Psychologist examines methods of classifying mental disorders

December 7, 2017 by Brittany Collins Kaufman
Lee Anna Clark, William J. and Dorothy K. O'Neill Professor of Psychology at the University of Notre Dame. Credit: University of Notre Dame

Mental illnesses, such as major depression, bipolar disorder and post-traumatic stress disorder, affect nearly 1 in 5 adults in the United States, according to the National Alliance on Mental Illness. Many aspects of these illnesses remain something of a mystery, despite the progress made in understanding them by researchers studying these disorders in the last half century.

Even so, clinicians and researchers, together with patients and their families, have made significant strides identifying and treating mental illnesses. Two major diagnostic manuals—the Diagnostic and Statistical Manual of Mental Disorders (DSM), used primarily in the U.S., and the International Classification of Diseases (ICD), used internationally—provide clinicians, researchers and patients a structured approach to diagnosing . Further, the federal National Institute of Mental Health also uses a new framework for researching mental illness, called the Research Domain Criteria, or R-DoC.

Although these manuals are helpful and even necessary for identifying and treating mental illnesses, Lee Anna Clark, William J. and Dorothy K. O'Neill Professor of Psychology at the University of Notre Dame, along with a small team of other experts, wants researchers and clinicians to revisit how these illnesses are approached. In a new paper published in the invitation-only journal Psychological Science in the Public Interest, Clark and her team present the challenges in using these manuals from a scientific perspective and offer some recommendations for re-conceptualizing the they describe.

"The phenomenon of mental illness or psychopathology is much more complex, much more multi-determined, much less categorical than any of us ever thought going into it and than the public realizes," Clark said.

Clark and her co-authors identified four challenges to understanding and classifying mental disorders: what varied combinations of factors cause them, how to diagnose them given that they are not actually distinct categories, thresholds for diagnosis and other purposes such as treatment, and co-morbidity—the fact that most people with mental illness meet the diagnosis for multiple mental disorders.

"For many years people had the idea that mental disorders had single, simple causes like streptococcus causes strep throat, that sort of thing," Clark said. "But as we learn more and more about mental disorders, that's just absolutely not the truth. They're caused by multiple factors. They have genetic and other biological causes, plus environmental influences, both personal and cultural. It's very complex."

People typically can be diagnosed with more than one mental , Clark said—for example, an individual diagnosed with usually also meets the criteria for an anxiety disorder. But disorder combinations do not happen by chance.

"There are patterns to the combinations. It's not random, as though if you have this disorder you could have any one of the other 300 to 400 or so disorders. And the fact that there are patterns suggests there are some underlying features that create these patterns," Clark said.

Researchers are trying to understand those patterns. "Major depression and generalized anxiety disorder, which sound different, co-occur far more often than they appear singularly," Clark said. "Genetic studies have shown in fact that that commonality is almost entirely due to a particular set of genes. We don't know what genes, but we have the technology to be able to say that the covariation, the fact that they co-occur, is genetically based. We can't be specific about it yet. So if the same set of genes are one of the factors causing them, then in no real way are they completely separate disorders, right?"

Psychologists are continuing to work on the DSM and ICD: The fifth revision of the DSM was released in 2013, and the 11th version of the ICD is due next year.

In America, the DSM "is sort of the Bible" for making mental disorder diagnoses, Clark said. It's relied on by health care providers, insurance companies, researchers and others. The ICD, developed by the World Health Organization originally to track health statistics, is the primary diagnostic system used outside the U.S.

"Getting a diagnosis of a mental disorder has all sorts of social ramifications," Clark said. "Both negative, with some stigma attached to it, and also positive—certain individuals who get a diagnosis are then eligible for various services. If you can't get that diagnosis you can't get those services."

Clark would like to see a deeper discussion among researchers, clinicians and even the government into what it means to diagnose and how that affects people.

"For example, educational institutions have an obligation not to perpetuate the myth that mental disorders are these simple, singular diseases, like we'd like to think they are," she said. "Probably the vast majority of people with mental will never see a professional worker. It's an issue that's much more widespread than educating a small cadre of mental health care professionals. It's really a broad social problem that we need to address."

Explore further: Women with PCOS should be screened for mental health disorders

More information: Lee Anna Clark et al. Three Approaches to Understanding and Classifying Mental Disorder: ICD-11, DSM-5, and the National Institute of Mental Health's Research Domain Criteria (RDoC), Psychological Science in the Public Interest (2017). DOI: 10.1177/1529100617727266

Related Stories

Women with PCOS should be screened for mental health disorders

November 6, 2017
Women with PCOS are more likely to suffer from mental health disorders and should be routinely screened for these during medical assessments, according to a study presented at the Society for Endocrinology annual conference ...

New diagnostic model for psychiatric disorders proposed

April 5, 2017
University of Otago researcher Associate Professor Martin Sellbom is part of a group of 50 leading international psychologists and psychiatrists who have put forward a new, evidence-based, system for classifying mental health ...

Streptococcal throat infection linked to mental disorders

May 26, 2017
(HealthDay)—Individuals with streptococcal throat infection have increased risks of mental disorders, especially obsessive-compulsive disorder (OCD) and tics, according to a study published online May 24 in JAMA Psychiatry.

CAMH study shows mental illness associated with heavy cannabis use

April 2, 2013
People with mental illnesses are more than seven times more likely to use cannabis weekly compared to people without a mental illness, according to researchers from the Centre for Addiction and Mental Health (CAMH) who studied ...

More than half of all opioid prescriptions go to people with mental illness

June 27, 2017
Fifty-one percent of all opioid medications distributed in the U.S. each year are prescribed to adults with mood disorders such as depression and anxiety, according to new research from the University of Michigan and the ...

How frequent are mental disorders in cancer patients?

September 22, 2016
In an investigation published in the current issue of Psychotherapy and Psychosomatics a group of German investigators provides the largest survey of mental disorders in cancer. Psychological problems are common in cancer ...

Recommended for you

Suicidal thoughts rapidly reduced with ketamine, finds study

December 14, 2017
Ketamine was significantly more effective than a commonly used sedative in reducing suicidal thoughts in depressed patients, according to researchers at Columbia University Medical Center (CUMC). They also found that ketamine's ...

Do bullies have more sex?

December 14, 2017
Adolescents who are willing to exploit others for personal gain are more likely to bully and have sex than those who score higher on a measure of honesty and humility. This is according to a study in Springer's journal Evolutionary ...

Eating together as a family helps children feel better, physically and mentally

December 14, 2017
Children who routinely eat their meals together with their family are more likely to experience long-term physical and mental health benefits, a new Canadian study shows.

Children's screen-time guidelines too restrictive, according to new research

December 14, 2017
Digital screen use is a staple of contemporary life for adults and children, whether they are browsing on laptops and smartphones, or watching TV. Paediatricians and scientists have long expressed concerns about the impact ...

The iceberg model of self-harm

December 14, 2017
Researchers have created a model of self-harm that shows high levels of the problem in the community, especially in young girls, and the need for school-based prevention measures.

Anti-stress compound reduces obesity and diabetes

December 13, 2017
For the first time, scientists from the Max Planck Institute of Psychiatry in Munich could prove that a stress protein found in muscle has a diabetes promoting effect. This finding could pave the way to a completely new treatment ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.