Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental alteration of biological basis that started in childhood may persist during adolescence-youth and, despite what was believed until not many years ago, also in adulthood up to 50-60% of those affected, producing a significant clinical and psychosocial deterioration. In spite of being a syndrome easily identifiable by the triad: inattention, hyperactivity and impulsivity that characterizes it, in clinical practice there are different circumstances that hinder and complicate its diagnosis and treatment. One of the most significant is the presence, both in childhood and adulthood, of other comorbid mental disorders. It is from adolescence-youth when together with ADHD we can detect the presence of personality, mood and anxiety disorders and especially the use of several substances. The evidences existing until now show how the comorbidity of ADHD and substance use disorder influence the evolutionary course of both, complicating the approach, the treatment and, therefore, aggravating the final prognosis. The difficulties in their approach and the scarcity of treatment options make us underline the importance of preventive treatment in the infantile stage, starting from psychoeducation programs focused on the vulnerability of these patients to substances and the consequences associated with consumption.