Endocannabinoids, cortisol, and development of post-traumatic psychopathological trajectories.

OBJECTIVE: Our prior published work using the 2-factor model of PTSD identified four subgroups of trauma survivors on average 6 months following trauma: Resilient, Dysphoria, High Comorbid, and Severe Comorbid. Some findings indicate that low and high cortisol responses may increase risk for the development of PTSD and depression respectively, yet ways in which cortisol interacts with other physiological systems to enhance risk is unclear. This study examined the role of circulating eCBs in the development of previously identified psychopathological trajectories that is differentiated by cortisol in traumatically injured adults (N = 169). METHODS: Circulating concentrations of eCBs, 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA) were measured during post-injury hospitalization and on average 6 months following trauma. Differences in 2-AG and AEA among the subgroups were tested using multivariate ANCOVA. RESULTS: Dysphoria (with highest cortisol levels) and High Comorbid subgroups exhibited higher post-injury AEA compared to the Resilient group. Dysphoria subgroup showed a significant decline in AEA by 6 months compared to Resilient and High Comorbid subgroups. CONCLUSION: Change in AEA over time in individuals with high post-injury cortisol may serve as a buffer against risk for severe psychopathology. Assessing AEA and cortisol levels concurrently across time may serve as indicators of risk.

A cluster analytic approach to examining the role of cortisol in the development of post-traumatic stress and dysphoria in adult traumatic injury survivors.

Identification of specific risk factors for posttraumatic stress disorder (PTSD) versus depression after trauma has been challenging, in part due to the high comorbidity of these disorders. As exposure to trauma triggers activation of the hypothalamic-pituitary-adrenal (HPA)-axis, examining atypical stress responses via HPA-axis hormones, namely cortisol, may help in the delineation of these disorders. Indeed, extant research demonstrates that, following stress, individuals with chronic PTSD exhibit hypocortisolism (e.g., lower cortisol response than controls), while those with chronic depression exhibit hypercortisolism (e.g., higher response than controls). Less is known about the role of cortisol and these seemingly disparate profiles immediately following traumatic injury as well as whether cortisol can be used as a predictor of future development of PTSD versus depression symptoms. In this study cortisol was measured blood from 172 traumatic injury survivors during hospitalization (on average 2.5 days post-injury). PTSD and depression severity were assessed from Clinician Assessed PTSD Scale (CAPS-5) six-eight months later using a two-factor dimensional approach that measures trauma-specific symptoms of PTSD versus dysphoria (akin to depression). Cluster analysis was used to group individuals based on post-injury cortisol, PTSD, and dysphoria. Results demonstrated that trauma survivors who only developed symptoms of dysphoria at six months (with minimal symptoms of PTSD) were differentiated by high post-injury cortisol compared to other groups. By contrast, individuals who developed symptoms of both PTSD and dysphoria were differentiated by low post-injury cortisol and most severe symptoms of PTSD. Findings provide support for the presence of subgroups of trauma survivors defined, in part, by post-trauma cortisol.

To trust, or not to trust? Individual differences in physiological reactivity predict trust under acute stress.

The stress response represents an evolutionarily ancient array of biological responses to challenge or threat that facilitate survival by promoting adaptive behaviors. 'Adaptive' in the evolutionary sense, however, does not easily translate to explain stress' effect on human decisions. Much research demonstrates that acute stress alters decision-making, but outcomes are obscured by a range of methodological factors. Further, less is known about how stress affects decision-making in social contexts in which people so often act. This is of great importance in today's increasingly complex social environment, replete with potential stressors, where cooperation and trust are critical. Here the aim was to explore acute stress' effect on prosocial decision-making, while also controlling for methodological factors that may contribute to varied research outcomes. Ninety-six participants were exposed between-subjects to acute stressors with or without a significant social evaluative component, or a control procedure, after which they performed a variant of the Trust Game (a social decision-making task requiring cooperation and trust with a 'partner'). Task performance occurred at different times with respect to exposure to examine the roles of temporally distinct biological stress pathways. Overall acute stress was associated with reduced trust, but a more complex pattern emerged when accounting for individual differences in physiological stress responses via multivariate analysis. In keeping with the complexity of stress itself, acute stress may enhance or reduce propensity to trust based on an individual's unique pattern of physiological reactivity.