The objective is to highlight the clinical and social outcomes among adults who suffered from Attention-Deficit Hyperactivity Disorder (ADHD) in their childhood/adolescence. PubMed, PsycINFO, and Scopus databases were searched for prospective studies published during the last 5 years addressing patients with ADHD in childhood/adolescence followed-up to adulthood. We also included studies published before 2015 reported in other reviews with similar outcomes. Thousand four-hundred and eighty-five studies were identified, but only 39 were included for qualitative analysis and 27 for quantitative analysis. Overall, we found that ADHD persisted into adulthood with a mean rate of 43% and was mainly associated with both substance/alcohol use disorders and antisocial behavior and, less frequently, with anxiety and depressive disorders. The prevalence of persistent ADHD in adulthood reported by studies published after 2011 (55%) was higher than that reported by studies published previously from 1985 to 2011 (34%), suggesting a greater focus on ADHD in recent years. Our results highlight that ADHD can be considered not only a neurodevelopmental disorder, but also a persistent and complex condition, with detrimental consequences for quality of life in adulthood.