اختلال افسردگی اساسی، اختلال اضطراب فراگیر و همبودی آن: ارتباط با کورتیزول در مطالعه تجربه ویتنام

Objectives The aim of these analyses was to examine the association of cortisol, dehydroepiandrosterone sulphate (DHEAS), and the cortisol:DHEAS ratio with the diagnoses of major depressive disorder (MDD), generalised anxiety disorder (GAD), and their comorbidity. Design This was a cross-sectional study. Methods Participants were 4256 Vietnam era US army veterans. From military service files, telephone interviews, and a medical examination, occupational, socio-demographic, and health data were collected. One-year prevalence of MDD and GAD was determined through a diagnostic interview schedule based on the DSM-IV criteria. Contemporary morning fasted cortisol and DHEAS concentrations were determined. Analyses of covariance were run, first with adjustment for age and then additionally adjusting for a range of candidate confounders. Results In fully adjusted analyses, there was evidence of lower basal cortisol levels in individuals with MDD and co-morbid MDD and GAD than those with GAD alone or no diagnosis. Conclusion This suggests that MDD and its comorbidity can also be characterised by low as well as high cortisol levels. A profitable line of future research might be to examine cortisol and DHEAS levels in more representative samples including older participants and women with and without MDD, GAD, and other psychiatric diagnoses.

Mental health disorders in the general population are common (Kessler et al., 2005a and Kessler et al., 2005b). In fact, an estimated 14% of the global disease burden has been attributed to such conditions as depression and anxiety (World Health Organisation, 1992–1994). This is likely to be an underestimate of the true burden of mental health problems as it fails to take into consideration that mental health increases the risk of other health conditions such as communicable and non-communicable diseases, and injuries (Prince et al., 2007). Populations who have been exposed to traumatic events, such as war veterans, have an even higher prevalence of major mental health problems, particularly depressive disorder (MDD) and generalised anxiety disorder (GAD) (Reeves et al., 2005, Gaylord, 2006 and Hoge et al., 2006). For example, soldiers assessed a few months after returning from deployment to Afghanistan and Iraq had a GAD prevalence of around 14% and 15%, respectively, and prevalence of MDD of around 17% and 16% (Hoge et al., 2004). As yet, the aetiology of depression and anxiety are not fully understood, although it is generally accepted that chronic exposure to stressful life events has an important role (Thomson and Craighead, 2008).