Study to Evaluate the Efficacy and Quality of Life of Long-Acting Methylphenidate in Adults With Attention Deficit Hyperactivity Disorder (ADHD)

The purpose of this study is to evaluate the efficacy, safety and to assess the impact of the treatment on quality of life of long-acting methylphenidate in adult participants with Attention Deficit Hyperactivity Disorder (ADHD). ADHD is a clinical condition beginning in childhood and is characterized by inadequate levels of attention, hyperactivity and impulsiveness.

This is an open-label (all people know the identity of the intervention), multi-center (when more than one hospital or medical school team work on a medical research study), single arm study of multiple doses of long-acting methylphenidate in participants with ADHD. The study will consist of 2 phases; a screening phase and a treatment phase. The duration of participation in the study for an individual participant will be up to 12 weeks. Participants will be given 18 milligram (mg) of long-acting methylphenidate daily in the morning and titrated up (slow increase in drug dosage guided by participant's responses) to 36 mg per day (mg/day) on Day 8. Depending on response, tolerability and clinician's judgment, the dose could be escalated to the next dose level of 54 mg/day on Day 28 to a maximum of 72 mg/day on Day 56, until each participant achieved optimal dose. Participant's safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria

* Diagnosis of Attention Deficient Hyperactivity Disorder (ADHD) according to the Diagnostic and Statistical Manual of Mental Diseases, Fourth Edition (DSM-IV), obtained via interview with an adapted version of the Kiddie-Schedule of Affective Disorders and Schizophrenia-Epidemiologic Version (K-SADS E) module for ADHD
* Described chronic course of ADHD symptomatology from childhood to adulthood, with some symptoms present before age 7 years, which continue to meet DSM-IV criteria at the time of assessment. ADHD is not diagnosed if the symptoms are better accounted for by another psychiatric disorder \[e.g. mood disorder (especially bipolar disorder), anxiety disorder, psychotic disorder, personality disorder\]
* Clinical Global Impression-Severity (CGI-Severity) baseline score greater than or equal to (\>=) 4 (at least moderate severity)
* Female participants must be postmenopausal (after the time in life when a woman stops having a menstrual period) for at least 1year, surgically sterile, or practicing an effective method of birth control (e.g., prescription oral contraceptives\[compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy\], contraceptive injections \[chemical substances that prevent or reduce the probability of pregnancy\], intrauterine device \[contraceptive devices placed high in the uterine fundus\], double-barrier method, contraceptive patch, male partner sterilization) before entry and throughout the study; have a negative urine pregnancy test at baseline
* Participant agrees to take only the supplied study drug as treatment for ADHD during the study

Exclusion Criteria

* Participant having allergy or hypersensitivity to methylphenidate
* Participants who are non-responder to methylphenidate in adequate doses (i.e., 0.8 - 1.0 milligram per kilogram \[mg/kg\])
* Participant treated with any methylphenidate or amphetamine containing medication within 4 weeks of the screening visit
* Participant having Hamilton's Depression Scale, suicide item higher than 2
* Participant having any psychiatric condition including the following, but not limited to: acute mood disorder (disorders that have a disturbance in mood as their main feature), schizophrenia (a mixed psychiatric disorder relating to a complex psychotic state that has features of both schizophrenia and a mood disorder such as bipolar disorder), bipolar disorder I (disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission \[when a medical problem gets better or goes away at least for a while\] and recurrence \[happen again\]), obsessive compulsive disorder (OCD) (an anxiety disorder characterized by recurrent, persistent obsessions or compulsions, anti-social personality disorder ( personality disorder whose essential feature is a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood or early adolescence and continues into adulthood)