The purpose of this study was to investigate whether individuals with ADHD followed-up to age 40 have a higher mortality, more involvement in criminal behavior, increased traffic accidents, and frequency or registered violations against traffic rules or whether they have been more frequently victims to crimes. The ADHD cohort (N=122) born in 1971-4 was isolated at the age of nine years from the base cohort of 865 children who had known risk factors at birth and were still alive at the age of five years. Ninety-four healthy individuals born during the same years served as control subjects. None of the ADHD individuals had used psychostimulants before their adolescence. The follow-up data were available from the newborn period until the ages of 5 and 9 years. At the ages of 16 and 30, the data were collected via questionnaire. For this study, the national police registers (last five years) were examined for traffic violations, crimes or being an object of a criminal act when the persons reached the age of 40 years. Ten ADHD men and one woman but none of the controls had died by the age of 40. Three died of disease related incidents, and eight (13%) died of abnormal causes such as suicides (3), traffic accidents (2), substance abuse (2), or violence (1). During the follow-up period, ADHD individuals had been involved in violent behavior or economic criminality more frequently than had the control subjects. They were also more commonly victims of criminal acts. No difference was found in traffic citations between ADHD and control subjects (at 35-40 yrs.) when all traffic crimes were considered. A difference was not observed in the frequency of traffic accidents. However, there was a significant difference in drunk driving (at the ages of 30 and 35-40) and the number of persons without a driver's license.