Can chronic use of therapeutic doses of Adderall, Vyvanse, or Dexedrine (amphetamines) cause brain damage?
The bottom line is we don't know. However there is a body of research that raises some concerns but gives no strong conclusive evidence either way. A comprehensive review article was published in February of 2009 "Literature Review: Update on Amphetamine Neurotoxicity and Its Relevance to the Treatment of ADHD" and is available free (1).
A worrisome study in monkeys in 2005 by Ricaurte found some evidence suggesting dopamine nerve damage in areas of the brain involved in ADHD dysregulation and amphetamine therapeutic effects (2). Some of the monkeys were given doses that are normally given to humans. However, multiple similar studies in rodents did not find evidence of this damage in usual dosage ranges that are given to humans. In contrast to amphetamines, high dose methylphenidate (Ritalin, Concerta, Focalin, Daytrana) studies appeared to have lower risk for brain toxic effects (3, 4).
Stimulant treatment of ADHD during childhood appears to reduce the risk of substance abuse that is otherwise associated with ADHD.(5, 6) Also children with ADHD who had not been treated with stimulants have smaller brain white matter volume than children with ADHD who had been medicated or children without ADHD. Stimulant treatment in children may actually increase brain growth and development.(7) However, older rodents, when given methamphetamine in doses that are known to be toxic to younger rodents and humans, had more toxic brain reactions than younger rodents. They also had brain levels of amphetamine that was twice as high as the levels in younger rodents when given the same dose. Natural aging processes reduce dopamine production greatly. Older humans may be at greater risk of toxic effects of amphetamine
No controlled studies have examined the adverse behavioral, cognitive, neurophysiological effects of years, much less decades, of chronic amphetamine treatment. Neuroimaging with PET and MRI techniques are becoming increasingly useful in measuring brain anatomy and function in living human beings to explore for brain damage in humans treated with amphetamine. We look forward to the coming evidence to make more informed treatment recommendations to our patients with ADHD.
1.(Free) Literature Review: Update on Amphetamine Neurotoxicity and Its Relevance to the Treatment of ADHD
