[Posted on 6 March, 2018 by David Eberhard]
All psychiatric diagnoses are syndrome diagnoses. Nothing strange about that, in fact the vast majority of medical diagnoses even outside the field of psychiatry are given based on the patient manifesting a number of symptoms. What separates psychiatry from other fields is that these symptoms cannot be verified using biological markers of different kinds. In my last article on the Gillberg blog, I addressed this fact and problematised it.
Even so, for a long time, people in the field of neuropsychiatry have tried to complement clinical data with different types of psychological tests in order to verify their diagnoses. Adult psychiatric services have performed intelligence tests on virtually all patients even in cases where the patient has obviously been of normal intelligence and the differential diagnosis thus clearly could not have been intellectual disability. Many have then proceeded to interpret certain intelligence test responses as typical of e.g. ADHD, even without much support for any such claims in scientific literature. Moreover, in line with typical neuropsychiatric examinations, other tests evaluating executive functions have regularly been given to patients without any pathognomonicity for ADHD or autism spectrum disorders. This has of course been good in the sense that it provides an opportunity to obtain more information, but given that the diagnoses primarily constitute a constellation of symptoms without any given common cause, tests can never guarantee a correct diagnosis. For example, a person might be suffering from attention problems and hyperactivity for reasons so different that there would be no certainty at all that they would manifest in any tests, even though the symptoms present an actual, real problem. By the same token, a person with pronounced difficulties in experimental test situations might in some cases get by just fine in everyday life. Aside from that, the causes behind someone having pronounced issues might be found somewhere entirely different than in neuropsychiatry. So even if someone has difficulties with a given test, it does not say anything about the actual diagnosis.
The opposite represents another complicating factor. Symptoms traditionally argued to originate in the person’s childhood years, and which are thus referred to as neuropsychiatric, might not always meet the clinical criteria for ADHD, autism, or some other diagnosis. They might only manifest in adults as anxiety disorder or depression. And no tests are ever performed to verify such diagnoses. Instead, there is often a tendency to only compile more and more symptoms, without ever trying to find out what the cause is or properly checking when the symptoms first started to occur. Another common tendency is to disregard whether a person has any objective reason to feel low, provided that all the symptoms are there. This diagnostic strategy might certainly be helpful for finding problems, but it is not a particularly intelligent one for finding out what is actually causing a person to feel bad.
If you ask me, much of what has made this state of affairs possible is a rivalry between psychiatrists and psychologists. Both of these professional categories have wanted to assert their own suitability as diagnosticians, rather than collaborate for the good of the patients.
Ideally, collaboration between these two professions should stretch far beyond just neuropsychiatry. Just as we needlessly perform lots of psychological tests on many of our patients with ADHD, we usually elect not to test different types of cognitive functions in other diagnostic groups. How often do we give WAIS tests to depressed adult patients where there is no specific suspicion of further neuropsychiatric issues or problems? How often do we test the executive functions or working memory of bipolar patients? And how often do we do thorough psychological examinations of conditions as complicated as schizophrenia. In my experience, almost never. Sadly, I believe that neuropsychiatric teams – in their desire to carry out comprehensive investigations – gobble up any available resources, including ones that might otherwise have been used to take advantage of the unique skillset that psychologists bring with regard to testing. This also means that there are not enough resources for other areas where psychological testing might often be needed to an even larger extent.
If we instead were to avoid one-upping one another by trying to prove which group is best at over-investigating clinical syndromes, psychological tests might be used in everyday clinical contexts where they at present typically are not. If I as a psychiatrist fail to make progress in my treatment of a depressed patient, this might for example be because the particular patient in question is unable to focus on anything at all, or form new memories. A condition that might not necessarily have been present since childhood, but which might show up on e.g. a CPT test. I might also need to get this verified without need for any additional measures. In this ideal world I would also be able to order a WAIS test or ask psychologists for advice about which tests to perform when testing for example a given patient’s episodic memory function.
What a utopia that would be! And imagine what a wonderful diagnostic reality we would have if it would also be standard procedure to complement difficult psychotherapeutic assessments with the enormous number of appropriate tests that we actually have available for determining whether therapy is likely to be successful or not. And by that I do not mean scoring scales, which really only serve to verify whether someone subjectively considers themselves to be suffering from symptoms, but objectively verifiable weaknesses that can be tested for. Today, more or less all qualified assessments are made entirely on a clinical basis. While this way of doing things mostly works well, it could be made much sharper by simply making use of additional methods that we already have available to us. But in order for this to happen, we have to shift our focus and realise that tests are not just useful tools in the specific field of neuropsychiatry, but also in the entire general field of psychiatry.