The General Assessment of Personality Disorder (GAPD) as an instrument for assessing the core features of personality disorders

This study presents a psychometric evaluation of the General Assessment of Personality Disorder (GAPD), a self-report questionnaire for assessing the core components of personality dysfunction on the basis of Livesley's (2003) adaptive failure model. Analysis of samples from a general (n = 196) and a clinical population (n = 280) from Canada and the Netherlands, respectively, found a very similar two-component structure consistent with the two core components of personality dysfunction proposed by the model, namely, self-pathology and interpersonal dysfunction. Moreover, the GAPD discriminated between patients diagnosed with and without Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR) personality disorder(s) and demonstrated discriminative power in detecting the severity of personality pathology. Correlations with a DSM-IV symptom measure and a pathological traits model suggest partial conceptual overlap. Although further testing is indicated, the present findings suggest the GAPD is suitable for assessing the core components of personality dysfunction. It may contribute to a two-step integrated assessment of personality pathology that assesses both personality dysfunction and personality traits.

The core features of personality disorder can be defined as disorders in the self and in the capacity for interpersonal functioning. A clinically useful operationalization of disordered functioning of personality is needed to determine the maladaptivity of personality traits. An integrated assessment of personality (dys)functioning and personality traits provides a more comprehensive clinical picture of the patient, which may aid treatment planning.