Early Use of Methylphenidate: The Jury on Neuronal Effects Is Still Out

Little is known about the long-term effects of methylphenidate on the developing brain, despite the widespread and progressively increasing use of this stimulant drug, including among preschoolers (e.g., Journal Watch Psychiatry Apr 1 2000). Studies of methylphenidate’s effects on juvenile rats have shown varying results, highlighting the need for more research. These researchers exposed preadolescent rats to methylphenidate or saline for 16 days and then looked at neuronal development in the hippocampus as well as corticosterone levels and hippocampal neurogenesis after stress. Each test involved six exposed rats and six controls.

Contrary to the hypothesis, exposed and control rats did not differ in the proliferation of new cells in the su…