Review of: Shaywitz S et al, J Child Adolesc Psychopharmacol 2016;27(1):19–28.

Dyslexia, a learning disability characterized by difficulty in reading skills, is highly prevalent, with rates between 5% and 17%. Treatments include non-medical interventions, which have limited success. Research suggests a critical role for attentional mechanisms in the development of dyslexia. Previous small studies have shown stimulants as well as atomoxetine may improve reading in patients who have comorbid attention deficit hyperactivity disorder and dyslexia (ADHD+D). This new study is a larger, placebo-controlled trial to evaluate atomoxetine’s efficacy in patients with ADHD+D as well as those with dyslexia or ADHD only.

The researchers randomized 209 children and adolescents, aged 10–16 years, into a placebo group (n = 89) and a treatment group (n = 120). The placebo group consisted of dyslexia-only (n = 29) and ADHD+D patients (n = 60), while the treatment arm consisted of dyslexia-only (n = 29), ADHD+D (n = 64), and ADHD-only (n = 27) patients. The patients were treated with either atomoxetine (starting at 0.5 mg/kg daily for 3 days, then 1.0–1.4 mg/kg per day) or placebo. Reading abilities were measured with a variety of standardized tests after 16 weeks. Both ADHD+D and dyslexia-only patients receiving atomoxetine showed statistically significant improvement in phonologic processing (sounding out words), basic reading skills, and reading vocabulary compared to those receiving placebo. Effect sizes were moderate to high (ranging from 0.5 to 0.73), and literacy improvement in comorbid patients was not correlated with improvements in ADHD symptoms.

CCPR’s take
While the study shows promising results, it’s not clear whether the improvement seen is clinically significant, whether it would be seen in a range of kids with varying levels of dyslexia, or whether it would be sustained over time. Nonetheless, atomoxetine is a well-tolerated medication and is one of the few agents shown to be helpful for dyslexia. Readers should know that the study was funded by Eli Lilly, the manufacturer of Strattera (atomoxetine), although there were no obvious signs of bias in research design or analysis.