Overdiagnosis and underdiagnosis of personality disorders in older adults

Abstract

Objective: Recent evidence suggests that some of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition personality disorder (PD) criteria contain measurement bias across age groups. Specifically, this research showed that younger and older adults were differentially likely to endorse certain PD criteria, even when both groups were statistically matched using mechanisms of item response theory (IRT) for degree of PD pathology. For the analyses presented here, the authors used data from a large epidemiological study (N = 43,093), the National Epidemiologic Survey on Alcohol and Related Conditions, to examine the influence of this item-level measurement bias for reaching accurate algorithmic PD diagnoses of older adults.

Methods: Joint probability analyses were used to determine the net effect of the item-level bias on the possible over- or underdiagnosis of six PDs in older adults.

Results: When older adults were compared to younger adults at equivalent levels of PD pathology, they were more likely to receive diagnoses of obsessive-compulsive and schizoid PDs. In contrast, they were less likely to receive diagnoses of avoidant and dependent PDs. Younger and older adults were equally likely to receive diagnoses of histrionic and paranoid PDs. Of the seven PDs assessed in this dataset, only these six lend themselves to this type of analysis; antisocial PD differs because a diagnosis depends upon the presence of conduct disorder.

Conclusion: These findings raise concerns regarding the interpretation of existing older adult PD prevalence data.

Figure 1. An Illustration of aDIF and bDIF

Figure 2. Item Characteristic Curves for Schizoid PD Across Younger and Older Age Groups