Posttraumatic Major Depressive Disorder Research Articles

The gut microbiota and post-traumatic major depression disorder: insights from bidirectional two-sample Mendelian randomization.

Exposure to trauma is often associated with an increased incidence of Major Depressive Disorder (MDD), yet the mechanisms underlying MDD development post-trauma remain elusive. The microbiota-gut-brain axis has been implicated in neuropsychiatric disorders, suggesting its potential role in post-traumatic MDD (PTMDD) development. Our study aimed to assess the significance of the gut microbiome-brain interaction in PTMDD. We conducted a bidirectional two-sample Mendelian Randomization (MR) analysis to investigate the causal relationship between the gut microbiota and both PTMDD and trauma exposure in MDD. Genome-wide association study (GWAS) summary datasets for PTMDD and trauma exposure in MDD, both derived from the UK Biobank. The PTMDD dataset included 24,090 individuals (13,393 cases and 10,701 controls), while the dataset for trauma exposure in MDD comprised 22,880 participants (13,393 cases and 9,487 controls). Additionally, gut microbiota data from the MiBioGen consortium included 14,306 European individuals across 18 diverse cohorts. Our research identified a significant negative association between the phylum Verrucomicrobia (odds ratio (OR) [95% confidence interval (CI)] =0.799 [0.684-0.933], P=0.005) and the risk of developing PTMDD, suggesting a protective role for Verrucomicrobia against PTMDD. Conversely, our findings indicate no causal effects of the gut microbiota on trauma exposure in MDD. However, reverse analysis revealed that both PTMDD and MDD influence certain bacterial traits, affecting 5 and 9 bacterial traits, respectively. Moreover, Verrucomicrobia (OR [95% CI] = 1.166 [1.051 - 1.294], P=0.004) was found to be positively impacted by trauma exposure in MDD. Our findings provide a cause-and-effect relationship between the gut microbiota and PTMDD, contributing to our understanding of the microbiota-gut-brain axis and its role in neuropsychiatric disorder development after trauma. This information provides an opportunity for new treatment and prevention methods which are aimed at the gut-brain interaction.

Tobacco usage interacts with postdisaster psychopathology on circadian salivary cortisol

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) have been associated with increased rates of tobacco usage as well as with dysregulations of the hypothalamus–pituitary–adrenal (HPA) axis. At the same time tobacco also affects the HPA axis. This paper examines the relationships between PTSD, posttraumatic MDD, smoking and levels of circadian cortisol 2–3 years postdisaster. Subjects were survivors of the Enschede fireworks disaster. The sample consisted of 38 healthy survivors, 40 subjects with PTSD, and 17 subjects with posttraumatic MDD. The Composite International Diagnostic Interview was used to determine mental disorders in accordance with DSM-IV criteria. Salivary cortisol samples were collected at home immediately upon awakening, 30 min after awakening, at noon, and at 10 p.m. Quantity of smoking was measured through self-report. The results of the study show that salivary cortisol concentrations were higher in smoking subjects. Survivors with MDD following the disaster had a flatter diurnal cortisol curve than subjects with PTSD or healthy survivors. In survivors with PTSD and healthy individuals the usual dynamic pattern of increase in cortisol past awakening was present, while we did not observe this in posttraumatic MDD. These survivors with MDD tended to use more tobacco per day, and the cortisol group differences could only be revealed when we adjusted for quantity of smoking. Smoking, which may be an important palliative coping style in dealing with posttraumatic arousal symptoms, seems to mediate the relationship between traumatic stress and the HPA-axis.