Personality and Psychotic-Like Features in Post-Traumatic Stress Disorder With Severe Depression: An Minnesota Multiphasic Personality Inventory-2 Schizophrenia Scale Analysis

OBJECTIVE: We aimed to identify factors influencing the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Schizophrenia scale (T_Sc) among patients with post-traumatic stress disorder (PTSD) who underwent both Clinician Administered PTSD Scales (CAPS) and MMPI-2. METHODS: We retrospectively reviewed 119 patients who underwent CAPS and MMPI-2 from May 2013 to November 2022 at Veteran Health Service Medical Center, Seoul, Korea. Based on the Korean-Beck Depression Inventory-II (K-BDI-II), the PTSD patients (n=64) were classified into severe depression group (K-BDI-II ≥29; n=43) and less-severe depression group (K-BDI-II <29; n=21). Correlations among K-BDI-II, CAPS, and MMPI-2 scales were examined, and multiple linear regression analyses were performed to identify predictors of T_Sc after adjusting for potential confounders (e.g., age, sex, CAPS scores, MMPI-2 scales). RESULTS: The severe depression group had significantly higher T_Sc scores (p<0.001). T_Sc was strongly correlated with K-BDI-II scores (r=0.70, p<0.001). In regression analysis, PTSD patients with severe depression (K-BDI-II ≥29) showed higher T_Sc than those without severe depression after adjustment for age, sex, and CAPS; however, this association was attenuated after further adjustment for additional covariates. Multiple linear regression analyses revealed that MMPI-2 restructured clinical (RC) scales, -particularly Demoralization was associated with T_Sc score. CONCLUSION: PTSD patients frequently exhibit elevated T_Sc scores, particularly when severe depression coexists. However, the independent contribution of depression diminishes when underlying personality and psychopathological traits including demoralization are considered. These findings highlight the necessity of individualized MMPI-2 interpretation and tailored clinical strategies for this subgroup.