There are 2,027 ways to be diagnosed with autism in DSM-IV and only 11 ways in DSM-5, but the numbers alone are misleading. Scientific American wanted to explore this gaping discrepancy further, so we asked astronomer and Hubble Fellow Joshua Peek of Columbia University to code a computer program that would calculate the total possible ways to get a diagnosis of autistic disorder in DSM-IV and the total possible ways to get a diagnosis of autism spectrum disorder in DSM-5. You can do the math by hand, too, if you like: It all comes down to factorials. The DSM-IV criteria are a set of 12 items in three groups from which you must choose 6, with at least two items from group one and at least one item each from groups two and three. The DSM-5 criteria are a set of seven items in two groups from which you must choose five, including all three items in group one and at least two of the four items in group two. Peek's program crunched the numbers: there are 2027 different ways to be diagnosed with autism in DSM-IV and 11 ways to be diagnosed with autism in DSM-5.
Click here to read more.