Ginkgo biloba for attention-deficit/hyperactivity disorder in children and adolescents: a double blind, randomized controlled trial.

BACKGROUND: Although stimulants are highly effective in controlling the symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD), some children will not respond to, or are intolerant of stimulants. Thus, the desire for safe and effective nonstimulant medications has risen during the past several years. Ginkgo biloba has been suggested in the treatment of dementia and memory impairment. We hypothesized that G.biloba would be beneficial for treatment of ADHD, and this could be evaluated in a double blind, randomized, parallel group comparison of G.biloba (Ginko T.D. Tolidaru, Iran) and methylphenidate.

METHODS: Fifty outpatients (39 boys and 11 girls) with a DSM-IV-TR diagnosis of ADHD were study population of this trial. Subjects were recruited from an outpatient child and adolescent clinic for a 6 week double blind, randomized clinical trial. All study subjects were randomly assigned to receive treatment using tablet of Ginko T.D. at a dose of 80-120 mg/day depending on weight (80 mg/day for <30 kg and 120 mg/day for >30 kg) (group 1) or methylphenidate at a dose of 20-30 mg/day depending on weight (20 mg/day for <30 kg and 30 mg/day for >30 kg (group 2) for a 6 week double blind, randomized clinical trial. The principal measure of outcome was the Teacher and Parent ADHD Rating Scale- IV. Patients were assessed at baseline and at 21 and 42 days after the medication started.

RESULTS: Significant differences were observed between the two groups on the Parent and Teacher Rating Scale scores. The changes at the endpoint compared to baseline were: -6.52+/-11.43 (mean+/-S.D.) and -15.92+/-11.44 (mean+/-S.D.) for Ginko T.D. and methyphenidate, respectively for Parent ADHD Rating Scale. The changes at the endpoint compared to baseline were: -0.84+/-6.79 (mean+/-S.D.) and -14.04+/-8.67 (mean+/-S.D.) for Ginko T.D. and methyphenidate, respectively for Teacher ADHD Rating Scale. The difference between the Ginko T.D. and methylphenidate groups in the frequency of side effects was not significant except for decreased appetite, headache and insomnia that were observed more frequently in the methylphenidate group.

CONCLUSION: The results of this study suggest that administration of G.biloba was less effective than methylphenidate in the treatment of ADHD.