Methylphenidate has become the drug of choice since it is mainly prescribed for children and adults who suffer from ADHD. A psychomotor stimulant that is sold under the trade name 'Ritalin'. ADHD is one of the most common chronic childhood onset psychiatric disorders that can persist into adulthood. The effectiveness of MPH has been confirmed among children and adults who suffer from ADHD, yet the mechanism of its action is poorly understood. It is agreed by literature that these drugs produce their effects by blocking dopamine reuptake through the dopamine transporter or by inducing dopamine transporter-mediated reverse transport that causes increase in dopamine (DA) and norepinephrine (NE) concentration in central nervous system.