Dexamphetamines associated with longer treatment persistence than methylphenidate in adult ADHD

A retrospective multicentre study published in Acta Psychiatrica Scandinavica compared stimulant treatment persistence over 12 months in 12,995 adults with ADHD, 49% of whom were female. The primary outcome, time-to-transition, measured the interval from treatment initiation to switching stimulant classes, transitioning to non-stimulants or complete discontinuation. Patients were censored at 12 months or their last clinical contact. Analyses used a multivariable mixed-effects Cox model accounting for clinician-level clustering.

Overall, 62% initiated dexamphetamines and 38% methylphenidate. Median time-to-transition was 33.1 weeks with dexamphetamines versus 15.0 weeks with methylphenidate. Methylphenidate was associated with a higher hazard of non-persistence (HR 1.45, 95% CI 1.36–1.55). Hyperactive/impulsive presentation (HR 1.14; p=0.025) and objectively measured impulsivity (HR 1.05; p=0.002) were independently associated with non-persistence. An interaction between stimulant class and objective hyperactivity suggested a greater persistence advantage for dexamphetamines with increasing motor activity (p=0.003).

These findings may inform discussions about treatment continuation in adult ADHD, but persistence is not a direct measure of symptom control or safety. The retrospective, non-randomised design leaves potential confounding and treatment-selection effects unresolved. Only the abstract was available, limiting assessment of adjustment variables and reasons for switching or discontinuation; the findings alone do not establish that prioritising dexamphetamines improves outcomes.