Obsessive compulsive disorder is a severe and disabling clinical condition that usually arises in late adolescence or early adulthood and, if left untreated, has a chronic course.

To report and discuss a clinical case, followed by the authors.

Consultation of the patient's medical file, serial clinical evaluations and scientific literature review.

33 years-old male, married, degree in economics. Observed in the emergency room for having thoughts dominated by ideas of obsessive content, with a sense of self-reference, associated with recurrent compulsions as cleaning and checking rituals, consequential high levels of hopelessness and a depressive mood, with jeopardized chronobiological rhythms.

This clinical condition started seven years before and seriously undermined the patient’s autonomy. Some of the difficulties outlined by the patient are: on his way to and from work, whenever he passed by a crosswalk he would circle the following roundabout several times, to confirm that he hadn't run over any pedestrian; at the end of the day, he would go through the same path in reverse, by bicycle, to confirm that no pedestrians had been run over by him. After two years of psychopharmacological and cognitive-behavioral therapy the patient showed significant clinical improvement.

On this case, the most likely diagnosis is an Obsessive Compulsive Disorder. The particularity of this case lays on its severity, given its evolution period, the psychopathological richness demonstrated and the functional commitment of the patient; and in the significant clinical improvements observed, largely due to optimal patient adherence to treatment.