Childhood stressful events, HPA axis and anxiety disorders

Associations between psychiatric symptoms and cortisol levels in Nicaraguan young school-age children

The regulation of the Hypothalamus-Pituitary-Adrenal axis (HPA-axis) with its end product cortisol seems to be affected in several psychiatric disorders. Although findings are not conclusive, internalizing symptoms have primarily been associated with higher diurnal cortisol levels and externalizing symptoms with lower cortisol levels. In this study on nine-year-olds in Nicaragua (n=111), we investigated associations between child psychiatric symptoms, using the Child Behavior Check List (CBCL), and saliva cortisol levels collected in the morning and afternoon, also adjusting for potential confounders. In line with previous findings, internalizing symptoms were significantly associated with higher morning, but not afternoon cortisol levels. Surprisingly, externalizing symptoms were also significantly associated with higher morning cortisol levels. Possibly, this association between externalizing symptoms and cortisol levels may be characteristic of early ages, representing a higher exposure to external stressors. The study highlights the need for prospective studies, following the development of the HPA-axis and its association with psychiatric symptoms.

Exposure to mobile phone electromagnetic field radiation, ringtone and vibration affects anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats

Research on the effects of Mobile phone radio frequency emissions on biological systems has been focused on noise and vibrations as auditory stressors. This study investigated the potential effects of exposure to mobile phone electromagnetic field radiation, ringtone and vibration on anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats. Twenty five male wistar rats were randomly divided into five groups of 5 animals each: group I: exposed to mobile phone in switched off mode (control), group II: exposed to mobile phone in silent mode, group III: exposed to mobile phone in vibration mode, group IV: exposed to mobile phone in ringtone mode, group V: exposed to mobile phone in vibration and ringtone mode. The animals in group II to V were exposed to 10 min call (30 missed calls for 20 s each) per day for 4 weeks. Neurobehavioural studies for assessing anxiety were carried out 24 h after the last exposure and the animals were sacrificed. Brain samples were collected for biochemical evaluation immediately. Results obtained showed a significant decrease (P < 0.05) in open arm duration in all the experimental groups when compared to the control. A significant decrease (P < 0.05) was also observed in catalase activity in group IV and V when compared to the control. In conclusion, the results of the present study indicates that 4 weeks exposure to electromagnetic radiation, vibration, ringtone or both produced a significant effect on anxiety-like behavior and oxidative stress in young wistar rats.

Brain-gut-microbiota axis: challenges for translation in psychiatry

PURPOSE

The accruing data linking the gut microbiome to the development and function of the central nervous system has been proposed as a paradigm shift in neuroscience. The gut microbiota can communicate with the brain via neuroimmune, neuroendocrine, and neural pathways comprising the brain-gut-microbiota axis. Dysfunctional neuroimmune pathways are implicated in stress-related psychiatric disorders.

METHODS

Using depression as our primary example, we review both the preclinical and clinical evidence supporting the possible role played by the gut microbiota in stress-related psychiatric disorders. We consider how this can inform future treatment strategies and outline the challenges and necessary studies for moving the field forward.

RESULTS

The role played by the gut microbiota has not been fully elucidated in psychiatric populations. Although tempting to speculate that psychiatric patients may benefit from therapeutic modulation of the brain-gut-microbiota axis, the translational applications of the results obtained in rodent studies have yet to be demonstrated.

CONCLUSIONS

Evidence of altered gut microbiota composition and function in psychiatric patients is limited and cannot be regarded as proven. Moreover the efficacy of targeting the gut microbiota has not yet been established, and needs further investigation.

DISTINCT ETIOLOGICAL INFLUENCES ON OBSESSIVE-COMPULSIVE SYMPTOM DIMENSIONS: A MULTIVARIATE TWIN STUDY

BACKGROUND

Obsessive-compulsive disorder (OCD) is characterized by five major dimensions, including contamination/washing, harm/checking, symmetry/ordering, hoarding, and forbidden thoughts. How these dimensions may relate etiologically to the symptoms of other obsessive-compulsive related disorders (OCRDs) and anxiety disorders (ADs) is not well known. The aim of this study was to examine the genetic and environmental overlap between each major obsessive-compulsive dimension with the symptoms of other OCRDs and ADs.

METHODS

Two thousand four hundred ninety-five twins of both sexes, aged between 18 and 45 years, were recruited from the Australian Twin Registry. Measures used scores on four dimensions (obsessing (forbidden thoughts), washing, checking, and ordering) of the Obsessive-Compulsive Inventory-Revised, Dysmorphic Concerns Questionnaire, Hoarding Rating Scale, Anxiety Sensitivity Index, Social Phobia Inventory, and Stress subscale of the Depression, Anxiety, and Stress Scale. Multivariate twin modeling methods using continuous and categorized variables were performed, also controlling for age and gender.

RESULTS

Our findings suggested that forbidden thoughts and washing demonstrated the strongest genetic overlap with other AD symptoms, while ordering was genetically related to OCRD symptoms. Common genetic influences on checking symptoms were best estimated when modeling OCRDs together with AD symptoms. Common environmental factors of ordering and checking were shared with AD symptoms.

CONCLUSIONS

Important shared genetic and environmental risk factors exist between OCD, OCRDs, and ADs, but which vary alongside the expression of its major dimensions.

Exon-focused genome-wide association study of obsessive-compulsive disorder and shared polygenic risk with schizophrenia

Common single-nucleotide polymorphisms (SNPs) account for a large proportion of the heritability of obsessive-compulsive disorder (OCD). Co-ocurrence of OCD and schizophrenia is commoner than expected based on their respective prevalences, complicating the clinical management of patients. This study addresses two main objectives: to identify particular genes associated with OCD by SNP-based and gene-based tests; and to test the existence of a polygenic risk shared with schizophrenia. The primary analysis was an exon-focused genome-wide association study of 370 OCD cases and 443 controls from Spain. A polygenic risk model based on the Psychiatric Genetics Consortium schizophrenia data set (PGC-SCZ2) was tested in our OCD data. A polygenic risk model based on our OCD data was tested on previous data of schizophrenia from our group. The most significant association at the gene-based test was found at DNM3 (P=7.9 × 10(-5)), a gene involved in synaptic vesicle endocytosis. The polygenic risk model from PGC-SCZ2 data was strongly associated with disease status in our OCD sample, reaching its most significant value after removal of the major histocompatibility complex region (lowest P=2.3 × 10(-6), explaining 3.7% of the variance). The shared polygenic risk was confirmed in our schizophrenia data. In conclusion, DNM3 may be involved in risk to OCD. The shared polygenic risk between schizophrenia and OCD may be partially responsible for the frequent comorbidity of both disorders, explaining epidemiological data on cross-disorder risk. This common etiology may have clinical implications.

Mortality Among Persons With Obsessive-Compulsive Disorder in Denmark

IMPORTANCE

Several mental disorders have consistently been found to be associated with decreased life expectancy, but little is known about whether this is also the case for obsessive-compulsive disorder (OCD).

OBJECTIVE

To determine whether persons who receive a diagnosis of OCD are at increased risk of death.

DESIGN, SETTING, AND PARTICIPANTS

Using data from Danish registers, we conducted a nationwide prospective cohort study with 30 million person-years of follow-up. The data were collected from Danish longitudinal registers. A total of 3 million people born between 1955 and 2006 were followed up from January 1, 2002, through December 31, 2011. During this period, 27,236 people died. The data were analyzed primarily in June 2015.

MAIN OUTCOMES AND MEASURES

We estimated mortality rate ratios (MRRs), adjusted for calendar year, age, sex, maternal and paternal age, place of residence at birth, and somatic comorbidities, to compare persons with OCT with persons without OCD.

RESULTS

Of 10,155 persons with OCD (5935 women and 4220 men with a mean [SD] age of 29.1 [11.3] years who contributed a total of 54,937 person-years of observation), 110 (1.1%) died during the average follow-up of 9.7 years. The risk of death by natural or unnatural causes was significantly higher among persons with OCD (MRR, 1.68 [95% CI, 1.31-2.12] for natural causes; MRR, 2.61 [95% CI, 1.91-3.47] for unnatural causes) than among the general population. After the exclusion of persons with comorbid anxiety disorders, depression, or substance use disorders, OCD was still associated with increased mortality risk (MRR, 1.88 [95% CI, 1.27-2.67]).

CONCLUSIONS AND RELEVANCE

The presence of OCD was associated with a significantly increased mortality risk. Comorbid anxiety disorders, depression, or substance use disorders further increased the risk. However, after adjusting for these and somatic comorbidities, we found that the mortality risk remained significantly increased among persons with OCD.

Genetic Moderation of Stress Effects on Corticolimbic Circuitry

Stress exposure is associated with individual differences in corticolimbic structure and function that often mirror patterns observed in psychopathology. Gene x environment interaction research suggests that genetic variation moderates the impact of stress on risk for psychopathology. On the basis of these findings, imaging genetics, which attempts to link variability in DNA sequence and structure to neural phenotypes, has begun to incorporate measures of the environment. This research paradigm, known as imaging gene x environment interaction (iGxE), is beginning to contribute to our understanding of the neural mechanisms through which genetic variation and stress increase psychopathology risk. Although awaiting replication, evidence suggests that genetic variation within the canonical neuroendocrine stress hormone system, the hypothalamic-pituitary-adrenal axis, contributes to variability in stress-related corticolimbic structure and function, which, in turn, confers risk for psychopathology. For iGxE research to reach its full potential it will have to address many challenges, of which we discuss: (i) small effects, (ii) measuring the environment and neural phenotypes, (iii) the absence of detailed mechanisms, and (iv) incorporating development. By actively addressing these challenges, iGxE research is poised to help identify the neural mechanisms underlying genetic and environmental associations with psychopathology.

Symptoms of generalized anxiety disorder but not panic disorder at age 15 years increase the risk of depression at 18 years in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort study

BACKGROUND

Generalized anxiety disorder (GAD) and panic disorder (PD) differ in their biology and co-morbidities. We hypothesized that GAD but not PD symptoms at the age of 15 years are associated with depression diagnosis at 18 years.

METHOD

Using longitudinal data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort we examined relationships of GAD and PD symptoms (measured by the Development and Well-Being Assessment) at 15 years with depression at 18 years (by the Clinical Interview Schedule - Revised) using logistic regression. We excluded adolescents already depressed at 15 years and adjusted for social class, maternal education, birth order, gender, alcohol intake and smoking. We repeated these analyses following multiple imputation for missing data.

RESULTS

In the sample with complete data (n = 2835), high and moderate GAD symptoms in adolescents not depressed at 15 years were associated with increased risk of depression at 18 years both in unadjusted analyses and adjusting for PD symptoms at 15 years and the above potential confounders. The adjusted odds ratio (OR) for depression at 18 years in adolescents with high relative to low GAD scores was 5.2 [95% confidence interval (CI) 3.0-9.1, overall p < 0.0001]. There were no associations between PD symptoms and depression at 18 years in any model (high relative to low PD scores, adjusted OR = 1.3, 95% CI 0.3-4.8, overall p = 0.737). Missing data imputation strengthened the relationship of GAD symptoms with depression (high relative to low GAD scores, OR = 6.2, 95% CI 3.9-9.9) but those for PD became weaker.

CONCLUSIONS

Symptoms of GAD but not PD at 15 years are associated with depression at 18 years. Clinicians should be aware that adolescents with GAD symptoms may develop depression.

Extreme Weather-driven Disasters and Children’s Health

Extreme weather events such as heat waves, extreme precipitation, and storm surges are likely to become more frequent and intense with climate change. Extreme weather-driven disasters (EWDDs) cause a substantial burden of childhood mortality and morbidity worldwide. We reviewed the published literature on EWDDs and their health impacts on children, and developed a conceptual model based on complex systems thinking to identify the health risks, vulnerabilities, and capacities of children in the context of EWDDs as a means of informing areas for adaptive intervention. We found that direct and indirect physical and mental impacts of EWDDs on child health are abundant and interrelate in complex ways. The literature review and modeling demonstrated the centrality of resilience at the level of the child and his or her direct environment, suggesting that mental health status may play a key role in a child’s experience of numerous other health outcomes of EWDDs. EWDDs interact with environmental and social systems and with individual children and their contexts in complex ways, the impacts of which are nonlinear and difficult to predict. Traditional perspectives on climate change-driven health impacts often overlook complex bio-psychosocial interactions, suggesting a need to work on preventive strategies to reduce vulnerability and build individual child resilience.

Stress-related regulation of the kynurenine pathway: Relevance to neuropsychiatric and degenerative disorders

The kynurenine pathway (KP), which is activated in times of stress and infection has been implicated in the pathophysiology of neurodegenerative and psychiatric disorders. Activation of this tryptophan metabolising pathway results in the production of neuroactive metabolites which have the potential to interfere with normal neuronal functioning which may contribute to altered neuronal transmission and the emergence of symptoms of these brain disorders. This review investigates the involvement of the KP in a range of neurological disorders, examining recent in vitro, in vivo and clinical discoveries highlights evidence to indicate that the KP is a potential therapeutic target in both neurodegenerative and stress-related neuropsychiatric disorders. Furthermore, this review identifies gaps in our knowledge with regard to this field which are yet to be examined to lead to a more comprehensive understanding of the role of KP activation in brain health and disease. This article is part of the Special Issue entitled 'The Kynurenine Pathway in Health and Disease'.

Dietary magnesium deficiency affects gut microbiota and anxiety-like behaviour in C57BL/6N mice

OBJECTIVE

Magnesium deficiency has been associated with anxiety in humans, and rodent studies have demonstrated the gut microbiota to impact behaviour.

METHODS

We investigated the impact of 6 weeks of dietary magnesium deficiency on gut microbiota composition and anxiety-like behaviour and whether there was a link between the two. A total of 20 C57BL/6 mice, fed either a standard diet or a magnesium-deficient diet for 6 weeks, were tested using the light-dark box anxiety test. Gut microbiota composition was analysed by denaturation gradient gel electrophoresis.

RESULTS

We demonstrated that the gut microbiota composition correlated significantly with the behaviour of dietary unchallenged mice. A magnesium-deficient diet altered the gut microbiota, and was associated with altered anxiety-like behaviour, measured by decreased latency to enter the light box.

CONCLUSION

Magnesium deficiency altered behavior. The duration of magnesium deficiency is suggested to influence behaviour in the evaluated test.

Predictive value of familiality, stressful life events and gender on the course of obsessive-compulsive disorder

BACKGROUND

Familiality, stressful life events (SLE) and gender significantly affect the onset of obsessive-compulsive disorder (OCD). However, their combined impact on the probability of OCD chronicity is largely unknown. With the objective of clarifying their predictive value, we tested a model of interaction effects between these influences.

METHODS

A sample of 449 patients with OCD was systematically assessed for familial loading, exposure to stressful life events, gender and course of the disease at the OCD referral unit at Bellvitge University Hospital. Multiple ordinal logistic regression was used to test interaction models.

RESULTS

Familiality presented a main negative association with chronicity (OR=0.83, CI97.5%=0.70-0.98). This association was additively moderated by both exposure to SLE before onset and gender, and showed a positive slope among female patients not exposed to SLE before onset (Familiality*SLEbo: OR=0.69, CI97.5%=0.47-1; Familiality*gender: OR=1.30, CI97.5%=0.91-1.84).

LIMITATIONS

The findings are based on cross-sectional data. Assessment of course is based on a retrospective measure, which may imply the possibility of overestimation of chronicity.

CONCLUSIONS

The predictive value of familiality on the course of OCD is only partially informative as both SLEbo and gender modify the association. When other risk factors are included in the model, familiality may predict decreased chances of chronicity. The mediation effects identified could explain the discrepancies found in previous research on this topic. Increased chances of presenting a chronic course of OCD may be found in association with familial vulnerability among female patients not exposed to SLEbo.

Neuroinflammatory pathways in anxiety, posttraumatic stress, and obsessive compulsive disorders

As prevalence of anxiety, posttraumatic stress, and obsessive compulsive disorders continue to rise worldwide, increasing focus has been placed on immune mediated theories in understanding the underlying mechanisms of these disorders. Associations between the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and these disorders have been recognized in the scientific literature, specifically in regard to cortisol levels, as well as changes in pro- and anti-inflammatory cytokines. The present commentary will systematically assess the scientific literature within the past decade in regard to the psychoneuroimmunology of anxiety, posttraumatic stress, and obsessive compulsive disorders. Understanding the mechanisms of these disorders is essential in order to determine efficacious and targeted treatment strategies, which may lead to substantial improvements in overall functioning, as well as significant decreases in societal and economic burden.