How Useful is the DSM-5?

As a psychiatrist beginning medical training in 1992, I “grew up” with the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-IV). When I was a medical student rotating on my psychiatry clerkship on the inpatient unit, I was intrigued by the patients and their various mental illnesses. As a psychiatrist-in-training, I found the DSM-IV to be quite useful clinically, as it helped to differentiate the various mental illneses, as the prognosis and treatment plan for schizophrenia would be vastly different than for depression, for instance. I kept a pocket edition of the DSM-IV in my lab coat during medical school and during psychiatry residency- I used it so much that the little book is now raggedy. In a sense, the DSM-IV justified my existence as a beginning psychiatrist, given we had no biological markers to help diagnose mental illness, and the DSM-IV was the answer to the lack of objective tests. When I rotated through the other brain specialties of neurology, neurosurgery, and neuroradiology, the attendings and trainees wondered aloud why the specialty I had chosen had not shifted from descriptive psychiatry to biological psychiatry. However, my psychiatry professors in residency training assured me that the DSM was necessary to classify psychiatric disorders so that a homogeneous sample could be followed over time to look for the biological markers associated with each particular category…psychiatrists believed then that the biomarkers for mental illness would be discovered. We psychiatrists had blind faith that psychiatry would eventually join the rest of the medical specialties and have objective biological tests to confirm our subjective clinical impressions. Back in the 1990’s, we were living in the Decade of the Brain, and large government grants were funding numerous research studies into the causes of mental illness. As a medical student and psychiatry resident in the 1990’s, I believed at the time that I had picked a medical specialty that was on the verge of new scientific advances, and would eventually have the objective biological markers to help both diagnose and cure mental illness.

Fast forward to 2013, and the DSM-5 is published. Nowhere in the book does it discuss objective biological tests for any of the disorders listed. This is the major flaw of the DSM-5. On retrospect, my colleagues in the other brain specialties knew better, that the validity of the disorders listed in the DSM were questionable without biological markers. Even with follow-up studies looking into the validity of the DSM disorders over time, only about a dozen disorders have the studies backing their validity with regards to prognosis and course. But the follow-up studies are still inherently descriptive in their methodology, and therefore is a lower level of evidence than say a blood test, brain scan, or DNA sample. Objectivity over subjectivity- circular reasoning no longer cuts it. We have described and categorized the mental disorders more than adequately…now is the time to confirm with objective evidence.

The promise of objective biological tests for psychiatry has not been realized, despite the numerous research studies that have been completed into the causes of mental illness over the past 20 years. And to make matters worse, the DSM-5 changed the names and criteria of several DSM-IV diagnoses, further adding to the diagnostic confusion known as psychiatric diagnosis.

We need to move beyond descriptive psychiatry, and really transform the field into objective, brain-based, biological psychiatry. There is nothing groundbreaking about the DSM-5…it is just more of the same labels as the previous editions of the DSM. It seems that psychiatrists have blinders on, and refuse to do away with their precious and subjective diagnostic system which has not really changed from the days of Emil Kraepelin, who founded modern psychiatry when he ushered in the classification of psychiatric illness based on syndromes and clinical course over a century ago.

In other words, psychiatric diagnosis has not really changed since the early 1900’s, over 100 hundred years ago. But we can do better with psychiatric diagnosis and psychiatry, and transform it into a real branch of medicine that is based on biology.