Abstract
The purpose of these three studies was to conduct an initial investigation into Beck, Freeman, and Associates' (1990) cognitive theory of personality disorders in an undergraduate population of personality disorder analogues. In Study 1, preliminary support for the reliability and validity of a measure of the dysfunctional thought patterns (i.e. Thoughts Questionnaire) was gathered. In Studies 2 and 3, specific dysfunctional thought patterns, as proposed by Beck et al. (1990), were found to correlate with corresponding SCID-II personality disorder scales. However, many thought patterns lacked specificity to their corresponding personality disorder, with thought pattern scores being intercorrelated. These results are consistent with those of other published studies, using both university analogue and clinical outpatient samples.
Conclusions
The present three studies have some obvious limitations, namely, the use of university student samples, even though these students had assessed personality disorder features, and the low number of students meeting criteria for particular personality disorder categories. Nonetheless, these studies make a contribution as preliminary tests of Beck et al.'s hypotheses (1990) that specific dysfunctional thoughts are associated with specific personality disorders, hypotheses that have since been investigated in other published research.
The psychometric properties of both the Personal Beliefs Questionnaire and the Thoughts Questionnaire appear to be good, based on the present Study 1, another study with university student participants (Trull et al., 1993), and a study with a clinical outpatient sample (Beck et al., 2001). These two highly similar questionnaires display very good internal consistency and test re-test reliability, and modest concurrent validity with other related scales. In conclusion, the PBQ has good established psychometric properties, especially temporal and internal reliability, and can be used in future research. The TQ most likely will not be used in future research, but the psychometric data presented here in Study 1 is supportive of the use of the PBQ.
The overlap among thought clusters shown by individuals with different personality disorders, however, suggests that further research is needed on the discriminant validity of both the PBQ and the TQ. In the meantime, this overlap indicates that neither the PBQ nor the TQ is useful in formulating a diagnosis of a specific personality disorder to be assigned to a given client. Either measure, however, would be useful in indicating specific thoughts or thought patterns that might be the focus of cognitive therapy with that particular individual. Indeed, suggestions made to apply cognitive therapy to the treatment of personality disorders (Beck et al., 1990) have been successfully integrated with cognitive therapy for depression (Beck, Rush, Shaw, & Emery, 1979) to modify both depression and personality disorders (Kuyken et al., 2001 and Nelson-Gray et al., 1996), with the PBQ being used to identify dysfunctional thought patterns by Kuyken et al. (2001).
