This study examined the utility of the Level of Personality Functioning Scale–Brief Form 2.0 (LPFS–BF 2.0) in measuring features corresponding to self–other impairment of personality functioning as defined in the new general diagnostic guidelines for Personality Disorder in DSM-5 Section III and ICD-11. A mixed clinical sample (N = 228) composed of 121 psychiatric outpatients and 107 incarcerated addicts was administered the LPFS–BF 2.0, World Health Organization Wellbeing Index (WHO–5), Symptom Checklist–90–Revised (SCL–90–R), Personality Inventory for DSM–5 (PID–5), and the Schema Mode Inventory (SMI). The LPFS–BF 2.0 yielded two latent components that correspond to an interpretation of self- and interpersonal functioning, and showed relevant associations with severity indexes, well-being, dysfunctional schema modes, and lack of healthy functioning modes. The LPFS–BF 2.0 also demonstrated incremental prediction of reduced healthy adult functioning, fulfillment, and well-being over and above the total PID–5 trait score, although this did not apply to dysregulated anger and overcompensatory coping. Taken together, the LPFS–BF 2.0 is a psychometrically satisfactory instrument that generally captures theoretically expected self–other features of personality dysfunctioning, in particular lack of healthy functioning and fulfillment but to a lesser degree overcompensatory and antagonistic features. Findings warrant replication in different clinical and forensic populations.