The Personality Structure Questionnaire (PSQ): a cross-validation with a large clinical sample.

Area of Science:

• Psychology
• Clinical Psychology
• Psychometrics

Background:

• The Personality Structure Questionnaire (PSQ) is used to assess psychological health.
• Validating psychometric instruments is crucial for accurate patient assessment in clinical settings.

Purpose of the Study:

• To evaluate the psychometric properties of the Personality Structure Questionnaire (PSQ) in a large sample of adult National Health Service (NHS) patients.
• To assess the stability of PSQ scores during waiting periods and their change following psychological therapy.

Main Methods:

• Maximum likelihood and principal component analyses were used to assess the unidimensionality of the PSQ.
• Cronbach's alpha was calculated to determine internal consistency.
• Convergent and discriminant validity were examined through correlations with other psychological tests and clinician ratings.

Main Results:

• The PSQ items formed a unidimensional scale, meeting criteria for maximum likelihood, principal component analyses, and Cronbach's alpha.
• PSQ scores showed a small negative association with age and no significant sex difference.
• Scores remained stable during the waiting list period but significantly decreased after a median of 15 weeks of therapy.
• Intercorrelations between the PSQ's sub-concept clusters were sizeable and statistically significant.

Conclusions:

• The PSQ is a psychometrically sound, unidimensional measure suitable for assessing psychological health in NHS patients.
• Therapy is effective in reducing psychological pathology as measured by the PSQ.
• Further refinements to the PSQ may enhance its utility in clinical practice.