12/15/2008 05:12 am ET Updated Nov 17, 2011

Why Girls With Asperger's Syndrome Don't Get Diagnosed

Liane Willey watched from behind a two-way mirror as doctors at the University of Kansas performed a series of psychological tests on her 5-year-old daughter. From the day the girl was born, Liane had worried about the child's behavior: as an infant, she would not suckle. As a toddler, she bit other children and refused to let anyone hug her. Doctors had continually assured the young mother that her daughter was normal, if a bit quirky. But with each passing year, 'quirky' had become less apt a description. By the age of 5, she had no friends and a profound obsession with monkeys. "If another kid came to school with a toy monkey or something with a monkey picture on it, she would freak out," Liane says. "She would try to take it away from the other kid, because she didn't get that not everything 'monkey' was hers." Liane had been a quirky child herself, and knew the difficult path that lay ahead for her daughter. "Growing up, I tried everything--psychotherapy, group therapy, antidepressants--none of them gave me a better sense of the world or my place in it," she recalls. "For her, I wanted something that would actually work, and I wanted them to put a name to the angst once and for all." Doctors were hoping the psychological tests would yield-up some clues.

The "Sally-Anne" test involved a simple skit: 'Sally' put a marble in the basket and then walked away. Once she was gone, 'Anne' took the marble out of the basket and put it in a box. When 'Sally' returned, the doctors asked where she would look for her marble. Anyone over the age of 5 is expected to know that Sally would look in the basket first, because she doesn't know that her marble has been moved. Expecting Sally to look in the box first suggests that the test-taker doesn't understand that other people don't know everything they know, and vice versa. Psychologists refer to this as a "theory of mind," and people who fail the Sally-Anne test are said to lack one, meaning they can't anticipate other people's thoughts and feelings. Liane's daughter failed the Sally-Anne test, along with every other assessment meant to screen for Asperger's syndrome, a high-functioning autism spectrum disorder, which the doctors promptly diagnosed her with. The good news was that they had caught it early.

It's not uncommon for girls with Asperger's to go undiagnosed well into adulthood. Like heart disease, this high-functioning autism spectrum disorder is 10 times more prevalent in males, so doctors often don't think to look for it in females. But some experts have begun to suspect that unlike heart disease, Asperger's manifests differently, less obviously in girls, and that factor is also causing them to slip through the diagnostic cracks. This gender gap may have implications for the health and well-being of girls on the spectrum, and some specialists predict that as we diagnose more girls, our profile of the disorder as a whole will change. Anecdotally, they report that girls with Asperger's seem to have less motor impairment, a broader range of obsessive interests, and a stronger desire to connect with others, despite their social impairment.