Attention deficit hyperactivity disorder (ADHD) and autism are conditions which are typically diagnosed in childhood, though adults have these conditions as well. ADHD and autism are separate and distinct conditions, but researchers have found that there are some connections or similarities between these conditions. For example, the connections between ADHD and autism pertain specifically to the similarities in some of the behaviors exhibited and the similarity in their chromosomal location.
Although there are differences between the two conditions, there are also similarities. Both autistic and ADHD children may display tantrums or disruptiveness in their actions, and there could be inappropriate giggling, laughing, interruptions, or talking. There may be little eye contact or the child may not appear to listen to instructions. The child may be impulsive or may seem to make careless mistakes often. There will be inconsistency or problems in fine and gross motor skills.
As researchers are now more knowledgeable about genetics than they have been in the past, they are able to seek information pertaining to the genetic cause of various conditions. This type of research goes to the heart of how and why conditions occur from a physical perspective. In a study published by the American Journal of Human Genetics, researchers found that despite the fact that ADHD and autism differ, they are actually both located on chromosome 16.
At first, it was not fully understood how chromosome 16 could be involved in both ADHD and autism because, although there are similarities, there are also marked differences in the outward display of symptoms in each condition. Later, some researchers thought that genes are not necessarily always specific to solely one diagnosis. In other words, they thought that one gene could potentially predispose a person to develop a range of conditions as opposed to just one condition. They thought that it is possible that chromosome 16 predisposed a person to ADHD, autism, or any one of several conditions as opposed to chromosome 16 being predictive of just one condition.
Of note, although researchers have found that autism and ADHD are located on the chromosome 16 location, researchers nonetheless still suspect that environment-related factors are also involved in these conditions. For example, they believe environment impacts the expression of chromosome 16 and plays a role in determining whether a person will have ADHD or autism. Research into this issue is ongoing and researchers are making an effort to further determine the nature of the interaction between genetics and environment pertaining to ADHD and autism.