Scientists in the Netherlands have found evidence that stimulants used in the treatment of ADHD have different effects when acting on the developing or the mature brain. The study, published in the journal NeuroImage: Clinical, was the first to investigate the effects of childhood methylphenidate treatment on brain levels of the neurotransmitter GABA in adult ADHD patients. “The prevalence of ADHD has increased rapidly over the last few years,” said Michelle M. Solleveld of the