Ritalin Use for ADHD Affects Adult Brain in Childhood

Attention deficit/hyperactivity disorder (ADHD) is characterized by symptoms of hyperactivity and difficulty with attention and control. The disease, which affects about 7.2% of the world's population, has a major influence on daily functions. Prevalence has increased dramatically over the past decade, affecting not only children but also adolescents and adults.

The main treatment for ADHD is the use of stimulants such as methylphenidate, more commonly known as Ritalin. Stimulants targeting dopamine in the brain have a good record to alleviate the symptoms of ADHD. The safety of Ritalin and other incentives have been widely studied, but the long-term effects remain unclear. This is especially important for patients with ADHD because the brain continues to develop during childhood and adolescence when the disorder is usually diagnosed.

GABA, or Υ-aminobutyric acid, is a neurotransmitter inhibitor involved in the pathophysiology of ADHD. The main problem in children with ADHD is inhibitory control, associated with GABA levels in the brain. Preclinical and clinical studies have shown that lower concentrations of GABA in a specific region of the brain called the prefrontal cortex in ADHD. This area of the brain is essential to inhibitory control and is also one of the last areas that are developing.


To assess the long-term effects of brain stimulating therapy, Solleveld and colleagues at the University of Amsterdam used brain scans to study GABA levels in adult patients with ADHD. The study, published in NeuroImage: Clinical, consisted of 44 men with ADHD between 23 and 40 years, divided into three groups. The first group was an early stimulant treatment group, made up of patients who had used stimulants before 16 years of age when the brain continues to develop. The other was a late stimulation group composed of patients who first used stimulants after 23 years when brain development is usually completed. The final group consisted of patients with ADHD who had never used stimulants. All participants reviewed a baseline analysis. Some participants also received oral administration of Ritalin 5 minutes after initial brain analysis followed by another 90 minutes later.
The researchers found that at the base before the administration of Ritalin, the stimulating group had started lower levels of GABA in the prefrontal cortex than the group in a stimulant, suggesting that the use of stimulants in childhood in a truly chemical way affects the brain of adulthood. In addition, only the initial stimulus group after Ritalin administration showed an increase in GABA levels.

Together, these findings show that lifelike stimulants when the brain is still developing may change brain chemistry, particularly the GABA system in the prefrontal cortex. The authors note: "The results of our study show that stimulants have different effects when it comes to developing mature brain." Additionally, further studies are needed to investigate the possible consequences of these inferior levels of GABA on cognitive and behavioral ADHD results.