Advances in the Neurobiology of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a lifelong condition that begins in childhood and continues with adult manifestations related to the core symptoms. Approximately 50% to 75% of children with ADHD continue to meet criteria for the disorder as adolescents and adults. Adults with the disorder increasingly present to primary care physicians, psychiatrists, and other practitioners for diagnosis and treatment. Understanding the diagnosis of ADHD in adults requires knowledge of age-dependent decline of symptoms over time. Retrospective recall of symptoms and impairment are valid methods of diagnosing the disorder. ADHD is also a brain disorder with a strong neurobiologic basis, complex etiology, and genetic component. Genetic and environmental vulnerabilities give rise to abnormalities in the brain and subsequent behavioral and cognitive deficits, which may produce the symptoms associated with ADHD. Magnetic resonance imaging studies of ADHD have provided evidence that abnormalities in the brain are caused by the disorder itself rather than treatment of the disorder. Psychiatric comorbidity is common among patients with ADHD and tends to complicate treatment. Acute and long-term use of long-acting stimulant formulations (methylphenidate and amphetamine compounds) have shown robust efficacy and tolerability consistent with the treatment response established in children with ADHD. Non-stimulant medications have demonstrated efficacy as well, and may be preferred in patients with tic and substance use disorders.In this expert roundtable supplement, Timothy E. Wilens, MD, reviews the epidemiology and clinical presentation of adult ADHD. Next, Joseph Biederman, MD, provides an overview of recent advances in the neurobiology of ADHD. Thomas J. Spencer, MD, reviews stimulant treatment of adult ADHD, and Lenard A. Adler concludes with a discussion of non-stimulant trials in adult ADHD.