[Methylphenidate, tics and compulsions].

Obsessive compulsive (OC) symptoms following methylphenidate (MPH) administration are seldom reported and usually not even mentioned among its adverse effects. We report here a case of MPH-induced OC symptoms which began ten months after the treatment was initiated and that were exacerbated 14 months later. This delay and the symptoms fluctuations might lead out of the right diagnostic though tic occurrence could then correct. Cross-sensitization between stress and psychostimulants might as well explain the long delayed onset of obsessive compulsive symptoms as their fluctuation both along time and contexts.