February 12th 2004
(Jan. 4, 2004) - Stimulant treatment in childhood may not increase the risk for substance use or abuse in later life, contradicting the sensitisation hypothesis, say researchers.
The neuroadaptational sensitisation hypothesis predicts that stimulant treatment in childhood confers increased risk for substance use and abuse in later life regardless of the child's mental status. Previous studies of this hypothesis have been based on naturalistic observations and yielded contradictory results.
To determine whether stimulant treatment in childhood confers increased risk for substance use and abuse in later life, Salvatore Mannuzza, PhD, and colleagues of the New York University School of Medicine, United States, performed a controlled investigation of the long-term effects of methylphenidate (Ritalin) exposure in children.
A group of children, aged 7 to 12 years, with uncomplicated developmental reading disorders studied. Forty-three were randomly assigned to methylphenidate treatment and another 66 to matching placebo for 12 to 18 weeks. Although children receiving methylphenidate were significantly older than those receiving placebo, the 2 groups were comparable on all other variables.
Additionally, 134 children without previous early behavior problems were selected and used as comparisons.
At 16-year follow-up, trained clinicians blinded to group and treatment status evaluated 94% of the children with reading disorders and 96% of the normal comparisons. No significant differences between groups were observed on the prevalence of substance use disorder for any of the 7 drug categories studied.
Furthermore, no significant group differences among substance abusers regarding age at onset, duration, or number of episodes of substance abuse and dependence.
However, while children in the methylphenidate treated and placebo groups did not differ with respect to rates of substance use (46% and 41%, respectively), normal comparisons had a significantly higher rate (60%).
"These findings are inconsistent with the notion that stimulant treatment in childhood leads to stimulant use or abuse (or, in fact, any substance use/abuse) in later life," the researchers noted.
Source: Journal of Child and Adolescent Psychopharmacology 2003 Fall;13:3:273-82. "Does Stimulant Treatment Place Children at Risk for Adult Substance Abuse? A Controlled, Prospective Follow-up Study"
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