Evidence of Shared Genome-Wide Additive Genetic Effects on Interpersonal Trauma Exposure and Generalized Vulnerability to Drug Dependence in a Population of Substance Users

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders

Background: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (β = -0.208, t = -2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

[Comorbidity of posttraumatic stress disorder and addiction from a biopsychosocial perspective]

Posttraumatic stress disorder and substance use disorder often co-occur within the health care system. Their comorbidity is associated with more serious acute clinical symptomatology, more frequent hospital admissions in state of emergency and significantly lower chances of improvement by psychological and pharmacological treatment. Their comorbidity contributes to dramatically unfavourable courses of illness as regards all biopsychosocial levels. The survey presented will discuss empirical findings from various perspectives: general epidemiology, substance use disorder as risk factor of trauma and PTSD, trauma and PTSD as risk factor of SUD, neurobiological effects of SUD converging towards neurobiology of PTSD, shared common factors of genetics/epigenetics, personality traits, and early developmental stress and trauma. The main focus of analysis will be put on processes that are intrinsically linked to the development and course of both disorders.

Gene-Environment Interactions in Psychiatry: Recent Evidence and Clinical Implications

PURPOSE OF REVIEW

We identify the recent evidence for gene-by-environment interaction studies in relation to psychiatric disorders. We focus on the key genotypic data as well as environmental exposures and how they interact to predict psychiatric disorders and psychiatric symptomatology. We direct our focus on the psychiatric outcomes that were focused on by the Psychiatric Genetics Consortium.

RECENT FINDINGS

Many of the studies focus on candidate gene approaches, with most of the studies drawing upon previous literature to decide the genes of interest. Other studies used a genome-wide approach. While some studies demonstrated positive replication of previous findings, replication is still an issue within gene-by-environment interaction studies. Gene-by-environment interaction research in psychiatry globally suggests some susceptibility to environmental exposures based on genotype; however, greater clarity is needed around the idea that genetic risk may not be disorder specific.

Early life experience contributes to the developmental programming of depressive-like behaviour, neuroinflammation and oxidative stress

This study used an animal model of depression induced by maternal care deprivation (MCD) to investigate whether depressive behaviour, neuroinflammation and oxidative stress were underlying factors in developmental programming after early life stress. At postnatal days (PND) 20, 30, 40, and 60, individual subsets of animals were evaluated in behavioural tests and then euthanized to assess cytokine levels and oxidative stress parameters in the prefrontal cortex (PFC), hippocampus and serum. The results showed that MCD did not induce behavioural changes at PND 30 and 40. However, at PND 20 and 60, the rats displayed a depressive-like behaviour in the forced swimming test, without changes in locomotor spontaneous activity. In the brain and serum, the levels of pro-inflammatory cytokines (interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α)) were increased, and the anti-inflammatory cytokine (interleukin-10) level was reduced throughout developmental programming (PND 20, 30, 40 and 60). Protein carbonyl levels increased in the brain at PND 30, 40 and 60. Superoxide dismutase (SOD) activity was decreased during all developmental programming phases evaluated in the brain. Catalase (CAT) activity was decreased at PND 20, 40 and 60 in the brain. Our results revealed that "critical episodes" in early life stressful events are able to induce behavioural alterations that persist into adulthood and can stimulate inflammation and oxidative damage in both central and peripheral systems, which are required for distinct patterns of resilience against psychiatric disorders later in life.