54-year-old female patient who came to hospital due to psychopathological decompensation of her Obsessive-Compulsive Disorder (OCD), after 35 years under follow-up. Parkinson´s disease. Psychopharmacological treatment: sertraline 100 mg (1-0-0); lorazepam 2 mg (1-1-1); Levodopa/carbidopa 100/25 mg (1-1-1). Distressed at first examination. She described increase in rituals, important intake restriction, weight impact and difficulties in home management with functional repercussions. Psychopathological exploration: conscious, oriented, and approachable. Circumstantial speech with no obsessive ideas. Increased frequency of repetitive behaviours led to a functional deterioration, becoming dependent for activities of daily living. Elevated anxiety. No major mood disorder. No psychotic symptoms. Bradykinesia. Hypophagia without anorexia. Admission is carried out. Good evolution: improvement in motor symptoms and intake restoration. No changes in repetitive behaviours.

To discuss the differential diagnosis between OCD and Frontotemporal Dementia.

Repetitive behaviours were initially understood as rituals typical of OCD. However, the absence of both a fixed pattern of behaviour and a structured obsessive ideation, made us consider the possibility of frontal perseveration behaviours. For this reason, a neuropsychological evaluation and a functional neuroimaging test were performed: Test Mo-CA: 9/30 with striking failures in executive functions. SPECT: mild uptake defect in the left frontotemporal region.

Finally, in view of the impairment in executive functions and the frontal defects in neuroimaging, we change the initial diagnosis of OCD towards a Neurocognitive Disorder of probable frontotemporal origin.

The presented case evidenced the importance of differentiating obsessive compulsions from frontal perseverance to guide the differential diagnosis, given the implications for therapeutic management and prognosis.

No significant relationships.