Though treatment helps at every age, Klin says, "We know the earlier we start treating these conditions, the more likely we are to make a dent in the natural course of the condition."
Darius McCollum, who was diagnosed just six years ago at the age of 37, hasn't received much treatment for the condition. "You can never catch up with him," Elizabeth says.
He did, however, attend a handful of meetings of GRASP, the Global and Regional Asperger Syndrome Partnership.
"After the diagnosis, he had been sent to us," says Michael John Carley, the executive director of GRASP, who also has Asperger syndrome. "There was the usual amount of huge relief that you see in most adult diagnoses. Suddenly there is a reason for so much that has gone on in the past that you haven't been able to explain."
Though Darius hasn't participated much in GRASP, Carley still stays in touch with him, even during Darius' times in jail.
"He is a very well-spoken, very likable guy, which is really hard to believe when you look at the iconography of someone who's spent more than half of his adult life behind bars," Carley says.
The solution to his criminal problem, Carley says, would have been for the Manhattan Transportation Authority to hire him. "He would have been their best employee."
Darius agrees, saying that he is "overqualified" for a position there but that his criminal record has prevented it.
The New York City Transit declined to comment on his actions or any personnel inquiries.
"I figure that if I had gotten in the system the way I wanted to, I should be general superintendent or chief by now," he says.
After his most recent arrest, Darius faces a decision.
"He has a very, very hard choice to make," Carley says. Darius can try to make a life for himself or he can continue with his criminal behavior, he explains.
Darius says that he has chosen his path already.
Though he loves New York, he says he's trying to get a job where people don't know as much about his reputation. He'd like to get certified as a track inspector in a Southern state and start working on small railroads.
When he was younger, Darius says he didn't think about how risky it was for him to operate trains without official instruction. But as he's gotten older, he understands the concern.
"I think about how dangerous it can be now ... how more people could be hurt, even though I don't do anything when I'm down there," he says about his time spent in the subway recently.
Still, he adds, "I don't go down there to hurt anybody. I just go down there because I still love the system."