Attention deficit hyperactivity disorder, or ADHD, affects 11 percent of boys and 4.4 percent of girls. The patch delivers methylphenidate through the skin and is sold under the brand name Daytrana by Shire PLC. (NASDAQ:HPGY)

"The findings are significant because only a relatively modest amount of work has been done to examine the effects of ADHD treatments by gender," said Dr. Robert Findling of Case Western Reserve University in Cleveland, who led the investigation, He said parents "need to recognize ADHD symptoms present differently in girls than in boys."

Studies have found girls tend to show less disruptive ADHD symptoms such as inattention, while boys tend to exhibit hyperactivity and impulsivity.

In the study of 326 children, adverse events were mild or moderate and no clinically significant differences in adverse events were noted between boys and girls. In one measure of change, boys showed a 41 percent improvement in symptoms that define ADHD and girls showed a 23 percent improvement.