Etiology Of Attention Deficit And Hyperactivy Disorder

The etiology of Attention Deficit and Hyperactivity Diorder (ADHD) includes functional and anatomical disfunction. This disfunction occur in frontal cortex of the brain and basal ganglia segments. These regions control focus, complex motor behavior and learning processes. Symtoms of ADHD is multidimensional. The reason of it is neuroanatomical and neurochemical interaction. Recently, many researches proved that genetic and neurochemical processes play a key role on neurobiological factors.


Genetic Studies


Genetic studies applied on families (twins, siblings, adopted children, genealogy studies) showed that genetic factors play an important role on ADHD.


Molecular genetic studies focused on tyroid receptor b gene, dopamine type d2 receptor gene, dopamine carrier gene and dopamine 4 receptor gene.


Neuroanatomical Studies


Magnetic Resonance Imaging (MRI), pet and spect studies, prefrontal regions, anterior cingulate, globus pallidus, thalamus, hippocampus and cerebellum showed that volume and activity is lower in these regions.




Medication studies support the studies that show dysfunction in dopaminergic, neuroadrenergic, and serotonergic systems.


Environmental Factors


ADHD is found more on children whose mother smoke and exposed to bullet. If there is a biological predisposition, negative family relationships and bad living conditions facilitate the emergence.



(Published in website on 23.02.2011)

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