Purpose: To systematically identify and review the currently available evidence on the long-term outcomes of recommended attention-deficit hyperactivity disorder (ADHD) interventions following randomized controlled trials with children and young people.
Method: A systematic search was conducted to identify trials >1 year in length using the following databases: CINAHL (January 1982- July 2012), MEDLINE (Ovid and Cambridge Scientific Abstracts [CSA]), Psych info, Science Direct (Elsevier), and Cochrane Library. Hand searches of key journals in the subject, book chapters, and conference proceedings were also carried out. Relevant papers were critically appraised using the Cochrane risk of bias tool.
Results: Eight controlled trials were identified as being relevant, of duration ranging from 1 year to 8 years (at follow up). The total number of participants in the studies was 1,057, of whom 579 (54.7%) were from one cohort and included 26 different outcome measures. Results suggest there is moderate-to-high-level evidence that combined pharmacological and behavioral interventions, and pharmacological interventions alone can be effective in managing the core ADHD symptoms and academic performance at 14 months. However, the effect size may decrease beyond this period.
Conclusion: This review has highlighted the paucity and limitations of the evidence investigating the long-term outcomes of recommended interventions for managing ADHD symptoms. There is little evidence to suggest that the effects observed over the relatively short term are maintained throughout longer periods of impairment. Furthermore, much of the existing evidence examining effectiveness beyond 12 months does not include newer medications currently available or consider significant contextual and cultural differences, such as UK/European and Asian populations. Longitudinal studies are required to examine the long-term outcomes for children and young people with ADHD managed with currently recommended service interventions. They should also include the whole spectrum of ADHD, with its full range of coexisting conditions, and cultural and contextual diversity.
Keywords: ADHD; multimodal intervention; pharmacological intervention.