After a decade on stimulants, the brain bounces back
STUDY: Zhang X et al, Neurotoxicology and Teratology 2023;97:107173
STUDY TYPE: Controlled animal study
FUNDING: National Center for Toxicological Research / U.S. Food and Drug Administration
Background
Many patients with ADHD take methylphenidate for years or decades, and some will eventually stop. Whether long-term use leaves a lasting neurochemical footprint has not been well tested until this trial, conducted in primates.
The Study
- 18 adult male rhesus monkeys received either placebo or methylphenidate (normal or high doses) five days a week for 12 years, starting in adolescence.
- Six months after stopping, researchers used PET imaging to measure brain glucose metabolism, dopamine transporter density, and dopamine receptor availability in the striatum and other regions.
Six months after cessation, no significant differences were found between treated and control animals in brain glucose metabolism, dopamine transporter (VMAT2) density, or dopamine D2 receptor availability. Even the high-dose group (5 to 10 times the human clinical equivalent) showed no lasting neurochemical changes.
Limitations: Animal data, small samples.
Practice Implications
- This is encouraging news for people with ADHD who take long term stimulants.
- Other animal studies have shown brain toxicity with high dose stimulants, but most of these involved amphetamines. Methylphenidate is generally safer all around.
— Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
