Asperger's syndrome is to be dropped from the psychiatrists' Diagnostic and Statistical Manual (DSM) of Mental Disorders, the American publication that is one of the most influential references for the profession around the world.

The term "Asperger's disorder" will not appear in the DSM-5, the latest revision of the manual, and instead its symptoms will come under the newly added "autism spectrum disorder", which is already used widely. That umbrella diagnosis will include children with severe autism, who often do not talk or interact, as well as those with milder forms.

The British hacker Gary McKinnon is diagnosed with Asperger's and it contributed to a government decision not to extradite him from Britain to the US on cybercrime charges.

The DSM is used in a number of countries to varying degrees. Psychiatrists in some countries including Britain use the International Classification of Diseases (ICD) published by the World Health Organisation or a combination of both handbooks.

In other changes to the DSM, abnormally bad and frequent temper tantrums will be diagnosed as DMDD, meaning disruptive mood dysregulation disorder. Supporters say it will address concerns about too many children being misdiagnosed with bipolar disorder and treated with powerful psychiatric drugs.

The term "gender identity disorder", for children and adults who strongly believe they were born the wrong gender, is being replaced with "gender dysphoria" to remove the stigma attached to the word "disorder". Supporters equated the change with removing homosexuality as a mental illness in the diagnostic manual decades ago.

The revisions come in the first major rewrite in nearly 20 years of the diagnostic guide used by psychiatrists in the US and other countries. The changes were approved on Saturday.

Full details of all the revisions will come in May 2013 when the American Psychiatric Association's new diagnostic manual is published. The changes will affect the diagnosis and treatment of millions of children and adults worldwide, as well as medical insurance and special education services.

The aim was not to expand the number of people diagnosed with mental illness but to ensure those affected were more accurately diagnosed so they could get the most appropriate treatment, said Dr David Kupfer, the University of Pittsburgh psychiatry professor who chaired the revision committee.

One of the most hotly argued changes was how to define the various ranges of autism. Some on the panel opposed the idea of dropping the specific diagnosis for Asperger's. People with that disorder often have high intelligence and vast knowledge on narrow subjects but lack social skills. Some Asperger's families opposed any change, fearing their children will lose a diagnosis and no longer be eligible for special services, but experts have said this will not be the case.

People with dyslexia also were closely watching for the update. Many with the reading disorder did not want their diagnosis dropped, and it will not be. Instead, the new manual will have a broader learning disorder category to cover several conditions including dyslexia, which causes difficulty understanding letters and recognising written words.

The shorthand name for the new edition, the organisation's fifth revision of the Diagnostic and Statistical Manual, is DSM-5. Group leaders say specifics will not be disclosed until the manual is published but they confirmed some changes. A 2000 edition of the manual made minor changes but the last major edition was published in 1994.