Below we provide the report results, including the Key Points for each Key Question (KQ), and describe the included evidence, as well as the data synthesis and a summary of the strength of evidence. Details on results of literature searches, included studies, and the strength of evidence can be found in Appendixes A, C. D, and E. The list of excluded studies can be found in Appendix B.

The searches Identified 23,139 citations. Of these, we obtained 7,534 as full text. The flow diagram (Figure 2) describes the study flow through the literature review.

Figure 2

Flow diagram. Notes: KQ = Key Question

In total, 550 studies reported in 1,097 publications met the eligibility criteria.^{18, 21, 24, 27, 28, 56, 104–1194} This included 231 studies addressing KQ1, 312 studies addressing KQ2, and 10 studies addressing KQ3 (three studies contributed to more than one review question). Appendix E includes a list of included studies. Throughout the report, included studies are listed by the study ID which is composed of the first author’s last name of a key publication reporting on the study and the publication year of the key publication. The evidence table in the appendix shows the study ID and cites the main publication selected for the study and all multiple publications providing additional input on the study.

The flow diagram summarizes the main reason for exclusion from the review. In addition, it shows that we retained a large number of papers as background. The list of excluded studies and background studies is listed in Appendix B. In most cases, these were existing systematic reviews addressing an individual aspect of attention deficit hyperactivity disorder (ADHD) research that were then reference-mined to ensure that all eligible studies had been included in the report.

Studies included different age ranges. Figure 3 plots the mean age for each study.

Figure 3

Mean age across studies.

The median minimum age in included studies was 6 years old.

The number of included girls was low. Figure 4 plots the proportion of female participants across the research studies.

Figure 4

Proportion of female participants across studies.

The median number of girls included in the studies was 25 percent.

The following subchapters address each Key Question: Chapter 4 presents the results on diagnosing ADHD, Chapter 5 presents the results on treating ADHD, and Chapter 6 presents the results of approaches to monitoring ADHD.