Attention Deficit Disorder with Hyperactivity: A behavior disorder originating in childhood in which the essential features are signs of developmentally inappropriate inattention, impulsivity, and hyperactivity. Although most individuals have symptoms of both inattention and hyperactivity-impulsivity, one or the other pattern may be predominant. The disorder is more frequent in males than females. Onset is in childhood. Symptoms often attenuate during late adolescence although a minority experience the full complement of symptoms into mid-adulthood. (From DSM-V)Methylphenidate: A central nervous system stimulant used most commonly in the treatment of ATTENTION DEFICIT DISORDER in children and for NARCOLEPSY. Its mechanisms appear to be similar to those of DEXTROAMPHETAMINE. The d-isomer of this drug is referred to as DEXMETHYLPHENIDATE HYDROCHLORIDE.Learning Disorders: Conditions characterized by a significant discrepancy between an individual's perceived level of intellect and their ability to acquire new language and other cognitive skills. These disorders may result from organic or psychological conditions. Relatively common subtypes include DYSLEXIA, DYSCALCULIA, and DYSGRAPHIA.Central Nervous System Stimulants: A loosely defined group of drugs that tend to increase behavioral alertness, agitation, or excitation. They work by a variety of mechanisms, but usually not by direct excitation of neurons. The many drugs that have such actions as side effects to their main therapeutic use are not included here.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Hyperkinesis: Excessive movement of muscles of the body as a whole, which may be associated with organic or psychological disorders.Attention Deficit and Disruptive Behavior Disorders: Includes two similar disorders: oppositional defiant disorder and CONDUCT DISORDERS. Symptoms occurring in children with these disorders include: defiance of authority figures, angry outbursts, and other antisocial behaviors.PropylaminesReceptors, Dopamine D4: A subtype of dopamine D2 receptors that has high affinity for the antipsychotic CLOZAPINE.Bipolar Disorder: A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Diagnostic and Statistical Manual of Mental Disorders: Categorical classification of MENTAL DISORDERS based on criteria sets with defining features. It is produced by the American Psychiatric Association. (DSM-IV, page xxii)Mental Disorders: Psychiatric illness or diseases manifested by breakdowns in the adaptational process expressed primarily as abnormalities of thought, feeling, and behavior producing either distress or impairment of function.Conduct Disorder: A repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate societal norms or rules are violated. These behaviors include aggressive conduct that causes or threatens physical harm to other people or animals, nonaggressive conduct that causes property loss or damage, deceitfulness or theft, and serious violations of rules. The onset is before age 18. (From DSM-IV, 1994)Impulsive Behavior: An act performed without delay, reflection, voluntary direction or obvious control in response to a stimulus.Adrenergic Uptake Inhibitors: Drugs that block the transport of adrenergic transmitters into axon terminals or into storage vesicles within terminals. The tricyclic antidepressants (ANTIDEPRESSIVE AGENTS, TRICYCLIC) and amphetamines are among the therapeutically important drugs that may act via inhibition of adrenergic transport. Many of these drugs also block transport of serotonin.Dextroamphetamine: The d-form of AMPHETAMINE. It is a central nervous system stimulant and a sympathomimetic. It has also been used in the treatment of narcolepsy and of attention deficit disorders and hyperactivity in children. Dextroamphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulating release of monamines, and inhibiting monoamine oxidase. It is also a drug of abuse and a psychotomimetic.