Attention deficit hyperactivity disorder (ADHD) is a chronic condition, and if left untreated, it can set a child up for a lifetime of difficulties in learning and forming relationships. At least that is the assumption that has guided the popular approach to treating ADHD for decades. But new research suggests that ADHD might be much less persistent than previously thought.

A team led by Prudence Fisher and J. Blake Turner, both at Columbia University and the New York State Psychiatric Institute, reviewed the records of nearly 1,500 children from four studies that had used a standard diagnostic interview to screen for ADHD. They found that a majority of children who qualified for an initial diagnosis had lost their diagnosis by two years later.

ADHD has three subtypes: hyperactive, inattentive and both combined. More than half the children with the hyperactive and inattentive subtypes of the disorder had reverted to no ADHD at a two-year follow-up interview. Although the combined subtype was more persistent, between 18 and 35 percent of children in that group had also lost their diagnosis by the follow-up. Kids with many symptoms and significant impairment were just as likely to lose their diagnoses as children with milder forms of the disorder. Nor were the losses attributed to successful treatment.

To Turner, the findings suggest that the current definition of ADHD would benefit from greater speci­ficity. If a disorder is, by definition, long-lasting, “then we are over­diagnosing ADHD,” Turner says. He and Fisher are advisers to the ongoing revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM), the handbook of guidelines for diagnosing psychiatric disorders. Turner recommends a cautious ap­proach to labeling and medicating kids whose behaviors, though irritating to many adults, are likely to be transient.

Joel Nigg, a professor of psychiatry at the Oregon Health and Science University who was not involved with the study, says that the finding reflects our evolving understanding of ADHD. Fifty years ago experts believed that most children “grew out of it.” In the 1970s and 1980s new studies ap­peared to show that ADHD is lifelong. The truth might lie so­mewhere in between. “The corrective here,” Nigg says, “may be that it’s chronic sometimes, a fluctuating condition in other cases, and it may be that some kids get better.”