Marijuana is the most commonly used illegal drug in the United States; more than 2 million Americans either abuse or are dependent on the drug. Therefore, there is a clear need for treatment options. Past research on marijuana treatments has focused on alleviating withdrawal symptoms. Minimal focus has been placed on how altering craving effects may play a role in treating marijuana addiction. Treatment with THC, a component of marijuana that causes the "high" sensation, may reduce marijuana cravings. This study will evaluate the subjective and physiological responses to marijuana-related cues versus non marijuana-related cues in marijuana users who have been pre-treated with THC.