Original Research Individual Change in Methylphenidate Use in a National Sample of Children Aged 2 to 11 Years

Objectives: To determine methylphenidate use in children aged 2 to 13 years. To provide age- and sex-specific estimates of methylphenidate initiation and cessation during a 2-year period. Method: Data from 2 cycles of a Canadian household survey yielded a sample of over 10 000 children aged 2 to 11 years at Cycle 1 who continued to participate at Cycle 2. We used logit modelling to estimate Cycle 2 methylphenidate use, methylphenidate use over a 2-year period, and methylphenidate initiation and cessation from Cycles 1 to 2. Results: In 1996 and 1997, methylphenidate use ranged from 0.32 % to 6.31 % among children aged 4 to 13 years. School-aged boys were more likely than girls to use methylphenidate. Odds were greater for boys aged 6 to 7 years than for boys aged 4 to 5 years; they were also greater for boys aged 10 to 11 years than for boys aged 12 to 13 years. Almost 1 % of children used methylphenidate at both data cycles. Odds of Cycle 2 methylphenidate use were 135 times greater for children using methylphenidate at Cycle 1, compared with nonusers. Methylphenidate initiation ranged from 0.20 % to 3.34%, and school-aged boys had higher initiation rates than girls. Cessation rates ranged from 18 % to78%, and there were no statistically significant differences by age and sex. Conclusions: Methylphenidate prevalence findings are consistent with past studies. We found an age-by-sex interaction on methylphenidate use. We also found both continuity and discontinuity in methylphenidate use. (Can J Psychiatry 2005;50:144–152) Information on funding and support and author affiliations appears at the end of the article