Attention Deficit Hyperactivity Disorder: Causes

Attention Deficit Hyperactivity Disorder - Causes

The causes of attention deficit hyperactivity remain unknown. Similar clinical manifestations are found in the syndrome of fragile X chromosome, alcoholic fetal syndrome, in children born with very low weight, and also with very rare hereditary thyroid diseases; but these conditions are revealed only in a small part of cases of attention deficit hyperactivity disorder. The search for the causes of attention deficit hyperactivity are conducted in different directions with the help of genetic, neurochemical studies, methods of structural and functional neuroimaging, etc. For example, in patients with attention deficit hyperactivity, the size of the anterior parts of the corpus callosum has decreased. Single-photon emission computed tomography (SPECT) revealed focal hypoperfusion in the striatum zone and hyperperfusion in the sensory and sensorimotor cortex areas. Genealogical studies conducted over the past 25 years have shown that attention deficit hyperactivity and comorbid conditions with it tend to accumulate in certain families, and the probability of inheritance of attention deficit hyperactivity varies from 0.55 to 0.92. A number of studies have shown a decrease in the circulation of dopamine and norepinephrine in the brain, but neurochemical processes in the brain are extremely complex, and attempts to link the development of attention deficit hyperactivity with the dysfunction of any one neurotransmitter system seem to be an obvious simplification. Psychosocial and external factors (for example, nutritional supplements or excessive consumption of sugar) do not seem to play a decisive role in the etiology of attention deficit hyperactivity.

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Attention Deficit Hyperactivity Disorder - Epidemiology

Sociological research confirms that attention deficit hyperactivity disorder is the most common mental disorder in childhood and adolescence, detectable in 5-10% of primary school pupils. In the US, more than 7% of school-age children are treated with psychostimulants (mainly methylphenidate). Psychostimulants are accepted by almost 25% of children enrolled in special programs. Deficiency of attention with hyperactivity is more common in boys, and in clinical studies the ratio is higher (9: 1) than in epidemiological (4: 1). This difference may be partly due to the fact that boys are more often referred to a doctor, or specific symptoms of attention deficit hyperactivity in persons of different sexes.

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