Obsessive compulsive disorder (OCD) as well as related disorders such as body dysmorphic disorder, tic disorder, and trichotillomania are all common and often debilitating. Although treatments are available, more effective approaches to these problems are needed. Thus this review article presents what is currently known about OCD and related disorders and suggests that understanding OCD more broadly as a compulsive disorder may allow for more effective treatment options. Toward that goal, the review presents new models of psychopharmacology and psychotherapy, as well as new brain stimulation strategies. Treatment advances, grounded in the neuroscience, have promise in advancing treatment response for OCD as well as other disorders of compulsivity.