No link between methylphenidate use and psychosis risk among children with ADHD

The use of methylphenidate in the treatment of children with attention-deficit/hyperactivity disorder (ADHD) does not contribute to an increased risk of nonaffective psychosis and may even confer protection against the risk, according to a study.

Researchers used data from multiple national Finnish registries and identified childhood and adolescent ADHD diagnoses (age <18 years) from 2003 onwards. They evaluated the cumulative amount of methylphenidate exposure in four intervention windows: within 1, 2, 3, and 4 years after ADHD diagnosis. The primary outcome was a diagnosis of nonaffective psychotic disorder by the end of follow-up in 2016.

A total of 3,956 individuals diagnosed with ADHD (median age 14.16 years, 80.4 percent male), of which 2,728 (69 percent) received methylphenidate at least once. Nonaffective psychosis was diagnosed in 222 individuals (5.7 percent) by mean age of 22.16 years.

Instrumental variable analysis indicated no significant association between sustained treatment with methylphenidate (30 mg/d) and the risk of nonaffective psychosis in the overall ADHD sample (1-year risk difference [RD], −0.14, 95 percent confidence interval [CI], −0.85 to 0.42; 4-year RD, −0.15, 95 percent CI, −0.49 to 0.11).

However, secondary analyses showed evidence of a reduced risk of nonaffective psychosis with methylphenidate treatment among individuals diagnosed in childhood (age <13 years: 3-year RD, –0.24, 95 percent CI, –0.45 to –0.03; p=0.03; 4-year RD, –0.21, 95 percent CI, –0.48 to –0.07; p=0.02).