ADHD, or Attention Deficit Hyperactivity Disorder, has become an all too common diagnosis these days. In fact, according to the CDC, nearly 1 in 10 children (9.5%) had been diagnosed with ADHD in 2007. With the diagnosis growing at a rate of 5.5% per year on average, the number of cases is well above that today. Unfortunately, that increase in incidence has not been followed by an increase in understanding of the disorder, and there are still many myths and misconceptions concerning the causes and available treatments.
The first myth is that ASD's (Autism Spectrum Disorders) are a purely genetic disorder. Up till now, most research into ASD has been directed at finding the genes involved in the hopes of developing more effective treatments. Some progress has been made in this area and genes controlling development of dopamine regulating systems in the brain have been implicated as part of the problem, but no definite "smoking gun" gene, or set of genes, have been found as yet. Furthermore, the dramatic increase in cases we have today would tend to discourage the idea of a purely genetic cause.
Another myth is that this epidemic increase is due to better diagnostic tools. However, a study in California showed that the increase in ASD cases could not be credited to better diagnosis alone and we needed to better identify the environmental factors involved.
Misconceptions abound as to what exactly is happening in the brain of these kids. What we can see on imaging is that there are certain parts of the brain that are under-developed and some areas that are over-developed, leading the unevenness in skills commonly seen. Some consider the problem to be a dopamine shortage in the brain, and this is the basis of the main form of current treatment, Methylphenidates (Ritalin and others). While the drugs are a useful tool in controlling the disorder, it is not a cure. These kids are on the drugs for years and their symptoms return once they are discontinued. Furthermore, prolonged use of them has been associated with unwanted side effects of growth suppression.
One theory that is gaining ground in the research is the idea of ASD's as a form of "Functional Disconnect Syndrome". In this model, there is a relative underdevelopment of connections in one hemisphere of the brain (usually the right in ADHD and Autism) and a corresponding over-development of connections in the other hemisphere. This leads to poor gross motor skills, focus, and reading facial emotions/eye contact (all relative right hemisphere functions) and normal or overdeveloped fine motor skills, attention to detail, and repetitive movements, actions or thoughts (all relative left hemisphere functions). The deficient gross motor skills explains the missed developmental milestones we often see in kids with these disorders such as sitting up, crawling, and walking. The overdeveloped left hemisphere explains the Savant Syndromes we sometimes see we see in autism.
This new theory of the mechanisms involved in ASD's is leading to new options for treatment of them as well. The brain grows and develops through sensory input. New treatment options based on this model include "multi-modal" brain stimulating exercises in the hopes of creating growth in the underdeveloped circuits of the deficient hemisphere. These "Hemisphere Specific Remediation" exercises focus on the deficient hemisphere only and can include motor/balance input, light and sound inputs, in addition to cognitive behavioral therapy. The initial results of research of these treatments are positive and encouraging.
As the ADHD/Autism epidemic continues to grow, it's good to know that science is starting to provide some answers to what is causing it, and providing some possible new options in treating it. As is the case in most things, being informed is the best defense for both our own families and society as a whole.