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

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)