Amphetamines may cause serious adverse reactions, including psychosis. Many of the newer anorectic agents, such as diethylpropion, have similar psychotomimetic properties. These agents should be prescribed with caution in patients with a personal or family history of psychosis or a history of stimulant drug abuse, and patients should be informed of the risk of psychotic reaction. Prompt intervention, including psychiatric consultation, may be necessary when a psychotic reaction occurs.