BDNF serum levels in subjects developing or not post-traumatic stress disorder after trauma exposure

Post-traumatic stress disorder (PTSD) is a syndrome resulting from exposure to a severe traumatic event that poses threatened death or injury and produces intense fear and helplessness. The neural structures implicated in PTSD development belong to the limbic system, an important region for emotional processing. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that serves as survival factor for selected populations of central nervous system (CNS) neurons and plays a role in the limbic system by regulating synaptic plasticity, memory processes and behavior. Impaired BDNF production in the brain can lead to a variety of CNS dysfunctions including symptoms associated with PTSD. However, so far fewer studies have investigated this neurotrophin in patients with PTSD. Furthermore, given the multiple role of BDNF in various CNS disorders, it cannot be excluded that traumatic events per se may influence neurotrophin levels, without a direct association to the PTSD syndrome.     

Refining the psychometric properties of the circadian type inventory

The psychometric properties of the 18-item circadian type inventory (CTI) were examined in a non-shiftwork sample. Inter-item correlations for each scale were low to moderate. Confirmatory factor analysis (CFA) via structural equation modelling did not support the posited structure of the CTI. Principal components analysis and reliability analyses suggested the CTI is better represented by 11-items. The revised five item FR scale accounted for 27% of the variance, had stronger factor loadings and increased Cronbach alpha. The psychometric properties of the six item LV scale were marginally improved and explained 21% of the variance. The two-factor 11-item model was supported by CFA. Compared to the 18-item model, the 11-item model showed a marked improvement on several incremental fit indices and achieved a more parsimonious model fit. There was some indication of gender differences but a multi-group CFA indicated model parsimony was best for the invariant model. Gender difference needs to be further examined in large samples using a similar gender balance. It is concluded that the 11-item CTI is psychometrically superior to the original. However, its predictive efficacy needs to be examined in longitudinal studies.