Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with underlying brain anatomical and functional measures, as well as familial/genetic factors that are major foci of neuropsychiatric research. In recent years, ADHD is one of the neuropsychiatric diseases receiving more attention in scientific literature. During this decade, numerous studies were published on the implementation of diagnostic criteria and assessment tools for clinical research and the social impact of the disease, which continued to discuss genetic and neurobiological aspects. Psychostimulants are highly effective medications for the treatment of ADHD, and the development of long-acting stimulant formulations has greatly expanded the treatment options for individuals with ADHD. However, despite the established efficacy of the stimulants in ADHD, 10-30% of the adolescent population with ADHD does not respond to stimulants or may not tolerate them due to side effects. The potential for abuse and the stigma of a controlled medication are reasons to consider alternatives to stimulants in children and adolescents with ADHD. Traditionally, ADHD is regarded as a childhood disorder, but it is now clear that ADHD affects both children and adults. Many adults with ADHD are undiagnosed and untreated. Thus, the negative outcomes reported by most follow-up studies may be a consequence of untreated symptoms. The diagnosis of ADHD is broad and heterogeneous, with multiple causes being of neurological, paediatric and psycho-social nature. With this in mind, it must always be done rigorously by a multidisciplinary team.