Choosing medication to help distressed patients is not simple. The best outcomes occur when diagnoses are sufficiently well developed to suggest a pattern of impairment, when mechanisms of the medications are well understood, when the client can accurately assess behaviors that will change as pathology improves, and when individual needs and risks are considered. This talk will take a mechanistic approach to how groups of behavioural medications work, and will choose a handful of medications as exemplars that can be commonly used.