 Experimental Design and Methods: After being medically cleared and giving written informed consent, each participant will undergo a structural MRI scan of the brain, and undergo an fMRI scanning session, which will include administration of the distress tolerance and relevant control tasks. Physiological response to the tasks, including heart rate, blood pressure, galvanic skin conductance, and salivary cortisol concentrations will be monitored throughout the fMRI scan. Follow-up assessments on control and cocaine dependent participants will occur at 1, 3, 6, and 12 months after the baseline assessment. Genetic data collected under the aegis of protocol 10-DA-N457 will be compared with data collected under this study. 