I am fairly certain that SPD is genetically linked, especially since it seems so linked to how a person can handle the flight & fight response. It just makes sense that as people evolved some became overly sensitive and others became undersensitive, since there are actually advantages to being more or less sensitive than the average person. Some professions require increased or decreased sensitivities.

For example: Wine tasters benefit from a more sensitive sense of smell and taste. Sports players and soldiers benefit from being less sensitive to pain.

On why people think that problems end when you are 18, I would LOVE the answer to that mystery. I guess the assumption that part of being an adult is that you have learned to compensate for your problems. People are really intollerant towards adults who develop a problem for a first time as an adult (except maybe some forms of Cancer once you start saying the Cancer word).

I have more disabilities than just SPD and co-workers were rarely tolerant of my disabilities, especially when my disabilities required them to make a lot of changes in their own lives just so I could barely function in the work force. Eventually my co-workers rebelled and purposely did things to make my disabilities activate. After being dragged off 3 times in one month from work in an ambulance I went on Short Term Disability that became Long Term Disability and then became permanent Disability.

Doodlebodd, could you describe your "nasty things" that happen to you in more detail. I am familiar with a lot of Neromuscular Diseases because of research into my own problems.