Stimulant Medication Use and Risk of Psychotic Experiences.

BACKGROUND AND OBJECTIVES The prescription of stimulant medications for young people with attention-deficit/hyperactivity disorder is common and increasing. Concerns have been raised about potentially psychotogenic effects of stimulants, and previous observational research has documented an increased risk of psychotic experiences in young people prescribed stimulants. Our aim was to estimate the causal effect of stimulants on psychotic experiences. METHODS The trial was emulated using Adolescent Brain Cognitive Development Study data. Eligible participants were aged between 9 and 14 years. Treatment (stimulant prescription) propensities were derived using covariates indexing demographic factors and mental illness severity. The average causal effect of first stimulant prescription on psychotic experiences by 1-year follow-up was derived using inverse probability of treatment weighting followed by standardization (doubly robust estimation). RESULTS Of 8391 participants included in the analytical sample, 460 (5.5%) reported 1 or more stimulant prescriptions. In unweighted analyses, stimulant prescription was associated with subsequent psychotic experiences (odds ratio [OR]: 1.46; 95% CI: 1.15-1.84). The reverse, however, was also true, in that baseline psychotic experiences predicted subsequent stimulant treatment (OR: 1.93; 95% CI: 1.57-2.37). When applying doubly robust estimation, there was no evidence of a causal effect of stimulant prescription on the subsequent occurrence of psychotic experiences (OR: 1.09; 95% CI: 0.71-1.56). CONCLUSIONS Our findings do not support a causal relationship between stimulant prescription and psychotic experiences. Rather, the association appears to be confounded by factors that both increase probability of stimulant prescription and lead to psychotic experiences.