Theses and Dissertations

Issuing Body

Mississippi State University


Keeley, Jared W.

Committee Member

Armstrong, Kevin J.

Committee Member

Nadorff, Michael R.

Committee Member

Winer, Eric Samuel

Date of Degree


Document Type

Dissertation - Open Access


Clinical Psychology

Degree Name

Doctor of Philosophy (Ph.D)


College of Arts and Sciences


Department of Psychology


Accuracy in applying diagnostic concepts is one of the most important aspects of any mental health professional’s work. Inaccuracy in diagnosing, or misdiagnosing, can lead to numerous problems including inappropriate and potentially harmful treatment, inaccurate prognosis, stigma, and wasted or misutilized resources. For mental health professionals, inaccuracy in diagnosing can happen both intentionally and unintentionally. The severity of a person’s symptoms or the level of functional impairment the person is experiencing are two factors which can easily confound diagnostic accuracy. The present study sought to determine how each of these factors contribute to diagnostic accuracy independently and in conjunction with one another. Participants were invited the complete the current study online and were presented with two vignettes representing varying levels of symptom severity and functional impairment severity. We asked participants to rate the severity of each (symptoms and impairment), to provide diagnostic opinions, and to provide treatment recommendations. We found that in rating the severity of symptoms or impairment, and in providing diagnoses, the presence of one (symptoms or impairment) tended to overshadow the absence of the other. However, severity ratings of either symptom or impairment severity were predictive of rates in diagnosing and recommending treatment. Additionally, we found that regardless of the presence of a diagnosis, most participants believe that the person represented in the vignette would benefit from treatment. Based on these findings, it seems when conceptualizing case vignettes, professionals may be viewing symptoms and functional impairment as more interchangeable than as different components of a diagnosis.