Attention-Deficit/Hyperactivity Disorder (ADHD) is a chronic neurodevelopmental disorder that is characterized by attentional problems, deficient impulse control, hyperactivity and often also by emotional dysregulation. ADHD has its onset in childhood and affects approximately 5% of children. In over half of the individuals with ADHD, symptoms persist into adulthood and even old age. World-wide, ADHD in adulthood is under-recognised and under-treated. Undiagnosed or untreated ADHD in adulthood is problematic, because it often co-occurs with other psychiatric and somatic illnesses. Among the most prevalent ones are major depression, anxiety, substance use and obesity. These comorbid conditions considerably contribute to the disease burden of individuals, as well as to healthcare costs. In many instances, individuals with ADHD drop out of psychiatric healthcare in the transition from childhood to adult services. Later in life, they often return with symptoms of comorbid conditions; their ADHD often is not recognised at that point and there is a danger that they might receive treatments for their comorbid problems without awareness and adequate care for the underlying ADHD. Providing care throughout the lifespan, but especially in young adults, may therefore be pivotal to reducing this negative developmental trajectory later in life. In this course, experts in adult ADHD will inform clinical psychiatrists about the prevalence and characteristics of ADHD in adulthood and its most common comorbid conditions across the lifespan. Using real life examples of cases, participants will practice how to diagnose ADHD in the context of comorbidity, and discuss different (pharmacological and non-pharmacological) treatment and psychotherapy options.