Habituation and cortisol dysregulation in depression.

The relationship between hypothalamic-pituitary-adrenal (HPA) dysregulation and skin conductance measures of habituation, stimulus specificity, and dishabituation was investigated in psychiatric patients exhibiting depressed affect. As a group, depressed patients showed a relative failure to dishabituate when compared with control subjects. Nonsuppression of cortisol following dexamethasone was associated with decreased response specificity as reflected in direct response measures and baseline skin conductance level. The impairment of response specificity to a novel stimulus is consistent with previous studies demonstrating a role for cortisol in the regulation of selective attention processes.