OBJECTIVES: ADHD is one of the most common mental disorders affecting children and adults. Past systematic reviews have provided estimates of ADHD associated costs but were limited to only the US and Europe. This study aims to systematically identify and summarize all global evidence on economic burden of ADHD.

METHODS: A systematic search for published studies on costs of ADHD was conducted in EconLit, EMBASE, PubMed, Cochrane Review, HEED, ERIC, PsycINFO, and MEDLINE. Additional literature was identified by searching the reference list of identified eligible studies. Quality of studies were assessed using Larg and Moss checklist.

RESULTS: 44 studies were included in this review. All studies were conducted in high-income countries and limited to the US and Europe except for three studies: two in Asia and one in Australia. Most studies were retrospective and undertook prevalence-based study design. 25% of the studies provided the national estimate whereas the rest provided per person estimates. In studies providing national estimates, average national costs of ADHD were 67.23 Billion USD. Adults incurred most of the burden when compared to children (67 Billion USD, 89.48% vs 7 Billion USD, 10.51%). Out of studies including children/adolescents, only 1 study captured both education (19 Billion USD, 76.02%) and healthcare cost (6.1 Billion USD, 23.97%). Similarly, for adults, only 1 study captured all components of ADHD cost: productivity and income losses (8.1 Billion USD, 80.38%), healthcare (1.3 Billion USD, 12.83%), and crime and traffic accidents (0.68 Billion USD, 6.78%).

CONCLUSIONS: The paucity of literature pertaining to cost of ADHD in low- or middle-income countries suggests lack of much needed research in order to better inform ADHD healthcare as well as policy making. This comprehensive review points to the large global economic burden of ADHD, multifaceted nature of ADHD costs and fragmented ADHD research across globe.