline will produce increases in subjective and physiological effects of both acute marihuana smoking and placebo marihuana smoking compared to chronic placebo citicoline. Citicoline will have no effect on marihuana pharmacokinetics. 3. Measure the effects of citicoline on marijuana-induced cue-induced craving and brain electrical activity (EEG). Hypothesis - Chronic (8 weeks) treatment with 2 g/day citicoline will reduce objective measures of marijuana cue-reactivity, and subjective reports of craving in response to marihuana cues will also be attenuated compared to chronic placebo citicoline treatment.