What Causes Attention Deficit Hyperactivity Disorder?

The most recent models that attempt to describe what is happening in the brains of people with Attention Deficit Hyperactivity Disorder suggest that several areas of the brain may be affected by the disorder. They include the frontal lobes, the inhibitory mechanisms of the cortex, the limbic system, and the reticular activating system. Each of these areas of the brain is associated with various neurological functions.

There are several areas of the brain potentially impacted, and there are several possible "types" of ADHD. Daniel Amen, a medical doctor using SPECT scans as identified six different types of ADHD, each with its own set of problems, and each different from the other "types." In our practice we used five different "types" of ADHD, identifying each "type" with a character from the Winnie the Pooh stories (Pooh is inattentive, Tigger is hyperactive, Eeyore is depressive, and so on).

The frontal lobes help us to pay attention to tasks, focus concentration, make good decisions, plan ahead, learn and remember what we have learned, and behave appropriately for the situation. The inhibitory mechanisms of the cortex keep us from being hyperactive, from saying things out of turn, and from getting mad at inappropriate times, for examples. They help us to "inhibit" our behaviors. It has been said that 70% of the brain is there to inhibit the other 30%.
 
When the inhibitory mechanisms of the brain aren't working as hard as they ought to, then we can see results of what are sometimes called "dis-inhibition disorders" which allow for impulsive behaviors, quick temper, poor decision making, hyperactivity, and so on.

The limbic system is the base of our emotions and our highly vigilant look-out tower. If over-activated, a person might have wide mood swings, or quick temper outbursts. He might also be "over-aroused," quick to startle, touching everything around him, hyper-vigilant. A normally functioning limbic system would provide for normal emotional changes, normal levels of energy, normal sleep routines, and normal levels of coping with stress. A dysfunctional limbic system results in problems with those areas.

The Attention Deficit Hyperactivity Disorder might affect one, two, or all three of these areas, resulting in several different "styles" or "profiles" of children (and adults) with ADD ADHD.

Learn more about the impact of ADHD on children and teens, treatment options for ADHD, and much more at the ADHD Information Library. 

Douglas Cowan, Psy.D., is a family therapist who has been working with ADHD children and their families since 1986. He is the clinical director of the ADHD Information Library's family of seven web sites, including http://www.newideas.net, helping over 350,000 parents and teachers learn more about ADHD each year. Dr. Cowan also serves on the Medical Advisory Board of VAXA International of Tampa, FL., is President of the Board of Directors for KAXL 88.3 FM in central California, and is President of NewIdeas.net Incorporated.