This study aimed to describe and compare the educational, social, and family profiles of adults with and without ADHD from two different settings: a prison and an outpatient psychiatric setting. A total of 542 participants, aged between 17 and 69 years, took part in the study. The participants consisted of four groups: a prison sample with ADHD (n = 69) and without ADHD (n = 183), and an outpatient psychiatric sample with ADHD (n = 218) and without ADHD (n = 72). The results showed that, firstly, there were some statistically significant differences between the groups in academic history, social and family situation, and the adoption of risk behaviors during adolescence and early adulthood. Secondly, some of these differences were related to diagnosis (ADHD versus non-ADHD) while others were related to the sample being examined (prison versus psychiatric). The findings from the study showed the presence of significant implications in social, family, educational, and employment achievements both for adults with ADHD (both prison and psychiatric samples) and for adults without ADHD.