Pubertal development moderates the importance of environmental influences on depressive symptoms in adolescent girls and boys

Associations Between Pubertal Stage and Depression: A Systematic Review of the Literature

The current article systematically reviews the literature and provides results from 36 studies testing the relation between pubertal stage and depression, as well as moderators and mediators of this relation. Results indicate that there is a significant relation between advancing pubertal stage and depression among girls, and this effect is strongest among White girls. Among boys, risk for depression does not increase with pubertal stage. Importantly, gonadal development appears to be driving the pubertal stage effect. Increasing hormone concentrations, shared environmental stressors, and body esteem appear to be mechanisms of this relation; increases in nonshared environmental stressors (negative life events, peer victimization) moderate the relation between pubertal stage and depression. Inconsistencies in findings across studies can be explained by methodological differences. Future work on this topic should control for age, examine differences by sex, and utilize within-person analyses to evaluate the effect of pubertal stage on depression over time.

Gender as a principle of the organization of clinical sleep research

In 2014 the National Institutes of Health required researchers to examine sex as a biological variable. While this approach is necessary to ensure adequate and appropriate female inclusion in research studies, it puts researchers at high risk for attributing their findings to biological sex differences when instead they may be more appropriately attributed to the influence and expectations of gender. In this paper, we specify how gender works as a principle of the social organization of symptoms, experiences, research, and clinical practice using obstructive sleep apnea symptomology to illustrate these patterns. We draw from psychologist Sandra Bem's account differentiating three specific mechanisms of gender: gender polarization, androcentrism, and biological essentialism.

Life Course Approaches to the Causes of Health Disparities

Reducing health disparities requires an understanding of the mechanisms that generate disparities. Life course approaches to health disparities leverage theories that explain how socially patterned physical, environmental, and socioeconomic exposures at different stages of human development shape health within and across generations and can therefore offer substantial insight into the etiology of health disparities. Life course approaches are informed by developmental and structural perspectives. Developmental perspectives emphasize how socially patterned exposures to risk factors during sensitive life stages shift health trajectories, whereas structural perspectives emphasize how social identity and position within socially patterned environments disproportionately allocate risk factors and resources, resulting in altered health trajectories. We conclude that the science of health disparities will be advanced by integrating life course approaches into etiologic and intervention research on health disparities. The following 4 strategies are offered to guide in this process: (1) advance the understanding of multiple exposures and their interactions, (2) integrate life course approaches into the understanding of biological mechanisms, (3) explore transgenerational transmission of health disparities, and (4) integrate life course approaches into health disparities interventions.

Adolescent depression linked to socioeconomic status? Molecular approaches for revealing premorbid risk factors

The means by which social environmental exposures influence risk of mental disorders is a persistent and still open question. A key candidate mechanism for the biologic mediation of environmental effects involves epigenetic factors, which regulate gene function without altering underlying DNA sequence. Recent work has shown that environmental exposures such as childhood abuse, family history of mental disorder, and low socioeconomic status (SES) associate with differential DNA methylation (5mC) - a relatively stable, but modifiable, epigenetic factor. However, the longitudinal relation among SES, 5mC, brain function, and risk of depression remains to be elucidated. Here, we briefly review literature relevant to these associations and discuss recent findings that, for the first time, prospectively demonstrate sequential links between low SES, changes in 5mC, changes in brain function, and risk of depression in a cohort of adolescents.

Pubertal timing in girls and depression: a systematic review

BACKGROUND

Because the incidence of depression increases after puberty, it is possible that pubertal timing in girls influences the onset of depression. Our objective was to assess the effect of early and late puberty in girls on the incidence of depression.

METHODS

We systematically searched relevant databases for controlled studies that assessed the impact of pubertal timing in girls on the incidence of depression or depressive symptoms. The last search was completed in August 2013. Two authors selected the studies, extracted the data, and assessed the quality of the evidence. Meta-analyses of the adjusted and unadjusted results were calculated using random effects.

RESULTS

Four cohort studies were included (n=8055 participants). Early puberty significantly increased the risk of new cases of depression in the unadjusted meta-analysis (RR=1.33; CI 95%: 1.02, 1.73) but not in the adjusted estimate of two of the included studies (RR=1.48; CI 95%: 0.69, 2.28). For late puberty, no significant associations were found (unadjusted RR=1.28; CI 95%: 0.87, 1.88). Two studies assessed the effect of early puberty on depressive symptoms and found positive associations. The quality of the available evidence was rated as very low.

LIMITATIONS

The polled results had wide confidence intervals, and the available evidence was of very low quality.

CONCLUSIONS

The available evidence supports little confidence regarding the impact of pubertal timing on the onset of depression in girls but suggests that early puberty in girls may increase the risk of depression. Further higher quality studies are needed to clarify the association between pubertal timing and the incidence of depression in girls and women.

Different trajectories of depressive symptoms in children and adolescents: predictors and differences in girls and boys

The development of depressive symptoms in childhood and adolescence can follow different pathways. This study examined heterogeneity in the development of self-reported depressive symptoms and the predictive influence of mothers' depressive symptoms, the number of life events, and loss events via growth mixture modeling over a four-year period in a large community sample of German children and adolescents (N = 3,902; mean age 11.39 years; 49.6% female). This procedure was conducted for the total sample as well as for separate samples of girls and boys. Four different classes of trajectories for the total and the girls' model were identified, but only three classes for the boys. Girls showed higher intercepts and stronger increases in symptoms over time, whereas boys displayed stronger decreases. In the total model, mothers' depressive symptoms and the number of life events significantly increased the level of depressive symptoms. In the gender models, only mothers' depressive symptoms showed significant influence on the level of symptoms in girls and boys, whereas for life events this was only true for boys. In every model, the significant predictors discriminated at least between some classes. Loss events showed no significant influence in any model. In sum, there are meaningful differences in the development of depressive symptoms in girls and boys. These results have several implications for prevention and future research.

Epigenetic Modulation of Mood Disorders

BACKGROUND

Mood disorders are expressed in many heterogeneous forms, varying from anxiety to severe major clinical depression. The disorders are expressed in individual variety through manifestations governed by co-morbidities, symptom frequency, severity, and duration, and the effects of genes on phenotypes. The underlying etiologies of mood disorders consist of complex interactive operations of genetic and environmental factors. The notion of endophenotypes, which encompasses the markers of several underlying liabilities to the disorders, may facilitate efforts to detect and define, through staging, the genetic risks inherent to the extreme complexity of disease state.

AIMS

This review evaluates the role of genetic biomarkers in assisting clinical diagnosis, identification of risk factors, and treatment of mood disorders.

METHODS

Through a systematic assessment of studies investigating the epigenetic basis for mood disorders, the present review examines the interaction of genes and environment underlying the pathophysiology of these disorders.

RESULTS

The majority of research findings suggest that the notion of endophenotypes, which encompasses the markers of several underlying liabilities to the disorders, may facilitate efforts to detect and define, through staging, the genetic risks inherent to the extreme complexity of the disease states. Several strategies under development and refinement show the propensity for derivation of essential elements in the etiopathogenesis of the disorders affecting drug-efficacy, drug metabolism, and drug adverse effects, e.g., with regard to selective serotonin reuptake inhibitors. These include: transporter gene expression and genes encoding receptor systems, hypothalamic-pituitary-adrenal axis factors, neurotrophic factors, and inflammatory factors affecting neuroimmune function. Nevertheless, procedural considerations of pharmacogenetics presume the parallel investment of policies and regulations to withstand eventual attempts at misuse, thereby ensuring patient integrity.

CONCLUSIONS

Identification of genetic biomarkers facilitates choice of treatment, prediction of response, and prognosis of outcome over a wide spectrum of symptoms associated with affective states, thereby optimizing clinical practice procedures. Epigenetic regulation of primary brain signaling, e.g., serotonin and hypothalamic-pituitary-adrenal function, and factors governing their metabolism are necessary considerations. The participation of neurotrophic factors remains indispensable for neurogenesis, survival, and functional maintenance of brain systems.