This study investigates the effect of a computerized approach/avoidance retraining (aka cognitive bias modification) over and above treatment as usual for adolescents in treatment for substance use disorders. The computerized training entails viewing pictures of drug and non-drug related stimuli, and then using the computer to make the drug pictures smaller and the non-drug pictures larger. Participants will also take part in an EEG/event-related brain potential assessment at the beginning and end of treatment to identify brain measures that are associated with treatment response.