An 8-year follow-up study of profiles and predictors of methylphenidate use in a nationwide sample of boys.

Objectives: To identify methylphenidate profiles over several years in a national sample of boys and examine behavioral and sociodemographic predictors of use.

Study Design: Five cycles of a Canadian survey were used, resulting in 1447 boys followed from 2 to 3 years to 10 to 11 years. Mother reports of boys' methylphenidate use from 4 to 5 years to 10 to 11 years were used to identify profiles over time. Mother-reported sociodemographic and child behavior data at 2 to 3 years were then used to predict methylphenidate profiles.

Results: Three methylphenidate profiles were identified: no use (87.2%); slow-rising, intermittent (11.2%); and fast-rising, stable (1.6%). Sociodemographic variables were not significant predictors. Boys with greater hyperactivity-impulsivity, greater inattention, and less disruptive behavior were more likely to belong to the fast-rising, stable methylphenidate profile. Although 13% of boys were using methylphenidate over time, there were 2 heterogeneous profiles. In the first profile, there were very few initial users followed by a steady increase in the number of boys using methylphenidate over time. Among these boys, however, use was inconsistent over time. In the second profile, there was a sharp onset of methylphenidate use on school entry, followed by consistent use thereafter.

Conclusions: These findings have implications for the treatment effectiveness of attention deficit-hyperactivity disorder symptoms. It is important to continue examining the role of disruptive behavior because its co-occurrence with attention deficit-hyperactivity disorder symptoms and methylphenidate use is complex.