What is the DSM?
- DSM stands for Diagnostic and Statistical Manual for Mental Disorders. It is the manual published by the American Psychiatric Association which lists all classifications of mental disorders.
- The organizing concept of the DSM is to assign symptoms to the classification for which they are most relevant. For example, even if obsessive symptoms are frequently found with the manic/depressive symptoms of bipolar disorder, they would nevertheless be categorized with obsessive-compulsive disorder as they are more relevant to that category.
- Each classification contains threshold criteria for the symptoms it includes; that is, the length and/or severity which are needed for that symptom to qualify for the diagnosis.
- From time to time, the classifications are updated in order to incorporate new knowledge.
- The DSM has been enormously helpful in that it has created a single “language” with which to discuss, collaborate and diagnosis mental disorders.
- Despite this usefulness, the classifications in the DSM have not led to any major research breakthroughs. They remain concepts, or ideas of mental disorders, rather than evidence-based, validated classifications linked to known biological conditions.
- Investigators continue in their efforts to define mental disorders in ways that will provide that validation.
- There is growing recognition that the organizing concepts of the DSM are largely at odds with how our brains create behavior and that meaningful research will not be accomplished as long as it is based on DSM classifications.
In this country, formal diagnostic guidelines for mental disorders are found in the Diagnostic and Statistical Manual, published by the American Psychiatric Association. This reference source was first compiled in 1952 and has undergone five major revisions. Its categories of mental illnesses have changed dramatically over time to incorporate and reflect the evolving state of psychiatric knowledge. Today’s edition is the DSM5. It was just released in May of 2013. The manual is typically referred to simply as “DSM”.
In order to qualify for insurance re-imbursement or school classification, a formal diagnosis of a DSM classification must be made.
The “categorically” defined disorders listed in the DSM are not validated illnesses. That is, they are not based on biological evidence that distinguishes one disorder from the other. Instead, the classifications are based on the consensus opinion of experts about what a disorder might be.
Around 1980, when the current form of the DSM was established, there was an assumption that the few genetic variations which caused a disorder would create a unique set of problems or symptoms; e.g. one set of genetic variations would cause depression and another set of genetic variations would cause obsessive behavior. Therefore, it seemed appropriate to allocate symptoms into different baskets or “categories”; hence the name “categorical”.
The allocation of symptoms followed the principle that symptoms placed in any particular basket are put there because they are more important or related to each other than they are to the symptoms placed in other baskets. The experts came to decisions about which symptoms belonged with each other based on a consensus of their clinical observations. The hope was that as research continued and the baskets got more and more accurate, not only would the resulting baskets more clearly define unique disorders, but would also likely tell investigators something important about the disorder that would lead to the discovery of its source.
In addition to the conceptual approach that the experts brought to the organizing process, they also addressed a more practical one: how much of each symptom was needed for the person to qualify for that basket? To create order out of a spectrum presentation, it was necessary to impose cut-off points. Today, the DSM includes “threshold criteria” which define the degree of severity and duration required for any symptom in order for it to qualify for a diagnosis.
As mentioned above, experts gather from time to time to revisit the currently defined baskets. They use the current classifications and concepts important to those classifications as the measure by which new information should be considered. Given the fact that small changes can lead to many unintended consequences, changes are made carefully and incrementally. In the absence of an overwhelming reason to do otherwise, consistency within the manual is a priority. While the periodic reviews incorporate the new ideas and observations that have been made since the last update, actual biological evidence has not yet been able to contribute to the decision making process.
Usefulness of the DSM
The creation of the DSM has been enormously helpful in standardizing the conversation in psychiatry. Speaking the “same language” has greatly enhanced the reliability of research, teaching, and the treatment of patients.
However it is important not to lose sight of the fact that these classifications are still just efforts to adequately and usefully describe the symptom presentations with which many people struggle.
The manual itself does not claim that the classifications are otherwise. In fact, in its introduction, the authors are careful to underscore the fact that the manual is the product of collaborative discussions and that the categorically separated diagnoses, based on descriptive criteria, are meant to be used as conceptual guides rather than be considered validated entities with proven boundaries. To date (2013) only a few of the 300+ classifications have been validated.
The experts who decide on the revisions are acutely aware of the problems that accompany defining illnesses based on ideas rather than evidence. The field as a whole struggles to move towards a more reliable, accurate and effective system. While important new research points out how inadequate the current system may be, the new information is not yet ready to make a massive change to the system as a whole. The current version of the DSM has made a beginning attempt to address the spectrum aspect of disease as well as to capture/consider evidence of behavioral dimensions which cut across classifications. However, previously defined classifications continue to be the basis from which adjustments are made.
Too Much Familiarity
Decades of widespread use of these classifications makes it easy to forget that they are just ideas. Names like bipolar disorder, schizophrenia, separation anxiety are so familiar that we may think of them as having the same legitimacy as bronchitis, astigmatism or high blood pressure. When someone says, “My daughter has bipolar disorder,” the more accurate statement would be: “My daughter has a set of symptoms which are included in an idea called “bipolar disorder”. It’s not that the girl doesn’t have the symptoms. And it’s not that they are not part of an illness. It is just that it is yet to be determined if the idea of “bipolar disorder” is the correct way to think of them.
Future of the DSM
Recent breakthroughs in science and technology have started a transition away from the DSM. To read more, go to What is a Brain Disorder. To read a commentary by the Director of the NIMH regarding DSM5, click Research Domains, Director’s Blog 3/13. To read a New York Times editorial on the state of diagnoses and DSM5 click here.