His Neglect research extends to the thematically linked field of Psychiatry. His study connects Psychiatry and Neglect. His research ties Attention deficit hyperactivity disorder and Clinical psychology together. Much of his study explores Attention deficit hyperactivity disorder relationship to Clinical psychology. His Young adult study typically links adjacent topics like Gerontology. Gerontology is closely attributed to Young adult in his study. His Combinatorics study typically links adjacent topics like Comparability. His study ties his expertise on Combinatorics together with the subject of Comparability. His Internal medicine study frequently links to adjacent areas such as Epidemiology.

His most cited work include:
Childhood adversities and adult psychopathology in the WHO World Mental Health Surveys (1486 citations)
Cross-national prevalence and correlates of adult attention-deficit hyperactivity disorder (1144 citations)