Ritalin and Depression
December 10, 2003
Ritalin use in preteen children may lead to depression later in life, studies of rats suggest.
It is an open question whether what passes for depression in lab rats has anything to do with depression in humans. But early use of Ritalin and other stimulant drugs seems to permanently alter animals' brains. That raises concerns that the same thing might be happening in children who take these drugs for attention deficit hyperactivity disorder (ADHD).
The findings come from a research team led by William A. Carlezon Jr., director of the behavioral genetics laboratory at McLean Hospital and associate professor at Harvard Medical School.
According to Carlezon:
- Rats exposed to Ritalin as juveniles showed large increases in learned-helplessness behavior during adulthood, suggesting a tendency toward depression.
- These rats also showed abnormally high levels of activity in familiar environments.
- This might reflect basic alterations in the way rats pay attention to their surroundings.
Ritalin and cocaine have different effects on humans. But their effects on the brain are very similar. When given to preteen rats, both drugs cause long-term changes in behavior.
One of the changes seems good: Early exposure to Ritalin makes rats less responsive to the rewarding effects of cocaine. But that's not all good. It might mean that the drug short-circuits the brain's reward system. That would make it difficult to experience pleasure -- a "hallmark symptom of depression," Carlezon notes.
The other change seems all bad. Early exposure to Ritalin increases rats' depressive-like responses in a stress test.
These experiments suggest that preadolescent exposure to [Ritalin] in rats causes numerous complex behavioral adaptations, each of which endures into adulthood, Carlezon concludes.
Source: Daniel DeNoon, "Preteen Ritalin May Increase Depression: Early Use of ADHD Drug Alters Brain, Rat Studies Show," WebMD, December 8, 2003; based upon, W.A. Carlezon Jr., Biological Psychiatry, Vol. 54: pp 1330-1337, Dec. 15, 2003.
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