Plasma cortisol levels and resilience in depressed patients

Introduction: In recent years a large body of evidence has emerged linking stressful life events with an increased vulnerability for affective and anxiety disorders. Stressful events often precede the onset of depression and stress has also been associated with the severity of the illness. Meantime there has been growing interest in the concept of resilience. A current theory views resilience as a measure of stress coping ability and its clinical significance may lie in its ability to function as an index of overall mental health. Resilience is a complex notion that incorporates such dimensions as coping mechanism and personality. Several critical factors are associated with a successful adaptation to stressful events: some of these include temperament, personality traits, cognitive factors, genetic traits, and other attribute, such a sense of humour and social support. Existing literature highlights a correlation between PTSD and low resilience. Furthermore, resilience can be used as a measure of treatment outcome in patients suffering of post-traumatic stress. Regarding mood disorders there is a lack of information on the correlation between resilience and treatment outcome. An analysis of the biological mechanisms underlying both resilience and depression shows the implication of common features. Several biochemical mediators of response to extreme stress may be related to resilience or vulnerability, and the release of cortisol may tend to undermine resilience. The present study analyses the correlation between resilience and plasma cortisol levels in depressed patients during treatment. Methods: 38 outpatients (M/F = 13/25; mean age 43.09±15.01) with a Major Depressive Disorder (MDD) during a Major Depressive Episode (MDE) have been recruited at the Institute of Psychiatry of the Catholic University in Rome. Acute symptoms were measured with 21-HDRS (Hamilton Depression Rating Scale) and HARS (Hamilton Anxiety Rating Scale); CD-RISC (Connor-Davidson Resilience Scale) was used to measure resilience. A blood sample for the determination of plasma cortisol levels was collected. Psychopathological status and laboratory testing were assessed before the admission and after 12 weeks. Results: No significant correlation between plasma cortisol levels and HDRS, HARS or resilience scores at the baseline has been found in depressed patients. A significant inverse correlation between resilience scores and severity of symptoms has been observed (r = -0.428, p = 0.01). A significant decrease of plasma cortisol levels has been observed after antidepressant treatment (173.10±68.43 vs. 126.83±49.90, p = 0.014). A higher remission rate was observed among the patients having a better resilience. Conclusions: Recent studies are trying to determine which neurobiological responses are related to resilience, to psychological stress in general and in specific psychopathological forms. More specifically, the hyperactivity of the hypothalamic–pituitary–adrenal axis is a frequent finding in depressed patients. This same alteration has been correlated to a weak stress response and therefore to a low resilience. In our small sample plasma cortisol levels did not provide significant correlation to resilience scores. Nevertheless resilience seems to be inversely related to the severity of depressive episode and could offer a predictive value for treatment outcome.