Research conducted on rats suggests that the misdiagnosis of attention deficit hyperactivity disorder (ADHD) combined with prescription drug use in children may lead to a higher risk of developing depressive symptoms in adulthood. The research, carried out by the National Institutes of Health and McLean Hospital/Harvard Medical School, was presented at the annual American College of Neuropsychopharmacology conference in Puerto Rico. "Attention-deficit hyperactivity disorder can be a serious medical problem for children and their parents," says lead researcher William Carlezon. "While Ritalin is an effective medication that improves the quality of life for many children with ADHD, accurately diagnosing and identifying the correct treatment regimen for the disorder is essential, especially when considering health effects that can last through adulthood."
The researchers examined the effects of exposing rats to Ritalin during early development. They exposed normal rats to twice-daily doses of Ritalin during a period that is equivalent to approximately 4-12 years of age in humans. Examining the behavior during adulthood, Carlezon and co-researcher Susan Andersen conducted several types of tests that all showed that the animals had a reduced ability to experience pleasure and reward. In addition, they found that the animals exposed to Ritalin during pre-adolescence were more prone to express despair-like behaviors in stressful situations as adults. Overall, the animals showed more evidence of dysfunctional brain reward systems and depressive-like behaviors in adulthood.
The researchers say these findings are critical because they suggest that Ritalin can have long-term consequences on normal-functioning brains. The study is particularly relevant when considering the difficulty in correctly diagnosing children with ADHD. In 1999, approximately 90 percent of children diagnosed with the disorder were taking Ritalin, with children beginning drug therapy at younger ages today, even during preschool in some instances. There is increasing evidence to suggest that correct diagnosis of ADHD is of the highest importance - children who are misidentified as having ADHD and subsequently placed on prescription drug therapy could face possible impaired brain performance when older.
"Ritalin can be highly effective in the treatment of ADHD, but our work highlights the importance of getting a proper diagnosis", states Carlezon. "Although individuals such as teachers and coaches can assist in identifying children with the disorder, an experienced health care professional is best-trained to make the final assessment and recommend avenues of treatment."
