The protective association appears only for childhood treatment, with no similar benefit seen when treatment begins in adolescence or adulthood.

Publication: JAMA Psychiatry.

A large Finnish study published in JAMA Psychiatry finds that treating children with ADHD using methylphenidate before age 13 does not raise the risk of psychotic disorders in adulthood and may even be linked to a reduced risk.

Researchers caution that the results may not apply to other ADHD medications like amphetamines (e.g., Adderall) and call for further studies on risks and adult-onset ADHD treatment differences.

Dr. Colm Healy of University College Dublin notes developmental differences across childhood, adolescence, and adulthood and urges urgent age-specific research as adult ADHD diagnoses rise.

Secondary analyses suggest the protective effect is specific to childhood-diagnosed cases and require more work to confirm and understand mechanisms, especially for adolescence and adulthood diagnoses.

Authors stress careful, evidence-based clinical assessment and say treatment decisions should consider potential short- and long-term benefits without undue anxiety, given the lack of increased long-term psychosis risk.

The article’s publication and main finding were highlighted by author Ian Kelleher as robust and reassuring.

Experts urge families and clinicians to take reassurance from the safety signal while supporting age-specific research amid rising adult ADHD diagnoses.

Experts say the findings should reassure parents, but stress ongoing monitoring and more research to understand age-specific effects and how different stimulant classes compare.

The methodology used instrumental variable analysis based on hospital district prescribing patterns to control for regional variation, analyzing birth cohorts from 1987 to 1997 (about 697,289 individuals).

The study, led by researchers from University College Dublin and University of Edinburgh and funded by the St John of God Research Foundation, was published in JAMA Psychiatry.