Valid self-report assessment of psychopathology relies on accurate and credible responses to test questions. There are some individuals who, in certain assessment contexts, cannot or choose not to answer in a manner typically representative of their traits or symptoms. This is referred to, most broadly, as test response bias. In this investigation, we explore the effect of response bias on the Personality Inventory for DSM-5 (PID-5; Krueger, Derringer, Markon, Watson, & Skodol, 2013 ), a self-report instrument designed to assess the pathological personality traits used to inform diagnosis of the personality disorders in Section III of DSM-5. A set of Minnesota Multiphasic Personality Inventory Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008 / 2011 ) validity scales, which are used to assess and identify response bias, were employed to identify individuals who engaged in either noncredible overreporting (OR) or underreporting (UR), or who were deemed to be reporting or responding to the items in a "credible" manner-credible responding (CR). A total of 2,022 research participants (1,587 students, 435 psychiatric patients) completed the MMPI-2-RF and PID-5; following protocol screening, these participants were classified into OR, UR, or CR response groups based on MMPI-2-RF validity scale scores. Groups of students and patients in the OR group scored significantly higher on the PID-5 than those students and patients in the CR group, whereas those in the UR group scored significantly lower than those in the CR group. Although future research is needed to explore the effects of response bias on the PID-5, results from this investigation provide initial evidence suggesting that response bias influences scale elevations on this instrument.

Objective: Despite evidence of significant symptom heterogeneity and excessive diagnostic comorbidity, many contend that borderline personality disorder (BPD) is unidimensional, an assumption that rests primarily on results from factor analytic investigations of BPD symptom criteria. We note several limitations in the literature and argue that the symptom structure of BPD can be best clarified by using both factor analytic techniques and examining the BPD symptom dimensions in relation to external criteria (that is, personality traits). Our goals were to: examine if the symptoms of BPD are best conceptualized as unidimensional or multidimensional, and determine the extent to which personality traits account for any symptom dimensions that underlie BPD. Method:All published structural models of the BPD symptom criteria were identified and tested for statistical fit using confirmatory factor analysis in a sample of 373 patients who had completed the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders-Axis II Personality Questionnaire BPD scale. Dimensions from the best fitting model were examined in relation to traits from the Five-Factor Model (FFM) and the Personality Psychopathology Five (PSY-5) using correlational and regression analyses.Results: Sanislow's 3-factor model, containing affect dysregulation, behavioural dysregulation, and disturbed relations symptom dimensions, provided the best fit; the unidimensional model produced the worst. The symptom dimensions of the 3-factor model were differentiable from one another and had unique associations with the FFM and PSY-5 personality traits.