An Efficacy and Safety Study of Osmotic Release Oral System (OROS) Methylphenidate in Participants With Attention Deficit Hyperactivity Disorder (ADHD)

The purpose of this study is to evaluate the safety and efficacy of Osmotic Release Oral System (OROS) methylphenidate in participants with Attention Deficit Hyperactivity Disorder (ADHD).

This is an open-label (all people involved know the identity of the intervention), single arm, multicenter (when more than one hospital or medical school team work on a medical research study), prospective study (study following participants forward in time) to evaluate the efficacy and safety of OROS methylphenidate in participants with ADHD (behavior disorder originating in childhood in which the essential features are signs of developmentally inappropriate inattention, impulsivity, and hyperactivity). The study duration will be of 12 weeks per participant, which is divided into 2 parts Screening (within 14 days before study commences on Day -1) and treatment (8 weeks and will include titration period \[from the initiation of the study treatment to determination of the individual's maintenance dose\] and maintenance period \[at least 4 weeks after determination of maintenance dose\]). Participants will receive initial dose depending on their body weight. OROS methylphenidate hydrochloride (HCL) will be given orally once daily at an initial dose of 18 milligram (mg) for participants below 30 kilogram (kg) and 27 mg for those over 30 kg of body weight. The dose will be increased by 9 mg or 18 mg every week for up to Week 8, followed by a maximum maintenance dose of 54 mg orally once daily up to Week 12 during which the dose can be decreased by 9 mg depending on tolerability. Efficacy will be evaluated by Korean Version, ADHD Rating Scale (K-ARS) total score and Clinical Global Impression)-Severity / Impression rating scale CGI-S/I. Participants safety will be monitored throughout the trial.

Eligibility Criteria:
Inclusion Criteria:

* Participants voluntarily provided informed consent to participate in the study
* Participants with written informed consent to participate in the study voluntarily by caregivers/legal representatives
* Participants who were capable to follow the study visit schedule well and their parents/caregivers who were willing to complete the assessments specified in the protocol and were capable to complete them
* Participant and his/her parent/guardian able to understand the study participation and to request withdrawal from the study voluntarily at any time
* Participants who were satisfied in diagnosis of Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) Attention Deficit Hyperactivity Disorder (ADHD) and determined to require drug therapy

Exclusion Criteria:

* Participants who have known hypersensitivity (altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen) to methylphenidate HCL
* Participants who have significant suicidal ideation
* Participants with mental retardation
* Participants who meet DSM-IV diagnostic criteria for current major depressive disorder or anxiety disorder requiring drug therapy
* Participants who have abnormalities in the Electrocardiography (ECG) or show clinically significant abnormalities of laboratory results, including serum chemistries and hematology