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Evidence / 2019

observational

Psychosis with Methylphenidate or Amphetamine in Patients with ADHD

Moran LV, Ongur D, Hsu J, Castro VM, Perlis RH, Schneeweiss S (2019). New England Journal of Medicine.

Population
Adolescents and young adults (13–25) newly prescribed a stimulant for ADHD, US insurance claims
Sample
337,919 people in two US claims databases; matched new-user comparison
Condition
ADHD; incident psychosis defined by diagnosis plus antipsychotic prescription
Medication focus
Amphetamine versus methylphenidate
Jurisdiction
United States
Last reviewed
1 September 2026
PMID
30893533
DOI
10.1056/NEJMoa1813751

Plain-language finding

In a new-user observational comparison, amphetamine use was associated with a greater risk of a subsequent psychosis episode than methylphenidate. Psychosis events were uncommon in both groups (reported as 0.21% versus 0.10% in the paper’s primary comparison).

Important limitation

Observational claims data cannot prove causation. Residual confounding, diagnostic coding, and US prescribing patterns limit generalisation. The outcome definition required both a psychosis diagnosis and an antipsychotic prescription. Uncommon events in large samples still matter clinically for the people who experience them.

Why we cite this

The most widely cited comparative observational study of stimulant class and incident psychosis in ADHD treatment.

adhd · amphetamine · methylphenidate · psychosis · observational

Research demonstrates a statistical relationship. Association is not causation. Timing, dose, confounding and missing data still matter.

Claims this source supports

  • Prescription amphetamine treatment has been associated with an uncommon increased occurrence of psychotic symptoms compared with methylphenidate in a large observational study of young people. The events were uncommon in both groups. Association is not proof that amphetamine caused psychosis in any individual.

    Last reviewed 1 September 2026