The Cardiff Depression Study: a sib-pair study of dysfunctional attitudes in depressed probands and healthy control subjects

BACKGROUND: Current cognitive theories propose that depression develops as a result of the interaction between dysfunctional cognitive schemata and environmental stressors. There is also consistent evidence of a substantial genetic contribution to depression. This study examines the familiality and stability of dysfunctional attitudes and attempts to distinguish whether they reflect trait vulnerability to depression or the state of being depressed. METHOD: The 24-item Dysfunctional Attitude Scale (DAS-24) was completed by 108 depressed probands and their nearest-aged siblings and 105 healthy control probands and their nearest-age siblings, at the time of a semi-structured clinical interview and 10-12 months later. Subjects also completed self-report measures of depressed mood on both occasions. RESULTS: Measures of clinical depression were significantly correlated with DAS scores. At retest, DAS scores remained elevated despite improvement in mood, giving support for earlier findings, that dysfunctional attitudes remain active following recovery. The dependency subscale (DAS-D) of the DAS showed modest familiality, although there were no significant differences for DAS-D scores between the two groups of siblings. In a multiple regression analysis, current mood-state was the overwhelming predictor of DAS scores. However for DAS-D, gender as well as current mood influenced scores on this subscale. CONCLUSION: Although there was modest evidence for temporal stability and familiality for some DAS-24 subscale scores, dysfunctional attitudes were predominantly influenced by current low mood, and therefore reflect the state of being depressed rather than a familial vulnerability trait underpinning depression.