The DSM-5, the latest revision of the “bible” of mental health disorders, will be issued within days. It’s been 13 years since the last update, and it could have a significant impact on the diagnosis, treatment and funding of a number of currently recognised mental health disorders — from addiction to Asperger’s. But not everyone is happy about it.

The DSM is shorthand for the solemnly titled Diagnostic and Statistical Manual of Mental Disorders, the framework psychiatrists and others in the mental health profession use to diagnose disorders and psychiatric conditions. Developed and published by the American Psychiatric Association, it’s generally considered the definitive text on what constitutes a mental disorder. The current edition is the DSM-IV-TR (text revision) was published in 2000; the new manual will be released at the APA’s annual meeting in San Francisco this weekend.

The association says its manual — the fifth major revision of the text, in development for 14 years after consulting some 500 specialists — “helps to ensure that a diagnosis is both accurate and consistent” by clearly setting out the description, symptoms and various markers of a mental disorder. But it doesn’t give any advice on treatment; those who like self-diagnosis won’t find any tips.

In the US, in particular, the DSM forms a basis for funding allocation for welfare and for the benefits health insurers pay, so changes to categorisation can have a big effect not only on people’s understanding of their diagnosis but also the money in their pocket.

Like a lot of scientific advancements of the 20th century, the DSM came out of the US military. When the US entered World War II, psychiatrists took a key role in the administration of the war effort, assessing troops’ mental health during the initial selection process and then throughout service until discharge. After the war, in 1946, the War Department issued a technical bulletin to all armed forces under the unassuming title of “Medical 203“. This was the first modern attempt to categorise mental disorders, taking advantage of the unique opportunity that having a committee of prominent psychiatrists, a large diverse sample and a war-time budget provided.

In 1948, two years after the Medical 203 came out, the APA started work on creating the standardised psychiatric assessment tool that would become the DSM. After four years of development, and probably a lot of squabbling, the first edition was published in 1952. It was just 130 pages long and included 106 disorders; vast sections of the text, and its framework, were copied wholesale from Medical 203.

Over time, the number of recognised disorders has almost tripled: the DSM-IV contains 297 disorders over 887 pages.

Since then it’s been a work in progress. Homosexuality was considered a mental disorder by the APA until a revision of the DSM-II in 1974. It took years of earnest campaigning by gay rights organisations, and submissions by sexologist Alfred Kinsey and prominent gay psychologist Evelyn Hooker for the change to come. A category called “ego-dystonic homosexuality” allowed psychiatrists to diagnose patients uncomfortable with their homosexuality as having a disorder (something which gay rights activists have argued may have more to do with society at large than the individual) — it was included in the DSM-III until a minor revision in 1987.

One of the most controversial changes, flagged through the consultative process, is the incorporation of Asperger’s disorder into the broader autism spectrum disorder. Asperger’s was only recently included (in the DSM-IV), but the DSM-5 taskforce has found there has not been enough clarity between high-functioning autism and Asperger’s to make a definite diagnosis of one or the other.

There are some significant changes across the DSM (including the system used to categorise people within a disorder, the axial system). But for most, it is changes to specific disorders that provide the biggest point of interest — and, in some cases, greatest source of angst. These include:

  • Autism and Asperger’s are now under the one disorder. Autism spectrum disorder, a new category in the DSM-5, will group autistic disorder, Asperger’s disorder, childhood disintegrative disorder and pervasive developmental disorder under the one heading. People who have struggled to get funding and acknowledgement for Asperger’s disorder as a separate condition don’t see this as a positive change. The number of people who will qualify as having ASD is also controversial — some estimates suggest only 60% of people currently diagnosed with autism under the DSM-IV criteria would meet the DSM-5 definition.
  • Some interesting new disorders have been recognised. Conditions newly added in the DSM-5 include binge eating disorder, excoriation disorder (compulsive skin picking), hoarding disorder (which begs the question of how the reality TV show will survive when hoarding becomes a legitimate condition) and internet use gaming disorder (surely a prime candidate for new self-diagnosis, and also known as internet addiction disorder).
  • Depression no longer has a bereavement exclusion. The DSM-IV incorporated an exclusion for people demonstrating depressive symptoms who had lost someone close to them within two months of diagnosis. This has been omitted from the DSM-5, and while there is additional information on delineating grief and depression, many experts feel this could muddy the waters of diagnosis.
  • Disruptive mood dysregulation disorder will stop kids from being diagnosed as bipolar. The APA has acknowledged what has been seen as a “potential over-diagnosis and over-treatment” of bipolar disorder in children and has created a new category to address the issue.

Thanks to the internet, the process of the DSM-5’s development has been transparent in a way that was never before possible; draft changes were posted online for comment in 2010. As a result, critics have been on the front foot for some time. Thomas Insel, director of the US National Institute of Mental Health, wrote in a blog post last month that he believed it was time for a shift away from symptom-based diagnosis and toward diagnoses that incorporate “genetics, imaging, cognitive science and other levels of information to lay the foundation for a new classification system”. And bible? Insel says it’s, “at best, a dictionary”.

Since June 2011, the NIHM HAS been working on a project to develop new, more scientific systems under the title Research Domain Criteria. It’s still a research project, but Insel believes it will bring mental health patients a step closer to “precision medicine”.

Closer to home, the Australian Psychological Society made a 26-page submission last year. One of its main criticisms is the growing divide between the World Health Organisation’s International Classification of Diseases and the DSM. The submission notes “any classification of disorders [should attempt] to capture problems experienced by humanity rather than problems of a specific culture”, and the divide between the two systems could limit international understanding, research and diagnosis in mental health.

While it’s clear the DSM-5 will still perform a fundamental task in mental health diagnosis, there’s an uphill battle to accommodate the many misgivings mental health practitioners and sufferers have with its revisions.

*This article originally appeared on The Citizen, a new publication of the Centre for Advancing Journalism at the University of Melbourne