Deborah Mash

Midbrain dopamine (DA)-containing neurons have effects on a number of distinct behavioral functions, including sensorimotor integration, motivation and affect, and cognition. Disruption of normal DA cell function occurs in Parkinson’s disease, neuropsychiatric disorders, and psychostimulant dependence. Drugs of abuse and dependence, such as cocaine and amphetamines, act as psychostimulants in humans. Psychiatric complications of cocaine and amphetamine include paranoia, agitated delirium, delusional disorder, and the depressed mood and dysphoria associated with abrupt withdrawal. Amphetamine psychosis and cocaine arousal and reinforcement are presumed consequences of the stimulation of the mesolimbic DA pathway (for a review, see ref. 1).