Facilitating clinical application of a dimensional model for personality disorders across the entire adult lifespan:...

The classification of personality disorders (PDs) may be enhanced by dimensional models such as the Alternative Model for Personality Disorders (AMPD) and the ICD-11. However, their implementation in clinical practice remains limited, particularly among older adults, who are underrepresented in PD research. Given that personality pathology may vary across the lifespan, incorporating an age-sensitive perspective is essential when applying dimensional models.

This study included a non-clinical sample of 754 participants aged 18 to 97 and a clinical sample of 102 older adult patients aged 65 and above. The discriminative validity of the LPFS-BF 2.0 and PID-5-BF + M was first assessed. Subsequently, age- and gender-specific normative thresholds were developed based on the non-clinical sample and evaluated within the clinical sample. Finally, self-report measures were compared with informant reports and clinical interview data (STiP-5.1) in the clinical older adult group.

Both the LPFS-BF 2.0 and PID-5-BF + M effectively differentiated between clinical and non-clinical participants. Age and gender influenced mean scores, supporting the need for adjusted normative thresholds. These thresholds successfully identified clinically elevated cases, particularly for the LPFS-BF 2.0 total score and the PID-5-BF + M domains of Negative Affectivity, Detachment, and Psychoticism. Moderate agreement was observed between self-reports, informant reports, and clinical interviews, although not all scales showed consistent correlations.

These findings highlight the importance of accounting for age and gender in the clinical application of dimensional PD models and support the use of multi-method assessment approaches.