Assessing personality disorders using a systematic clinical interview: evaluation of an alternative to structured...

Area of Science:

• Psychiatry and Clinical Psychology
• Psychometrics and Diagnostic Assessment

Background:

• Accurate personality disorder (PD) diagnosis is challenging, often relying on self-report, which can be unreliable.
• Existing diagnostic methods may not fully capture the complexity of personality pathology.
• There is a need for reliable and valid assessment tools that minimize reliance on patient self-report.

Purpose of the Study:

• To evaluate the interrater reliability of the Shedler-Westen Assessment Procedure-200 (SWAP-200) for assessing personality pathology.
• To gather initial evidence for the validity of the SWAP-200 as an alternative diagnostic method.
• To explore the utility of quantifying clinical inference in personality diagnosis.

Main Methods:

• Two clinician-judges independently applied the SWAP-200, a 200-item Q-sort, to data from systematic clinical interviews.
• In a subset of cases, treating clinicians also used the SWAP-200 based on longitudinal knowledge, blind to interview data.
• Interrater reliability and convergent validity were assessed using correlation coefficients.

Main Results:

• Uniformly high interrater reliability was observed between interviewers (median r > .80).
• High convergent validity was found between interviewers and treating clinicians (median r > .80).
• The SWAP-200 diagnoses predicted adaptive functioning, supporting its clinical utility.

Conclusions:

• The SWAP-200 demonstrates strong preliminary reliability and validity for assessing personality pathology.
• This method offers a promising alternative to structured interviews, particularly when self-report is limited.
• Quantifying clinical inference through psychometric instruments may enhance the validity of personality disorder diagnosis.