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The Myth of Mental Health Diagnosis

Disagreement between clinicians is the norm, not the exception.

Key points

  • Trained psychiatrists who independently evaluated an individual agreed that they had depression only 4 to 15 percent of the time.
  • This lack of consistency becomes understandable when we compare the symptoms of anxiety and depressive disorders.
  • Two clinicians may look at the same symptoms but see and name them differently based on the context.
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How much is art and how much is science?
Source: Photo by Matheus Viana on Pexels

In the lead-up to the release of the Diagnostic and Statistical Manual of Mental Disorder, Fifth Edition (DSM-5) in 2013, field trials were conducted in real-world settings to essentially see how useful this bible for mental health clinicians was in producing valid, reliable diagnoses.

For each major mental health diagnosis (e.g., schizophrenia, PTSD, alcohol use disorder, etc.), a score was calculated for inter-rater reliability—how much two clinicians agree with one another that a person has a certain diagnosis.

You would think it would be fairly obvious if someone is depressed, right? Wrong. Highly trained psychiatrists who independently evaluated an individual could only agree that the person had depression between 4 and 15 percent of the time.1.

The inter-rater reliability score also fell in this 'questionable' range of 4 to 5 percent (the possible ranges being 'very good,' 'good,' 'questionable,' and 'unacceptable') for diagnoses of generalized anxiety disorder, mild traumatic brain injury, and antisocial personality disorder.2

Let's think about this: Based on these findings, if you are diagnosed with depression by a clinician using the DSM-5, there is an 85 to 96 percent chance that if you went to a second clinician, they might not diagnose you with depression (with a 4 to 15 percent chance that they would).

One reason for clinicians' striking lack of consistency can be understood by comparing anxiety and depressive disorders. Historically, we have treated anxiety and depression as two distinct disorders. The DSM, most recently revised in March 2022 and released as the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), defines generalized anxiety disorder (GAD) as "excessive anxiety and worry (apprehensive expectation), occurring more days than not for at least six months, about several events or activities (such as work or school performance)."3

According to the DSM-5-TR, to meet the criteria for major depressive disorder (MDD), "five (or more) of the following [nine] symptoms [must] have been present during the same two-week period and represent a change from previous functioning; at least one of the symptoms is either (1) depressed mood or (2) loss of interest or pleasure." Four of these symptoms refer to difficulty concentrating, difficulty sleeping, being easily fatigued, and changes in psychomotor movement. Interestingly, these symptoms that are criteria for diagnosing MDD are also criteria for diagnosing GAD.

As you can guess, this overlap in symptoms has led to high comorbidity between GAD and MDD, meaning that many people diagnosed with one condition are also diagnosed with the other. For example, a worldwide survey found that 45.7 percent of individuals with lifetime major depressive disorder also reported a lifetime history of one or more anxiety disorders.

Almost half of people with depression say they also have anxiety. Other studies have found comorbidity rates between GAD and MDD ranging from 40 to 98 percent. High comorbidity rates are not confined to correlations between GAD and MDD but can be found between many DSM diagnoses.

All of this is to say that perhaps we should take mental health diagnoses with a grain of salt. You may get one diagnosis from one clinician and find that if you go to another one, you may get a different one—or a few extra ones. Some clinicians might tend to diagnose people more often with depression, while other clinicians might be more likely to diagnose people with anxiety.6

This does not mean that diagnoses are completely useless, but it does mean we should treat them less literally and understand that two clinicians may be looking at the same symptoms but seeing and naming them differently based on different contexts, which can include the clinician's own biases, differences in training, and what the client chooses to report.

You may see a product in a bakery window during breakfast time and call it a muffin, and I might see a similar product with frosting on it at a birthday party and call it a cupcake. Let's realize that our perceptions are subjective and that there can be multiple truths. Let's treat our diagnoses as descriptions and not explanations.


1. Lieblich, S., Castle, D., Pantelis, C., Hopwood, M., Young, A., & Everall, I. (2015). High heterogeneity and low reliability in the diagnosis of major depression will impair the development of new drugs. BJPsych Open, 1(2), E5-E7. doi:10.1192/bjpo.bp.115.000786

2. Regier, D. A., Narrow, W. E., Clarke, D. E., Kraemer, H. C., Kuramoto, S. J., Kuhl, E. A., & Kupfer, D. J. (2013). DSM-5 field trials in the United States and Canada, Part II: test-retest reliability of selected categorical diagnoses. American journal of psychiatry, 170(1), 59-70.

3. Facts & Statistics: Anxiety and Depression Association of America, ADAA. Facts & Statistics | Anxiety and Depression Association of America, ADAA. (n.d.). Retrieved June 24, 2022, from

4. Centers for Disease Control and Prevention. (2022, March 25). FastStats - depression. Centers for Disease Control and Prevention. Retrieved June 24, 2022, from

5. American Psychiatric Association Publishing. (2022). Diagnostic and statistical manual of mental disorders: Dsm-5-Tr.

6. Kahneman, D., Sibony, O., & Sunstein, C. R. (2022). Noise (pp. 38-46). HarperCollins UK.