Overdiagnosis in Mental Health

Here on our blog, we have previously discussed the problems associated with misdiagnosis and/or underdiagnosis of mental health problems. However, we have not spent much time discussing the related topic of overdiagnosis. In an article published in the journal Psychotherapy and Psychosomatics, titled Defining and Evaluating Overdiagnosis in Mental Health: a Meta-Research Review, authors Thombs, Turner, and Shrier systematically examined the use of the term “overdiagnosis” in the mental health literature, and how this definition (or lack thereof) impacts our ability to glean meaningful information about this highly discussed topic.

What did they do?

The authors of this article highlight two primary objectives. First, they aimed to describe how the term “overdiagnosis” in mental health has been used and/or defined in the existing literature. Second, they aimed to identify examples of previous attempts to quantify overdiagnosis.

Why did they do it?

Overdiagnosis is a problem across many domains of health, and the field of mental health is certainly not immune. There is a serious challenge, however, when trying to differentiate the term overdiagnosis from other similar, yet categorically different terms, such as misdiagnosis. While the difference in nomenclature might appear to be somewhat an issue of semantics, variability and difficulty distinguishing between these terms (i.e., variability in how these things are operationally defined) in fact changes the conclusions that we are able to draw regarding problems like overdiagnosis that are often scrutinized in our field. Without a standard definition for the term overdiagnosis, clear and accurate conclusions regarding true rates of overdiagnosis, across any disorder, will continue to be at question.

How did they do it?

The authors included studies that incorporated overdiagnosis as a main theme of the article. Overall,164 articles were included in the review. Within all 164 articles, the authors classified both explicit and implicit definitions of “overdiagnosis” that were either consistent or inconsistent with the two part framework described by Brodersen and colleagues.

What did they find?

Generally speaking, there were very few examples in the existing literature where the term overdiagnosis was used in a way that was consistent with the intended meaning. Overdiagnosis, regardless of the exact definition provided by authors of included studies, was the main focus of 90 articles (54.9%), was addressed but was not the main focus of 48 articles (29.3%), and was mentioned but not the focus of 26 articles (15.9%). Overall, 9 articles (5.5%) explicitly defined overdiagnosis and 155 (94.5%) used an implicit definition. Of all the uses of the term overdiagnosis, only 22 (11%) were consistent with the intended meaning of the word. Approximately 80% of the time overdiagnosis was used, authors were referring to the term misdiagnosis and approximately 3% were referring to false-positive test results. The remainder of misuses (9%) were too vague to categorize.

Regarding the second objective of this review, the authors found that none of the included articles clearly quantified overdiagnosis based on overdetection or overdefinition.

What does it all mean (our take)?

Terminology within the scientific literature is critical as it directly corresponds to the way that findings are interpreted. What the authors of this interesting review study have identified is a serious problem that is impacting our ability to understand the problem of overdiagnosis in mental health - and that problem is that there is a lack of consistent definition of the term across researchers and providers. This variability leads to measuring one thing (e.g., misdiagnosis - a broad term) and labeling it as another (e.g., overdiagnosis - a more specific term).

So how do we change this? An agreed upon standard definition of the term overdiagnosis (and other diagnostically relevant terms) would do the trick...though, this is much easier said than done. More studies like the study we reviewed today are crucial in helping to further evaluate some of the ongoing terminology problems in our field, and thus helping to point us in the direction of future change.