What is a diagnosis

What is a diagnosis. 
A frequently asked question is, “well doc, what is my diagnosis?” My usual answer is, “you are kind of a  mixed bag”. Let me explain. 
As I have probably said in a previous post, “all psychiatrists have physics envy”. That is to say, we all wish  to have some mathematical model that will explain the human condition so that we can simply plug in  the appropriate variables and out pops the correct answer or explanation. Although physics and  chemistry determine all of biology and therefore our brain and its emergent property the mind, at the  emergent level of the mind we cannot deal in that level of precision. What we can say about the mind is  that it is noisy and non-linear. With this as background, what then is a diagnosis? 
A diagnosis is a constellation of symptoms, both subjective and observed, that tend to cluster together  as a behavioral state that impairs normal daily functioning. These states have been known since humans  have been human and talking about other humans. Over the span of recorded human history, they have  gone by different names and different explanations have been given for their existence. These states if left untreated tend to have a distinct course of symptom evolution over time. This is true of all medical  illnesses. The exact makeup of the symptom clusters has varied over the course of human history. Our  current diagnostic schema is determined by a committee of the American Psychiatric Association (which  happens to own the copyright to this schema). The naming has nothing to do with the underlying  biology (illness). If you are now thinking this is no way to practice medicine, you would be correct. 
Let us take the example of PTSD. Please be advised that I am shamelessly reciting facts presented by my  colleague, Dr. Amit Etkin, for this example. His videos on this subject can be found on You Tube. In DSM 3, the previous iteration of our diagnostic schema, (the diagnostic manual devised by the above  referenced committee) there were 80,000 different combinations of symptoms that will yield a  diagnosis of PTSD. Just a few years later this same committee revised the criteria for PTSD (DSM-4).  Now there are 600,000 combinations of symptoms that will lend a diagnosis of PTSD. To complicate  matters further, there is only a 50% overlap in these combinations between the two different versions  of the same PTSD diagnosis. The biology of PTSD surely did not change during this time and neither did  the emergent properties of the biology. What changed was the way the committee decided to slice and  dice these emergent properties. If about now, you are thinking of the story of the blind men feeling the  elephant, you would be correct. 
With this is background, a few more facts can be stated about psychiatric diagnosis. 
In general, a psychiatric diagnosis is not “one thing”. Take for example, major depression. The diagnosis  includes disorders of sleep (too much or too little), appetite changes (too little or too much), decreased  energy, decreased motivation, psychomotor agitation or retardation, decreased concentration and  indecisiveness. We know from functional imaging studies and neurophysiology, that for the most part, each of these symptoms is controlled by a different neural pathway. In addition, you can see that within  a given pathway the changes may be in totally different directions. Given this, I find it amazing that  sometimes a single intervention will address all these changes. More often, multiple interventions are  required to fully address all the various changes in the various pathways. 
Psychiatric diagnoses often overlap. One example of this is the diagnosis of depression and anxiety.  There is an old saying in psychiatry that one can be anxious without being depressed but one cannot be 
depressed without being anxious. More often than not, that is born out in the clinic. Let us look at one  of the most used rating scales of major depression, the Hamilton Depression Rating Scale. The first  three items address mood, guilt and suicide, all exclusively depressive symptoms. The next three  questions address insomnia which is disordered in many different conditions including anxiety. The next  question addresses work and activities and the next question addressed psychomotor retardation. The  anchor points of these questions favor the disability being in the depressive spectrum. The next seven  questions address some form of psychic or somatic manifestation of anxiety. The remainder of the  scales addresses various varieties of depression such as melancholic and psychotic. 
As you can see from this one example, and there are many more, a psychiatric diagnosis is seldom either/or but more likely “and”. 
Sapien Labs developed the Mental Health Quotient. This is an online rating scale of mental well being  that spans across the various diagnoses (transdiagnostic). You may take the rating scale at the Sapien  Labs website. The researchers broke the sample into a clinical group that was being treated for any  diagnosis and a group that was “at risk” based on their responses to the rating scale. Both groups  displayed “severe” symptoms. 
In the clinical group, the percentage of the group with one or more diagnoses were  approximately as follows: no diagnosis (dx)=5%, 1 dx=13%, 2 dx=12%, 3dx=11%, 4dx=14%, 5dx=12%, 6=10%, 7dx=8%, 8dx=8%, 4dx=9%, 10dx=1%. 
In the at-risk group with severe symptoms, 60% had no diagnosis and 20% had 1 diagnosis, 9%  had 2 diagnoses. 
Once again, if you are thinking this is not a good way to practice medicine, you are correct. What this practice is doing to improve on this situation will be addressed in future posts.


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