What are the causes of attention deficit hyperactivity disorder? Genetic and environmental factors influence the development of ADHD, as with other developmental psychiatric disorders.
Research confirms that attention deficit hyperactivity disorder is a familial problem. Its heritability rate is estimated at 76%, one of the highest among psychiatric disorders.
Non-genetic conditions also play a role in the development of ADHD, such as:
- perinatal stress;
- low birth weight;
- damage to the central nervous system;
- smoking, drug use, alcohol consumption, maternal intake of psychoactive drugs during pregnancy;
- severe early emotional deprivation;
- exposure of the foetus or child early in life to environmental toxins, e.g. lead, pesticides, polychlorinated biphenyls.
The emergence of ADHD symptoms is explained by, among others, Russel Barkley’s theory. According to this author, the development of the symptoms of the disorder is related to a deficit of inhibitory and control functions of the central nervous system. The consequences of the inhibitory deficit are:
- excessive motor activity;
- impulsivity;
- increased metastability of attention;
- a lack of internal monologue for self-instruction during activity.
Inhibition deficit is a genetically determined temperamental trait or the result of damage to the brain structures responsible for controlling behaviour.
Neuroimaging studies confirm differences in brain structure and function in children with ADHD. Changes have been demonstrated in the size, proportion and blood flow and metabolism of the prefrontal cortex, basal nuclei, great spiracle and cerebellum.
Source / Bibilography
- https://www.damian.pl/zdrowie-psychiczne/adhd/
