The agreement between clients' and their therapists' ratings of personality disorder traits.

Objective: Treating clinicians provide the majority of mental health diagnoses, yet little is known about the validity of their routine diagnoses, including the agreement with clients' self-reports. This is particularly notable for personality disorders (PDs) as the literature suggests weak agreement between therapists and clients. Existing research has been limited by a focus on PD categories and brief therapist-report measures. Furthermore, although self-reports of PD have been criticized for underreporting, very few data have compared them with therapist report in terms of mean level.

Method: We addressed these limitations by collecting dimensional trait ratings from 54 therapist-client dyads within outpatient clinics. The clients (52% women, 94% Caucasian, 39.8 years) provided ratings of dimensional PD traits via the Personality Inventory for DSM-5 (PID-5) while therapists (72% female, 89% Caucasian) completed the Informant version of the same measure.

Results: Employing systematic measures of traits yielded higher rank-order agreement than observed in prior studies, with a median correlation of .41 across the PID-5 domains. Most interestingly, mean-level comparisons indicated that clients reported significantly higher levels of PD pathology than did their therapists. This effect was most notable for the domain of Psychoticism, which had the lowest rank-order agreement (r = .16) and the largest mean-level discrepancies.

Conclusions: When clinicians utilized systematic measures of dimensional traits their agreement with client was higher than reported in past studies. Furthermore, clients reported significantly more PD pathology than was noted by their therapists suggesting concerns about invalid self-reports due to underreporting have been overstated. (PsycINFO Database Record