Efficacy and Safety Study of Combination of Ginkgo Extract and Ginseng Extract(YY-162)in Children With ADHD

Inclusion Criteria: * Male and female subjects aged from 6 to 12 * Subjects must meet DSM-IV criteria for ADHD based-on the K-Schedule for affective disorder and schizophrenia(K-SADS-PL-K) interview * Subjects signed a written consent form voluntarily. * Patient 's assent to participate in the study and written informed consent form signed by one of the parents, parent surrogates, or legal guardian. * Subjects who can keep visit schedule and whose parent/ parent surrogates or legal guardian can willingly complete assessments defined in the study protocol * Subjects/parents, parent surrogates or legal guardian who can understand the participation of the study and voluntarily withdraw from the study at any time Exclusion Criteria: * Subjects who have difficulty swallowing tablet. * Subjects who have known allergy to plant extracts. * Subjects who meet DSM-IV diagnostic criteria for current major depressive disorder or anxiety disorder requiring drug therapy. * Subjects who have any history of bipolar disorder, psychotic disorder, and substance use disorder, have been diagnosed with a pervasive developmental disorder, organic brain disease and seizure disorder. * Subjects who have significant suicidal ideation. * Subjects with mental retardation * Subjects with Tourette's syndrome requiring drug therapy. * Subjects who have been administrated Methylphenidate or Atomoxetine within recent 3 months and Ginkgo extract or Ginseng extract within recent 1 month. * Subjects who currently have a significant medical conditions (e.g. diseases of cardiovascular, hepatic, renal, respiratory, glaucoma). * Subjects who have abnormalities in the ECG or show clinically significant abnormalities of laboratory results, including serum chemistries and hematology. * Subjects who are currently taking alpha-2 adrenergic receptor agonist, antidepressant, antipsychotic, benzodiazepines, modafinil,anticonvulsant * Subjects who receive psychosocial treatment during the drug trial. * Subjects who are not able to swallow the study drug.