Childhood ADHD treatment may reduce the risk of psychosis later in life, study shows

A new large-scale study shows that a widely used medication for treating attention deficit hyperactivity disorder (ADHD) in childhood not only does not increase the long-term risk of psychosis but may even reduce it. This was reported by Euronews.

The study, led by researchers from University College Dublin and the University of Edinburgh, provides some of the clearest evidence to date that stimulant medications do not increase the risk of serious psychotic disorders such as schizophrenia.

ADHD is one of the most common mental health disorders, affecting approximately 8% of children and adolescents. Globally, about 366 million adults live with the condition, with symptoms including difficulty concentrating, hyperactivity, and impulsivity.

The study, published in the journal JAMA Psychiatry, analyzed health data from nearly 700,000 people born in Finland, including almost 4,000 individuals diagnosed with ADHD.

Researchers found no evidence that treatment with methylphenidate—the most commonly prescribed medication for ADHD in children—increases the likelihood of developing psychotic disorders in adulthood.

“We know that when children with ADHD are followed into adulthood, a small but significant proportion of them develop psychotic disorders such as schizophrenia,” says Prof. Ian Kelleher, Professor of Child and Adolescent Psychiatry at the University of Edinburgh and lead author of the study.

“The key question was whether ADHD medications cause this risk, or if it is a situation where correlation does not imply causation. Our results show that the treatment itself is not the factor leading to this risk,” he explains.

The question has been essential in psychiatric research for years, especially considering that stimulants affect dopamine—a brain chemical also linked to psychosis.

“A number of studies show that a small but significant proportion of children with ADHD later develop psychotic disorders—in our study, this was about 6%,” Kelleher told Euronews Health.

“This raised concerns that ADHD medications might be contributing to this risk, especially given that stimulants increase dopamine activity—a substance that also plays a role in psychosis,” he adds.

While the primary finding is the lack of increased risk, researchers also discovered a possible additional benefit: children treated with methylphenidate before the age of 13 showed a slightly lower risk of developing psychosis later in life.

“The fact that early treatment is associated with a lower long-term risk of psychosis suggests that these medications may have effects beyond simply controlling childhood symptoms—it is possible they also have a protective effect against severe mental illness, though this requires further research,” says Kelleher.

He adds that the results are “reassuring for doctors and patients, as well as for families considering treatment,” and that “at standard therapeutic doses, methylphenidate does not appear to increase the risk of psychosis.”

However, the study results specifically pertain to methylphenidate and to children and adolescents.

“We were only able to analyze methylphenidate,” says Kelleher.

“However, we were unable to examine another major group of stimulants used to treat ADHD—amphetamines. Therefore, we cannot draw conclusions regarding the risk of psychosis with medications of that type,” he added to Euronews Health.

The study also did not look at the growing number of adults diagnosed with ADHD.

“As the number of adults being diagnosed and treated for ADHD increases, it is unclear whether our results would also apply to them,” Kelleher points out.

“Further research is also needed to understand why the risk of psychosis is higher in children with ADHD, even though this increase is not explained by methylphenidate treatment,” he adds.