A close friend of mine was diagnosed ADHD as a kid, and not until high school was he diagnosed as having Aspergers syndrome. When he stopped taking his ritalin he had frightening visual hallucinations. I don't think people realize how much Ritalin can actually affect a kid, and in some cases I think doctors prescribe it too readily to deal with a kid's behavioural problems.
Sometimes Aspergers is MISDIAGNOSED as ADHD at first, becuase it's not a syndrome that many people know about, wheras ADD and ADHD have had lots of media in the last decade. I'd wait it out and see what the specialist has to say.
Defiance sometimes happens because people with Aspergers characteristically are happier living with their OWN routine, and I stress the word ROUTINE. Maybe it would be better for your son to be involved in a specialized program that would better suit his needs? People with Aspergers also have a tendency to be obsessive over one or two particular interest areas, such as fantasy games, computers, or aquariums, and learn about them voraciously. Your son's behaviour may improve if he is allowed to focus more on his special interests.
People with Aspergers are often also characterized as highly intelligent, though they may at first appear to be 'slow' because of poor school performance and lack of social skills (Aspergers is related to Autism). With nurturing, many people with Aspergers become very successful adults as a result of their nature to focus attention on one area. IQ tests are sometimes genius, though it may be difficult for them to express their ideas, or rather, for you and I to understand them.
Another downfall of Aspergers is that it has been associated with Bipolar, or that a person may exhibit bipolar symptoms. I'd ask the specialist about that too. Your husband is obviously being very insensitive on the issue of your illness and your difficulty in dealing with your son's behaviour. I urge you not to push for meds or anything until your son has seen the specialist. I don't know your son and I'm not a doctor, but I know what my friend went through.
My friend now repairs computers, has a huge collection of figurines he made him self, is fluent in German (reading and writing), attends and helps to organize group games, and has many good, caring friends. He remembers lines from a movie he's only seen once. He has a fabulous, if wacky, sense of humour, that is highlighted by his intelligence. He made me a beautiful sushi dinner a few weeks ago, the real deal. He's doing well for him self, becuase he was allowed to pursue his passions in an environment more flexible toward his needs and interests. He needs a boost now and then, but he's always ready to do the same for someone else.
Your son is going to be ok, and so will you, once things are under control. It sounds like your son is at an age where it's difficult to make boundaries. I see that you are frustrated, and a lot of that is because of your X husband which makes it harder for you to deal with your son. I wish you strength and the best of luck! *HUG* You are obviously one tough lady, I sincerely admire your dilligence and strength.
Check out this Aspergers website, www.aspergers.com , if you haven't already.
Hope some of that is helpful!

"SERENITY NOW!!!"