Pathological, intrusive behaviors that present in mental disorders can be viewed, alternatively, as being strongly driven by motivational urges to obtain a desired outcome (impulsive) or as repetitive, automatic and outcome-independent actions (compulsive); this distinction roughly maps on to the distinctions between goal-directed and habit-like behavior.44 Because the neural mechanisms that contribute to goal-directed and habitual actions are separable,44, 45 the view that a clinically-impairing behavior in a particular disorder is one or the other is potentially meaningful in terms of underlying pathophysiology. To some degree, many of the problematic behaviors in mental disorders in general, and in substance use disorders in particular, can arguably be viewed as impulsive or compulsive – or perhaps reflecting a transition from heightened impulsivity to heightened compulsivity.30, 31, 46, 47
