Question

In regards to ADHD: What are the neuronal and/or genetic findings with this disorder? For instance, what neurotransmitter type and activity is altered in this disorder? What are the findings regarding genetic influence from twin studies and gene studies? Please address at least one neuronal/neurotransmitter system and any major genetic findings.

Answer 1

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disease, in which patients suffer from executive functions such as in controlling their attention and inhibitory control. Their behaviour and hyperactivity does not correlate with their age. The symptoms appear by the age of six to twelve years and symptoms lasts for more than six months. The symptoms include hyperactivity (e.g. nonstop talking), lack of attention control, poor school performance, easy distraction, unable to follow instructions and in processing the instructions, etc.

According to twin studies, the disease is inherited from the parents in about 75% of the cases. The siblings of affected children are four times more likely to suffer from ADHD than siblings of healthy children. The affected genes are found to alter the dopaminergic neurotransmission (including MAO-A, COMT, DBH, DRD4 and 5). Other genes including SERT, BDNF, SNAP25, GRIN2A and TPH2 are also involved in the pathogenesis of ADHD.