Does Treatment of ADHD Lead to Substance Abuse?

One of the long-standing concerns amongst professionals and parents alike is the possibility that early treatment of attention deficit disorder (ADHD) with stimulant medication (such as Ritalin or Adderall) could possibly lead to later problems. New research suggests these concerns are largely unfounded, with one possible exception.

The studies were published in the latest issue of the American Journal of Psychiatry and both studies largely showed no positive association between the use of stimulant medication in children and an increased risk of substance abuse later on in life. The first study, Biederman et. al. (2008) reported on the 10-year followup of 112 children who were between 6 and 17 years-old when first entered into the study:

In a longitudinal sample of male subjects diagnosed with ADHD in childhood and followed up for 10 years into their young adult years, we found no evidence that prior treatment with stimulants was associated with subsequent increased or decreased risk for alcohol, drug, or nicotine use disorders. Further, we did not detect any significant association between age at stimulant treatment onset and subsequent substance use disorders or any associations between the duration of stimulant treatment and subsequent substance use disorders. These findings support the hypothesis that stimulant treatment does not increase the risk for subsequent substance use disorders.

The second study, Mannuzza et. al. (2008) showed more mixed results. While they did find an association between stimulant use for the treatment of ADHD and later substance use disorders, it was accounted for by a third, unexpected factor — antisocial personality disorder. Subjects who didn’t start stimulant medication until they were between ages 8 and 12 had greater substance abuse that was mediated by an increase in antisocial personality disorder in adulthood. Subjects with early stimulant treatment — before the age of 8 — did not differ from comparison subjects in lifetime rates of non-alcohol substance use.

So kids who are diagnosed and begin medication treatment later in childhood may be at more risk for later substance abuse because of the development of an antisocial personality disorder. There really is no adequate explanation for the greater prevalence of antisocial personality disorder in the later treatment group compared to the earlier treatment group, which the journal’s accompanying editorial notes:

The authors discuss the possibility that early stimulant treatment of ADHD may have a protective effect toward the emergence of conduct disorder, which usually precedes antisocial personality disorder and increases the risk for drug abuse. However, this hypothesis is not supported by early findings from the Multimodal Treatment Study of ADHD, in which treatment with stimulants in this prospective follow-up study did not selectively reduce conduct disorder, or by national trends over the past decade, when there has been a dramatic fivefold increase in the treatment of ADHD children in the United States with stimulants but no change in the prevalence of conduct disorder.

The upshot is that these studies confirm a large body of evidence that suggests there is little direct connection between the prescription of stimulant medications to children for ADHD and later substance abuse issues. The second study did find a link, but it seems to be because of the development of antisocial personality disorder. Further research is needed to determine the link between stimulant medications and this disorder.

The accompanying editorial puts the results into further perspective.

References:

Biederman J, Monuteaux MC, Spencer T, Wilens TE, MacPherson HA, Faraone SV (2008). Stimulant therapy and risk for subsequent substance use disorders in male adults with ADHD: a naturalistic controlled 10-year follow-up study. Am J Psychiatry, 165, 597 — 603.

Mannuzza S, Klein RG, Truong NL, Moulton JL III, Roizen ER, Howell KH, Castellanos FX. (2008). Age of methylphenidate treatment initiation in children with ADHD and later substance abuse: prospective follow-up into adulthood. Am J Psychiatry, 165, 604 — 609.