Secondary evaluations of MTA 36-month outcomes: Propensity score and growth mixture model analyses

James M. Swanson, Stephen P. Hinshaw, L. Eugene Arnold, Robert D. Gibbons, Sue Marcus, Kwan Hur, Peter S. Jensen, Benedetto Vitiello, Howard B. Abikoff, Laurence L. Greenhill, Lily Hechtman, William E. Pelham, Karen C. Wells, C. Keith Conners, John S. March, Glen R. Elliott, Jeffery N. Epstein, Kimberly Hoagwood, Betsy Hoza, Brooke S.G. MolinaJeffrey H. Newcorn, Joanne B. Severe, Timothy Wigal

Research output: Contribution to journalArticlepeer-review

105 Scopus citations


OBJECTIVE: To evaluate two hypotheses: that self-selection bias contributed to lack of medication advantage at the 36-month assessment of the Multimodal Treatment Study of Children With ADHD (MTA) and that overall improvement over time obscured treatment effects in subgroups with different outcome trajectories. METHOD: Propensity score analyses, using baseline characteristics and severity of attention-deficit/hyperactivity disorder symptoms at follow-up, established five subgroups (quintiles) based on tendency to take medication at the 36-month assessment. Growth mixture model (GMM) analyses were performed to identify subgroups (classes) with different patterns of outcome over time. RESULTS: All five propensity subgroups showed initial advantage of medication that disappeared by the 36-month assessment. GMM analyses identified heterogeneity of trajectories over time and three classes: class 1 (34% of the MTA sample) with initial small improvement followed by gradual improvement that produced significant medication effects; class 2 (52%) with initial large improvement maintained for 3 years and overrepresentation of cases treated with the MTA Medication Algorithm; and class 3 (14%) with initial large improvement followed by deterioration. CONCLUSIONS: We failed to confirm the self-selection hypothesis. We found suggestive evidence of residual but not current benefits of assigned medication in class 2 and small current benefits of actual treatment with medication in class 1. Copyright 2007

Original languageEnglish (US)
Pages (from-to)1003-1014
Number of pages12
JournalJournal of the American Academy of Child and Adolescent Psychiatry
Issue number8
StatePublished - Aug 2007


  • Attention-deficit/hyperactivity disorder
  • Behavior therapy
  • Clinical trial
  • Multimodal treatment
  • Stimulant

ASJC Scopus subject areas

  • Developmental and Educational Psychology
  • Psychiatry and Mental health


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