Literature Review: Update on Amphetamine Neurotoxicity and Its Relevance to the Treatment of ADHD

Abstract

Objective: A review of amphetamine treatment for attention-deficit/hyperactivity disorder (ADHD) was conducted, to obtain information on the long-term neurological consequences of this therapy. Method: Several databases were accessed for research articles on the effects of amphetamine in the brain of laboratory animals and ADHD diagnosed individuals. Results: In early studies, high doses of amphetamine, comparable to amounts used by addicts, were shown to damage dopaminergic pathways. More recent studies, using therapeutic regimens, appear contradictory. One paradigm shows significant decreases in striatal dopamine and transporter density after oral administration of “therapeutic” doses in primates. Another shows morphological evidence of “trophic” dendritic growth in the brains of adult and juvenile rats given systemic injections mimicking “therapeutic” treatment. Imaging studies of ADHD-diagnosed individuals show an increase in striatal dopamine transporter availability that may be reduced by methylphenidate treatment. Conclusion: Clarification of the neurological consequences of chronic AMPH treatment for ADHD is needed. (J. of Att. Dis. 2007; 11(1) 8-16)