 Objective: Drugs of abuse have cognitive and affective effects that may contribute to the inception and maintenance of their use. In order to measure these effects, psychological tests suitable for use both in and outside the fMRI scanner need to be developed and validated. Thus, the objective of this protocol is to allow for the development, assessment and refinement of cognitive and affective tasks and determination of their practical feasibility and efficacy for both MRI and non-MRI application. 