ADHD Drug Works and Doesn't Worsen Comorbidities

Kenneth Bender

An effective ADHD drug did not aggravate other conditions.

The efficacy of atomoxetine (Strattera/Eli Lilly) for attention-deficit/hyperactivity disorder (ADHD) has been demonstrated in patients with and without comorbid psychiatric conditions, and a new review suggests that the treatment does not adversely affect those conditions.

Although the reviewers found that up to 52% of children and adolescents and 87% of adults with ADHD are estimated to have other psychiatric conditions, they found no review of how those conditions may impact the therapeutic effect of atomoxetine on ADHD, or are affected by the treatment.

"To the best of our knowledge, there are no comprehensive reviews collectively covering the common ADHD comorbidities in relationship to ADHD treatment for children and adults," remarked reviewers David Clemow, PhD, senior clinical research scientist, and colleagues at Eli Lilly.

Clemow and colleagues identified 50 studies with atomoxetine treatment of ADHD in subjects with at least one comorbid disorder, with 37 involving children and adolescents and 13 in adults. The most common comorbid disorders were anxiety, depression, mood disorders and substance use disorder.

In the two studies of atomoxetine in children with anxiety, the medication was associated with improvement of ADHD symptoms, without apparent increase in symptoms of anxiety. Several studies in adults with comorbid anxiety evidenced improvement in ADHD with either no effect or improvement in anxiety symptoms.

The reviewers emphasize, however, that those studies in which anxiety symptoms improved are not a measure of atomoxetine efficacy for that condition.

"It is important...to differentiate usage of atomoxetine when a comorbidity is present from usage in that comorbid condition alone," Clemow and colleagues caution. "Atomoxetine does not improve symptoms of anxiety in patients with anxiety disorders but without ADHD."

Atomoxetine treatment effect for ADHD was comparable in children with or without depressive symptoms. In one randomized controlled trial (RCT) there was no change in depressive symptoms. In another, depressive symptoms improved along with those of ADHD, but the reviewers noted that there had been no placebo control. Studies in adults found benefit for ADHD without change in the assessments of depression.

The reviewers found only one RCT and one open-label prospective study of an ADHD child-adolescent population with a substance use disorder. Atomoxetine effect for ADHD did not separate from the comparator or the control condition in either study, and had no apparent effect on substance use.

In the studies of adults with comorbid substance use disorder, atomoxetine was associated with improvement in ADHD, but with mixed results on substance use. In one RCT, atomoxetine significantly reduced cumulative days of heavy drinking, but did not reduce latency to relapse of heavy drinking. In other studies, atomoxetine improved ADHD symptoms while not affecting use of cannabis in one population, or of cocaine use in another.

"In the studies reviewed, there is no evidence of worsening of any of the comorbidities examined, and in some cases, there is significant improvement, Clemow and colleagues report.

The review of atomoxetine treatment of ADHD with comorbid psychiatric conditions was published on-line February 3 in Neuropsychiatric Disease and Treatment, "Efficacy of Atomoxetine in the Treatment of Attention-deficit Hyperactivity Disorder in Children and Adult Patients with Common Comorbidities."

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