The American Psychiatric Association will publish a new diagnostic manual in May 2013 and this edition will contain the APA's first major rewrites in 20 years according to the Associated Press. A group of psychiatric board trustees met Saturday outside of Washington, DC to approve the changes.

Perhaps the most notable change: the terminology "Asperger's disorder" will no longer be included. The revised manual will instead include the new term "autism spectrum disorder." According to the AP, this terminology is already seen in the field; what had been recognized as Asperger's will be incorporated under this umbrella diagnosis. Autism spectrum disorder will cover a range of individuals, from mild forms to kids with severe autism who often don't talk or interact with others.

Dr. David Kupfer, chair of the task force in charge of manual revisions and a psychiatry professor at the University of Pittsburgh, told the AP the aim of the revisions was not to change the number of diagnosed mental illnesses. Rather, he says, the revisions should ensure affected children and adults receive a more accurate diagnosis and then more appropriate treatment.

We can't be certain without seeing the potential text, but Ars staffers with experience in these areas believe the dropping of the Asperger's label reflects an adaptation to current clinical procedure—it's simply a new label that won't cause any change in practice.

In theory, the revised manual will now closely reflect the subtleties and overlap between dyslexia, Autism, and ADHD, as dyslexia and other learning disorders will remain distinct categories, despite some overlap with autism spectrum. For instance, people with dyslexia can often have as much trouble focusing on tasks as those with autism, but not for the same reasons—instead, it's because dyslexics can't read the instructions. The distinctions among a diagnosis of ADHD, dyslexia, or both hinges on very careful testing.

The manual's importance runs deep, as many insurance entities use it to decide what treatments to fund and a number of schools refer to it for inclusion in special education. Other notable edits to the APA's manual include severe recurring temper tantrums coming under a new diagnosis called "disruptive mood dysregulation disorder" (DMDD). The controversial "gender identity disorder"—which many viewed as stigmatizing and incorrectly labeled as a disorder—was also dropped. The manual will now include the new "gender dysphoria," meaning emotional distress over one's gender.