The majority of past research on marijuana treatment has targeted the alleviation of withdrawal symptoms. Minimal focus has been placed on how altering craving effects may play a role in treating marijuana addiction. Treatment with tetrahydrocannabinol (THC), the main ingredient in marijuana responsible for its reinforcing effects, may decrease marijuana cravings. The purpose of this study is to evaluate the effect of THC pre-treatment on responses to marijuana-related cues versus non marijuana-related cues in individuals addicted to marijuana.