We still lack operative and theoretically founded definitions of what a personality disorder (PD) is, as well as empirically validated and feasible instruments to measure the disorder construct. The Temperament and Character Inventory (TCI) is the only personality instrument that explicitly distinguishes personality style and disordered functioning. Here, we seek to (1) confirm in a clinical sample that the character dimensions of the TCI capture a general construct of PD across all specific PD subtypes, (2) determine whether such core features can be used to detect the presence of PD, and (3) analyze whether such detection is affected by the presence and severity of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) Axis I symptoms. Two hundred five anxious/depressed outpatients were evaluated with the Structural Clinical Interview for DSM-IV Axis I and II Disorders. Assessment also included the TCI, the Hamilton rating scales for depression and anxiety, and the Panic and Agoraphobia Scale. Sixty-one patients (29.8%) were diagnosed as having a DSM-IV PD. Self-directedness and Cooperativeness, but no other TCI dimensions, predicted the presence of PD (Nagelkerke R2 = 0.35-0.45) and had a moderate diagnostic utility (κ = 0.47-0.58) when Axis I symptoms were absent or mild. However, accuracy decreased in anxious or depressed patients. Our study supports the hypothesis of a disorder construct that is not related to the intensity of any specific PD subtype but which is common to all PDs. This construct relies largely on internal representations of the self revealing ineffectiveness and uncooperativeness. © 2008 Elsevier Inc. All rights reserved.