Objective: Anorexia is one of the most common adverse events seen with methylphenidate used for the treatment of attention deficit hyperactivity disorder (ADHD). The aim of this study is to investigate neurobiological processes underlying the side effects such as anorexia and/or weight loss that develope associated with extended release methylphenidate used to treat children and adolescents with ADHD.
Method: We included 30 cases (patient group) between the ages of 6 and 18 years old, who had recently been diagnosed with ADHD and 20 healthy children (control group), who were at the same age and gender as in the patient group. The patients with ADHD were assessed with Barkley Stimulant Side Effect Assessment Form after they had received extended release methylphenidate for two months. The levels of leptin, ghrelin, adiponectin and brain-derived neurotrophic factor (BDNF) were measured in blood samples of healthy control group and in blood samples of patients with ADHD collected before and after extended release methylphenidate (after two-month treatment).
Results: There were no significant differences in leptin, ghrelin, adiponectin and BDNF levels between the healthy control group and the untreated patients, who had recently been diagnosed with ADHD. The most common adverse events occurred in the ADHD group after 2-months treatment included loss of appetite (70%), weight loss (66.7%), difficulty in falling asleep (53.3%), and headache (46.7%). No significant difference was observed in leptin levels but significant differences in ghrelin (p<0.05), adiponectin (p<0.001) and BDNF (p<0.05) levels were found between the measures performed after methylphenidate treatment and before methylphenidate treatment of patients with ADHD.
Conclusion: As a result, no significant differences were found in levels of biomolecules that are known to be responsible for regulating appetite and nutrition of patients with ADHD, who did not receive treatment compared to healthy control group. Extended release methylphenidate treatment has been shown to affect levels of biomolecules that are responsible for regulating appetite and nutrition of patients with ADHD. The changes in adiponectin levels is thought to be underlying neurobiological mechanism of decreased appetite and/or weight loss due to methylphenidate treatment. Studies to be performed after longer term treatments with large sample groups and investigation of these findings will present new data about neurobiological mechanisms underlying anorexia and/or weight loss that are associated with extended release methylphenidate.