Attention-deficit/hyperactivity disorder: clinical phenotypes, polymorphism of life-course manifestations, and therapeutic strategies

Attention-deficit/hyperactivity disorder (ADHD) is a common neurobehavioral disorder that manifests in childhood and persists into adulthood. The prevalence of ADHD (USA/worldwide) in children and adolescents is 9.5/5.29 %, in adults — 4.4/2.5 %. The disorder has strong genetic correlations with numerous mental disorders and neurological diseases, in particular with post-traumatic stress disorder, addiction to cannabis, cocaine, recurrent and bipolar affective disorders, behavioral disorders, which is the biological basis of its clinical polymorbidity. Symptoms of ADHD overlap with other clinical manifestations of neurodevelopmental disorders (symptoms of autistic spectrum disorders, speech disorders, movement disorders, dyslexia, cognitive impairment), forming a polymorphic spectrum of pervasive developmental variants. Psychostimulants have been the standard of ADHD treatment for over 50 years. In 2002, atomoxetine became the first nonstimulant medication approved by the Food and Drug Administration for the treatment of ADHD, first in children and later in adult patients. Stimulant and nonstimulant medications have been shown to be effective in different phenotypes of ADHD (comorbidity with other mental and neurological disorders). In case of comorbidity of ADHD with anxiety, tics, atomoxetine has an advantage over stimulants and, together with alpha-2-adrenergic receptor agonists, can be recommended as the first drug. The presence of comorbid anxiety disorder or recurrent depression does not impact the efficacy and side effects of atomoxetine. Thus, atomoxetine is an effective drug and not only improves the symptoms of ADHD, but also plays a certain role in the treatment of patients with comorbid depression and anxiety.