Getting a Diagnosis as an Adult with Asperger’s

Is it worthwhile undergoing diagnostic testing if you’re an adult and you suspect that you have Asperger’s? That’s a question that seems to come up frequently. There are pros and cons and no answer is right for everyone. But, it can be helpful to look at the experiences of others.
Last month (September-October 2008), Autism Asperger’s Digest Magazine published an article entitled "Better Late Than Never", by Douglas Hogetvedt. The author was diagnosed with Asperger’s at the age of 49, and he writes about his experience with later life diagnosis. Some of the points he raises are that with the diagnosis his life “finally made sense.” He discusses how his diagnosis helps him understand his past, and makes him feel energized about his future. Hogetvedt did a lot of his own research through books and online before getting a formal diagnosis from a psychologist. He also talks about how difficult it was to find a professional who works with adults on the autism spectrum.
In the memoir Look Me In the Eye: My Life With Asperger’s, author John Elder Robison, discusses his own diagnosis at the age of 40. Like Douglas Hogetvedt, Robison first considered his own condition after learning about Asperger’s from a friend. Robison was given the book Asperger’s Syndrome, by Tony Attwood. He describes reading the book and experiencing relief that there were others like him. “All my life, I had felt like I didn’t fit in. I had always felt like a fraud or, even worse, a sociopath waiting to be found out.” (p. 238) Robison questions how his life might have been different if he’d had the knowledge earlier, and how he missed opportunities for relationships and education. He discusses how the diagnosis helps him feel that his knowledge and abilities are both rare and legitimate.
The other interesting point is how Robison used his knowledge of Asperger’s to understand the neurotypical world, and how he started making some conscious efforts to behave differently. He states that those changes resulted in getting different reactions from those around him. He defines this as moving from “being weird to being eccentric” (p. 240)  and that the confidence his diagnosis gave him helped him to make friends. Robison also makes the point that he’s not defective, and that his Asperger’s traits contribute to his strengths.
The Complete Guide to Asperger’s Syndrome, by Tony Attwood (p. 29) has a long discussion of the pros and cons of diagnosis for both children and adults. It’s too lengthy to summarize here, but certainly worth checking out. Attwood gives mostly positives of diagnosis, but has a few cautions as well.
So how do you get a diagnosis if you want one? The ideal is to find a psychologist who specializes in autism and Asperger’s and who works with adults. Some medical doctors are very familiar with the diagnosis, others don’t have much experience in testing or with Asperger’s. There is no blood test or simple, universal method to test for Asperger's, so the experience of the professional is important. If you’re just looking to get some understanding of yourself, and you don’t want a formal evaluation, you can start with the scales published by Simon Baron-Cohen. The Essential Difference: Male and Female Brains and the Truth About Autism (2003) has a range of self tests in the appendix that you can take before seeking professional advice.
(As a final point, I’ll end by stating that I am not giving medical advice. Please seek professional advice if you have concerns about medical issues.)