The Biology of ADHD

The prevalence of ADHD is 3-7 percent of the population. But what is ADHD? Psychologists identify it using a constellation of symptoms that can be both observed and measured. The particular diagnostic criteria for ADHD is defined in other articles in my blog on this site. This article will focus on the biology of ADHD.

Like many psychological diagnoses, ADHD has a biological and genetic component. The first symtoms of the disorder are usually noted by a child’s parents or teachers often prior to beginning kindergarten. The symptoms are noted by a pattern of behavior involving impulsiveness, inattention or both. Children, or adults for that matter, with ADHD possess different brain biology from those without the disorder. These differences can be noted in brain scans of the frontal lobes of the brain. The frontal lobes help us to pay attention to tasks, focus concentration, make good decisions, plan ahead, and learn and remember what we have learned. The frontal lobes also help us to behave appropriately for a given situation. These abilities are known as Executive Functions. These functions are most impacted by ADHD.

The inhibitory mechanisms of the frontal cortex keep us from being hyperactive, from saying things out of turn, and from getting mad at inappropriate times. It has been said that 70% of the brain is there to inhibit the other 30% of the brain. People with ADHD thus have often been noted to act impulsively and to not be able to inhibit behavior that should be inhibited. When the inhibitory mechanisms of the brain aren’t working effectively, we can see results of what are sometimes called “dis-inhibition disorders” such as impulsive behaviors, quick temper, poor decision making, and hyperactivity.

The limbic system is the base of our emotions and our highly vigilant look-out tower. If the limbic system is over-activated, a person might have wide mood swings, or quick temper outbursts. He might also be “over-aroused,” quick to startle and hypervigilant. A normally functioning limbic system would enable one to exibit emotional flexibility, normal levels of energy, normal sleep routines, and the ability to cope with stress. A dysfunctional limbic system results in problems with those areas.

Attention Deficit Disorder may effect these regions of the brain causing the behaviors noted by parents, teachers and therapists. The question then becomes, what to do to help mitigate the effects of ADHD? Due to its biological root, medication can often be a helpful tool in lessening the severity of symptoms. Additionally, people with ADHD need to learn how to compensate for their innate inability to focus or to inhibit impulsivity. Therapists can help to facilitate this aspect of the treatment. Also, the child’s school needs to be a part of the support system to effectively deal with ADHD. It can be of crucial importance for parents to seek out psychological testing administered by psychologists in order to effectively define the presence of ADHD, the type of ADHD, and the extent to which symptoms inhibit academic success. Effective multimodal treatment beginning with correct assessment and diagnosis can help a child or adult with ADHD to function adaptively in spite of their symptomsn