Genes, environments and depressions in young people

Association between increased serum interleukin-6 levels and sustained attention deficits in patients with major depressive disorder

BACKGROUND

The pathophysiology of cognitive impairment in patients with the major depressive disorder (MDD) may involve neuroinflammation mediated by cytokines.

OBJECTIVE

The aim of this study was to examine the serum interleukin-6 (IL-6) levels, sustained attention, and their association in patients with MDD.

METHODS

Thirty patients with MDD and 30 healthy controls were enrolled in this case-control study. Sustained attention was measured using the Rapid Visual Information Processing (RVP) task in the Cambridge Neuropsychological Tests Automated Battery. The serum IL-6 levels of all subjects were assessed by sandwich enzyme-linked immunosorbent assays.

RESULTS

There were significant differences in the log10RVP total hits, log10RVP total misses, and log10RVP mean latency between patients with MDD and healthy controls (F = 6.04, p = 0.017; F = 19.77, p < 0.0001; F = 14.42, p < 0.0001, respectively). The serum levels of Log10IL-6 were significantly higher in patients with MDD than in healthy controls (F = 192.27, p < 0.0001). The log10IL-6 levels were also positively correlated with the log10RVP mean latency in patients with MDD (r = 0.45, p = 0.013). A further stepwise multivariate regression analysis indicated that the log10IL-6 levels were significantly associated with the log10RVP mean latency in patients with MDD (β = 0.31, t = 2.41, p = 0.025).

CONCLUSIONS

Our data suggested that increased IL-6 levels were associated with the psychopathology of MDD, and that abnormal IL-6 levels were implicated in the impairment of sustained attention in patients with MDD.

Identification of IL6 as a susceptibility gene for major depressive disorder

Our previous work implied that interleukin 6 (IL6) may be a biological marker for major depressive disorder (MDD). In this study, we performed a comprehensive genetic study to determine the association between the gene encoding IL6 (IL6) and MDD in Han Chinese. There were 50 drug-naïve MDD patients and 50 healthy controls undergoing an mRNA expression study. A sample of 772 patients with MDD and 759 healthy controls were used for genetic analysis. Next, we performed an eQTL analysis to identify whether risk SNP(s) is associated with IL6 expression in brain. Our results showed that patients with MDD have higher levels of IL6 than healthy controls (P = 0.008). The SNP rs1800797 has a significant association with MDD (P = 0.01) in a dominant model. The eQTL analysis showed a marginally significant association between the rs1800797 and IL6 expression in the frontal cortex (P = 0.087). Our preliminary findings are suggestive of an association between rs1800797 and the risk of MDD. Further investigations are required to evaluate this association in larger samples to increase statistical power, and to examine the correlation between rs1800797 and IL6 methylation patterns.

Child Affected by Parental Relationship Distress

OBJECTIVE

A new condition, "child affected by parental relationship distress" (CAPRD), was introduced in the DSM-5. A relational problem, CAPRD is defined in the chapter of the DSM-5 under "Other Conditions That May Be a Focus of Clinical Attention." The purpose of this article is to explain the usefulness of this new terminology.

METHOD

A brief review of the literature establishing that children are affected by parental relationship distress is presented. To elaborate on the clinical presentations of CAPRD, four common scenarios are described in more detail: children may react to parental intimate partner distress; to parental intimate partner violence; to acrimonious divorce; and to unfair disparagement of one parent by another. Reactions of the child may include the onset or exacerbation of psychological symptoms, somatic complaints, an internal loyalty conflict, and, in the extreme, parental alienation, leading to loss of a parent-child relationship.

RESULTS

Since the definition of CAPRD in the DSM-5 consists of only one sentence, the authors propose an expanded explanation, clarifying that children may develop behavioral, cognitive, affective, and physical symptoms when they experience varying degrees of parental relationship distress, that is, intimate partner distress and intimate partner violence, which are defined with more specificity and reliability in the DSM-5.

CONCLUSION

CAPRD, like other relational problems, provides a way to define key relationship patterns that appear to lead to or exacerbate adverse mental health outcomes. It deserves the attention of clinicians who work with youth, as well as researchers assessing environmental inputs to common mental health problems.

Major Depressive Disorder Among Children and Adolescents

Depression among youths remains a public health concern, particularly because only a fraction of affected youths receive treatment. To obtain treatment, youths with depression must first be identified so that early intervention can occur. Furthermore, investigation of both more effective pharmacological agents and more widespread accessibility of cognitive-behavioral interventions are necessary. To address unmet needs in the identification and treatment of depression among youths, clinical counseling programs are being developed in primary care clinics and in schools to identify and treat depressive symptoms or milder major depressive disorder and have shown promising outcomes thus far in reducing depression and increasing quality of life.

Neurodevelopment and ages of onset in depressive disorders

How and why do clinical depressive disorders emerge in adolescence? In this Personal View, we present a neurodevelopmental theory to address causes for adolescent onsets of clinical depressive disorders. We argue that theories should account for three perplexing aspects of depressive disorders in adolescence: the episodic nature of depression; differences between sexes in rates of depression across development; and age-differentiated onsets. We consider how theories such as psychosocial acceleration, heterochronic brain development, dual-process models, glucocorticoid vulnerability hypothesis linked to early life stress, and epigenetic and genetic susceptibility might explain some aspects of adolescent depressive disorders. We argue that some synthesis between existing theories might be needed to establish a sufficient neurodevelopmental theoretical framework to explain onsets of depressive disorders in adolescence.