METHYLPHENIDATE DISCONTINUATION AND REINITIATION DURING LONG-TERM TREATMENT OF CHILDREN WITH TOURETTES DISORDER AND ATTENTION-DEFICIT HYPERACTIVITY DISORDER - A PILOT-STUDY

The purpose of this study was to assess the effect of long-term treatm ent with methylphenidate (MPH) on tie symptom frequency and severity. Five boys, ages 8 to 14 years, with Tourette's disorder and attention- deficit hyperactivity disorder were studied in an ON, OFF, ON design. Subjects were admitted to a research unit for observation and videotap ing. At Visit 1, blinded 5-min tic counts and nonblinded clinicians' t ic ratings (Challenge-Yale Global Tic Severity Scale [C-YGTSS]) were o btained at 7 time points throughout the day, while subjects continued to take their clinically prescribed doses of MPH (mean daily dose 0.5 mg/kg, range 0.2 to 1.0). MPH was discontinued following Visit 1. Two weeks later each subject was readmitted for Visit 2, which was identic al to Visit 1 except that no MPH was given. MPH was then reinitiated, and each subject was readmitted 4 weeks later for Visit 3. Mean blinde d tic counts and C-YGTSS scores were significantly higher at Visits 1 and 3 (on MPH) than Visit 2 (off MPH). Clinically meaningful changes w ere observed in all five subjects. Tic frequency and severity diminish ed after discontinuation of MPH for 2 weeks and increased after reinit iation of MPH for 4 weeks, despite the relatively low doses employed. Further study is required to reconcile these findings with other recen t short-term treatment studies that have found no consistent effect of stimulant medication on tic severity. For now, caution and close moni toring appear warranted when children with tic disorders receive long- term treatment with stimulant medication.