Attention Deficit Disorder: To Treat or Not to Treat?

Abstract & Commentary

Synopsis: Two recent studies appear to swing the balance toward early and effective therapy of patients with ADHD. The administration of "speed" to children with ADHD clearly does not breed "junkies" later in life, as was once thought.

Source: Biederman J, et al. Pharmacotherapy of attention-deficit/hyperactivity disorder reduces risk for substance use disorder. Pediatrics 1999;104:e20.

Attention deficit hyperactivity disorder (adhd) is a common behavioral syndrome, with an estimated prevalence of 3-5%. ADHD is characterized by motor overactivity, impulsivity, and inattention, among other features. The diagnosis of ADHD is often made "by committee" with impressions of parents, teachers, and various clinicians, including neurologists, playing a role. These impressions can be bolstered by psychometric tests, but no test is entirely specific. With these diagnostic uncertainties, particularly in younger patients or in milder cases, the decision to treat patients with ADHD with daily stimulant medications, such as methylphenidate (Ritalin), can be a difficult one.

Two recent papers highlight two potential risks, one short-term and one long-term, of withholding appropriate treatment of ADHD. DiScala and colleagues1 retrospectively examined the National Pediatric Trauma Registry (NPTR) for injury characteristics of patients diagnosed with ADHD to those with no other pre-existing condition. The NPTR database includes children admitted to the hospital with acute injury, regardless of severity, and includes extensive information on preinjury medical history. DiScala et al found that patients with ADHD (n = 240) were more likely to be injured as pedestrians and bicyclists, and to inflict self-injury than patients without ADHD (n = 21,902). Patients with ADHD in the registry, as compared to patients without ADHD, were more likely to be admitted with Glasgow Coma Scale scores of 9-12 (9.2% vs 3.3%) or scores of less than 8 (7.5% vs 3.4%). It is notable that 80% of the children in the ADHD group had not been receiving regular medication, so that the information largely reflects untreated ADHD.

Biederman and colleagues provide evidence for a less immediate risk of untreated ADHD, namely an increased risk for future substance abuse. This group has published extensively on the longitudinal follow-up of patients with ADHD. This particular study restricted its analysis to male patients older than age 15, and compared three groups: ADHD/medicated (n = 56), ADHD/nonmedicated (n = 19), and non-ADHD groups (n = 137). The groups were examined for the presence of alcohol, marijuana, hallucinogen, cocaine/stimulant, or tobacco use of dependency at baseline and four-year follow-up. Biederman et al found that the incidence of any of the substance abuse disorders at four-year follow-up was 6.3-fold more likely in patients with unmedicated ADHD as compared to the non-ADHD group. Strikingly, stimulant drug treatment of ADHD had a protective effect, bringing the incidence of any substance abuse disorder down to levels comparable to non-ADHD groups. Unmedicated ADHD seemed to have the most powerful effect on future alcohol or cocaine/stimulant use and no significant effect on hallucinogen or tobacco use, so that there may be certain use patterns in these patients.

Comment By Rosario Trifiletti, MD

Although these studies are complex and their interpretation not completely straightforward, they appear to swing the balance toward early and effective therapy of patients with ADHD. The administration of "speed" to children with ADHD clearly does not breed "junkies," as was once thought (and many parents still believe).

The side effects and limitations of stimulants are better understood now than a decade or two ago. For example, it is now clear that while the risk of patients developing a tic disorder with methylphenidate treatment may be as high as 10%,2 most cases are transient and only about 1% of patients develop features of Tourette syndrome. Furthermore, methylphenidate can be safely and effectively used in the great majority of patients with chronic tic disorders,3 and does not influence the severity of tics in most patients. (Dr. Trifiletti is Assistant Professor of Neurology & Pediatrics, Department of Neurology, Weill Medical College of Cornell University.)

References

1. DiScala C, et al. Injuries to children with attention deficit hyperactivity disorder. Pediatrics 1998;102: 1415-1421.

2. Lipkin PH, et al. Tics and dyskinesias associated with stimulant treatment in attention-deficit hyperactivity disorder. Arch Pediatr Adolesc Med 1994;148:859-861.

3. Gadow KD, et al. Long-term methylphenidate therapy in children with comorbid attention-deficit hyperactivity disorder and chronic multiple tic disorder. Arch Gen Psychiatry 1999;56:330-336.