Mental health and substance use disorder (SUD) diagnoses may appear more forthright than they actually are. In contrast to many physical health problems, there is no way to directly and precisely measure a substance use or mental health condition to arrive at a given diagnosis.
For example, if one is trying to determine whether an individual has diabetes, that person is instructed not to eat or drink anything by mouth after midnight, and the next day blood is drawn to determine blood sugar. If the resultant fasting blood sugar level is from 100 to 125 mg/dL, the person is considered to have prediabetes. If it is 126 mg/dL or higher on two separate tests, this is a definitive finding of diabetes. This is precise and direct measurement.
Another example would be the determination of hypertension. Blood pressure is measured with an instrument called a sphygmomanometer. First, a cuff is placed around an individual’s arm and inflated with a pump until the circulation is cut off. A small valve slowly deflates the cuff, and the person measuring the blood pressure uses a stethoscope, placed on the arm, to listen for the sound of blood pulsing through the arteries. That first sound of rushing blood refers to the systolic blood pressure; once the sound fades, the second number indicates the diastolic pressure.
Blood pressure readings have two numbers, for example 140/90mm Hg. The top number is the systolic blood pressure, meaning the highest pressure when the heart beats and pushes the blood around the body. The bottom number is the diastolic blood pressure, which is the lowest pressure when the heart relaxes between beats.
Experts consider normal blood pressure to be less than 120/80 mm Hg. Blood pressure at or above these numbers are now considered prehypertensive. Blood pressure consistently at or above 140/90 is considered high blood pressure or hypertension. Hypertension diagnoses can even be staged.
Mental Health and SUD Diagnoses
Now let’s turn to mental health and SUD diagnoses. Diagnosis is a concept reached by consensus by experts in the respective areas, but such diagnoses are of questionable validity. What is schizophrenia? Schizophrenia is what people say it is! For these disorders, there is no direct measurement. How do we arrive at a diagnosis? We rely on patient self-reports, reports from others such as collaterals, observation of behavior, family history, and sometimes, psychometric testing. If ten physicians were to assess someone for hypertension or diabetes, we could be assured that they would all arrive at the same diagnosis. When compared to mental health and SUDs, we could predict a variety of different diagnoses even though they were assessing the same individual.
The lack of precision and reliability (test-retest) in psychometric testing reports is illustrated by the Supreme Court finding in a test case, Atkins, whose initial IQ score was fifty-nine, but when retested after several years in prison he scored above seventy, making him again eligible for the death penalty under Virginia law (Harris, 2013).
The lack of concreteness in mental health diagnoses is, in part, a result of social pressure. The American Psychiatric Association (APA) was begrudgingly forced to expunge homosexuality from the DSM-II and it thus it suddenly ceased to be a mental illness amid growing opposition from gay activists, and dissent within its own ranks (Drescher, 2015). This paradigm of the social nature of psychiatric diagnosis highlights the instability of the psychiatric sign: once signifying disease and perversion, homosexuality came to be recognized by the establishment as a normal variant of human sexuality. Diagnosis making is a social act—the construct of illness and disorder, “mental” or otherwise, is a social one and shifts in the concept and nature of disorder to reflect wider social, political, and economic influences.
As another example, the diagnosis of hoarding disorder first appeared in the DSM-5, where was it was previously considered a type of obsessive-compulsive disorder and not a disorder in its own right (APA, 2013). Any clinician with any degree of patient experience has come across individuals with hoarding disorder. The behavior and its symptomatology is not new. I often wonder how much effect the very popular TV show Hoarding had in the inclusion of hoarding as a new diagnosis in the DSM-5.
In the DSM-5, the diagnosis of “mental retardation” was changed to “intellectual disability,” which is a positive, less stigmatizing change in nomenclature (APA, 2013). In addition to that change, there was a change in diagnosis in which adaptive functioning was added to IQ. The result of that change was to reduce the incidence of intellectual disability, but a concomitant change was to increase the reported incidence of autism spectrum disorder (ASD) from one in five thousand in 1975 to one in sixty-eight in 2013. The change in prevalence of ASD appears to be an artifact of the change in diagnosis of intellectual disability (King & Bearman, 2009).
Image source: Sholtis, S. (2015). Increasing prevalence of autism is due, in part, to changing diagnoses. Retrieved from http://science.psu.edu/news-and-events/2015-news/Girirajan7-2015
The problems of diagnosis are also found with SUDs. The DSM-5 changed from two substance use diagnoses: “abuse” with four criteria and “dependence” with seven criteria (APA, 1994) to SUDs with eleven criteria (APA, 2013), which moves from a categorical to a continuum approach. Under the new diagnostic classification, meeting zero or one of the diagnostic criteria results in no diagnosis; meeting two or three results in a diagnosis of mild severity; meeting four or five is moderate severity, and six or more is considered severe.
Let’s look at SUDs in both the DSM-IV and DSM-5. Diagnosis is based only on the number of criteria met, with the assumption that all the criteria are equal in the weight that they lend to the diagnosis. Since there is general agreement that addiction is characterized by compulsion, loss of control, craving, and continued use in spite of adverse consequences, few if any clinicians regarded individuals with old diagnosis of abuse or meeting two or three of the eleven in the new criteria as “addicted.” Yet the diagnostic system in the DSM-5 considered a SUD of any severity as an addiction. The position that all diagnostic criteria are not equally weighted is not new and also found in both the DSM-IV and DSM-5 (APA, 1994, 2013) with the diagnosis of major depressive disorder (not changed from the DSM-IV to DSM-5). To meet diagnostic criteria for this disorder, one has to meet at least five of the nine criteria in a two-week period. However, among those five must be either or both depressed mood or loss of interest or pleasure. Clearly, the take-away message for the depressive disorder diagnosis is that all the criteria are not considered equal in weight.
The term “alcoholism” is commonly used as if it was a diagnosis, which it is not, and further, often applied to all severities of alcohol use disorder. We all know of “alcoholics” who have returned to non-problem drinking. It is my position that these folks had a mild severity of the disorder and therefore were not addicted and because of maturation—like binge-drinking college students who “graduate” out of this behavior—or because their use was the result of their inability to cope with situations which then changed or with which they developed adequate coping skills, drinking has become no longer problematic. This is further illustrated by people who can meet the same number of criteria or even the same criteria, yet in the real world have very different trajectories for their disorder.
Unless and until we can find precision in diagnosis, treatment will suffer. I see no solution to this dilemma other than possibly brain imaging or some other future, precise way of making a diagnosis that is both valid and reliable.
American Psychiatric Association (APA). (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.
American Psychiatric Association (APA). (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.
Drescher, J. (2015). Out of DSM: Depathologizing homosexuality. Behavioral Sciences, 5(4), 565–75.
Harris, J. C. (2013). New terminology for mental retardation in DSM-5 and ICD-11. Current Opinion in Psychiatry, 26(3), 260–2.
King, M., & Bearman, P. (2009). Diagnostic change and the increased prevalence of autism. International Journal of Epidemiology, 38(5), 1224–34.