A Comparison of Dimensional and Categorical Approaches to Characterizing the Association Between Posttraumatic Stress Disorder and Future Suicide Attempts

Abstract

The present study compared the utility of categorical (i.e., diagnostic status) and dimensional (i.e., symptom severity) approaches to measuring posttraumatic stress disorder (PTSD) in predicting future suicide attempts among participants in a nationwide, longitudinal study of U.S. military veterans who were deployed in support of operations in Iraq or Afghanistan after the September 11, 2001, terrorist attacks (9/11) and were enrolled in Veterans Health Administration services (N = 1,649). Following an initial assessment of PTSD symptoms, we assessed for suicide attempts at two subsequent time points (M = 28.74 months, SD = 8.72 and M = 55.11 months, SD = 6.89 following the initial assessment). Between the initial and final assessments, 125 participants (7.58%) made at least one suicide attempt. All categorical and dimensional indicators of PTSD predicted suicide attempts at both time points except the categorical indicator for reexperiencing symptoms. Categorical indicators predicting suicide attempts demonstrated excellent sensitivity but poor specificity and overall accuracy. The point along the continuum at which PTSD symptom severity was most accurate regarding the prediction of future suicide attempts was well above the threshold previously established as indicating a probable diagnosis. Although this score was less sensitive than diagnostic indicators, it demonstrated greater specificity and overall accuracy in predicting future suicide attempts. The present results indicate that veterans whose PTSD symptoms satisfy the diagnostic criteria have a higher risk of future suicide attempts, but this risk appears to be even higher for veterans with symptom levels above the diagnostic threshold.

Introduction to the Special Issue on Posttraumatic Stress and Suicide

“…These results also are in keeping with the movement to investigate distinctions related to the patterns of specific PTSD symptom clusters individuals endorse (Kerig, 2019). For example, Lee et al (2021) found that meeting the diagnostic criteria for the intrusions (termed "reexperiencing" in DSM-IV parlance) cluster was the least accurate indicator of suicide risk. Future studies that "unpack" this phenomenon and more directly examine the specific associations between suicide and the other symptom clusters-namely avoidance, NACM, and arousal-will be of interest.…”

“…Segueing into critical issues regarding methodology, the next article in the special issue compares the utility of dimensional (i.e., diagnostic status) versus categorical (i.e., symptom severity) approaches to measuring PTSD in the context of predicting suicide attempts among military personnel (Lee et al, 2021). A key finding of the study is that diagnostic status served as a sensitive but not a specific nor accurate predictor of suicide attempts at two subsequent time points among the 125 participants in the study who engaged in such behavior.…”

Association between post-traumatic stress disorder severity and death by suicide in US military veterans: retrospective cohort study

“…6 Compared with studies that analysed PTSD symptom severity, the results of this study are consistent with those of both Cooper et al, who found that positive PC-PTSD screening results were associated with an increased suicide mortality risk, 15 and Lee et al, who found that the risk of suicide attempts was higher for veterans with PTSD symptom levels above the diagnostic threshold. 18…”

“…18 Veterans whose PTSD symptoms satisfied the diagnostic criteria had a higher risk of future suicide attempts, but the risk was even higher for veterans with symptom levels above the diagnostic threshold. 18 This study underscores the importance of using diagnostic codes in conjunction with PTSD symptom severity assessments as potential indicators of suicide risk. However, the study did not use suicide mortality as a primary outcome and the sample ( n = 1649) was too small to accurately evaluate suicide risk.…”

“…symptom severity) approaches to measuring PTSD in predicting future suicide attempts among post-9/11 veterans. 18 Veterans whose PTSD symptoms satisfied the diagnostic criteria had a higher risk of future suicide attempts, but the risk was even higher for veterans with symptom levels above the diagnostic threshold. 18 This study underscores the importance of using diagnostic codes in conjunction with PTSD symptom severity assessments as potential indicators of suicide risk.…”