Adults Benefit From Drug Treatment for ADHD

May 21, 2003

Roberta Friedman, PhD

May 21, 2003 (San Francisco) - Adults who refer themselves for treatment for attention deficit/hyperactivity disorder (ADHD) respond to methylphenidate, and the medication continues to work over a six-month period, as shown by a randomized, placebo controlled study.

Session moderator Timothy Wilens, MD, associate professor of psychiatry at Harvard University in Cambridge, Massachusetts, called the study "extraordinarily important. It evaluates longer-term effects of treating ADHD in adults."

Particular strengths of the study, added Dr. Wilens, who commented on the study for Medscape, include its use of "clinically significant doses, and its placebo control. Findings of global, sustained improvement [in the trial] are heartening."

Thomas Spencer, MD, associate professor of psychiatry at Harvard, reported on his study results here yesterday at the American Psychiatric Association annual meeting.

The 100 patients who presented for the study had an average IQ of 113. Despite this evident intelligence, Dr. Spencer told attendees at a symposium, many had repeated a grade in school, and they reported to investigators that they had needed extra help with classes.

Dr. Spencer, who is assistant chief of the pediatric psychopharmacology research program at Massachusetts General Hospital in Boston, speculated to the audience that perhaps "others [with lower IQs] may not realize the ADHD as the problem" that they are having at work and at home.

The average age of study participants was 39 years, and 59% of participants were men. In children, ADHD is diagnosed more often in boys than in girls.

Of 121 patients randomized to receive active drug or placebo, 103 completed two weeks of the trial and 82 completed the entire six weeks.

Investigators measured response to treatment with the ADHD symptom checklist. Average score at baseline was about 35, with 20 being the threshold for diagnosing the disorder. Responses on the checklist fell below threshold by week four for participants on active drug.

Symptoms showing improvement included inattention, hyperactivity, and impulsivity.

By the third week of treatment, those 26 patients receiving placebo continued to have a score of about 30, Dr. Spencer said. Three quarters of those receiving methylphenidate responded favorably compared with 23% of those receiving placebo.

A second phase of the study looked at the responders for six months, regardless of whether they were receiving drug or placebo. Seven patients on the placebo continued, as did 46 patients on the active medication. Blinding was maintained. By week 14, 40% of patients taking placebo had dropped out.

A third phase involved abruptly stopping treatment, with participants blinded to the discontinuation. Symptoms deteriorated rapidly, Dr. Spencer noted.

Few adverse effects appeared with the therapy, with dry mouth and appetite suppression predominating. "Even robust doses of medication did not cause more anxiety" in these patients, Dr. Spencer told the attendees. He added that the lack of any persistent weight loss, a "wished for" side effect, was disappointing for the adults.

Blood pressure was raised by a few mm Hg for both systolic and diastolic, but Dr. Spencer discounted these cardiovascular effects, noting that many people approaching middle age have undetected, borderline hypertension.

Raising the heart rate by a few beats per minute also is not clinically important, said Dr. Spencer.

The use of methylphenidate in adults represents an off-label indication, Dr. Spencer told Medscape, although this use has been submitted to the U.S. Food and Drug Administration. The situation is due "in part," he said, "to the scientific community's not being sure [until recently] that ADHD exists in adults."

Adults with ADHD are sure, however, Dr. Wilens told Medscape, "these people know who they are."

The study was funded by the National Institute of Mental Health.

Dr. Spencer and Dr. Wilens both are consultants with a variety of drug companies.

APA 156th Annual Meeting. Presented May 20, 2003.

Reviewed by Gary D. Vogin, MD

Roberta Friedman, PhD, is a freelance writer for Medscape.

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