2015

Background. Ghrelin, a hunger hormone, has been implicated in the regulation of stress-response, anxiety and depression. Ghrelin-reactive immunoglobulins (Ig) were recently identified in healthy and obese humans showing abilities to increase ghrelin's stability and orexigenic effects. Here we studied if ghrelin-reactive Ig are associated with anxiety and depression and with the stress-induced cortisol response in a general population of adolescents. Furthermore, to test the possible infectious origin of ghrelin-reactive Ig, their levels were compared with serum IgG against common viruses. Methods. We measured ghrelin-reactive IgM, IgG and IgA in serum samples of 1199 adolescents from the Dutch TRAILS study and tested their associations with 1) anxiety and depression symptoms assessed with the Youth Self-Report, 2) stress-induced salivary cortisol levels and 3) IgG against human herpesvirus 1, 2, 4 and 6 and Influenza A and B viruses. Results. Ghrelin-reactive IgM and IgG correlated positively with levels of antibodies against Influenza A virus. Ghrelin-reactive IgM correlated negatively with antibodies against Influenza B virus. Ghrelin-reactive IgM correlated positively with anxiety scores in girls and ghrelin-reactive IgG correlated with stress-induced cortisol secretion, but these associations were weak and not significant after correction for multiple testing. Conclusion. These data indicate that production of ghrelin-reactive autoantibodies could be influenced by viral infections. Serum levels of ghrelin-reactive autoantibodies probably do not play a role in regulating anxiety, depression and the stress-response in adolescents from the general population.

Copyright © 2015 Elsevier Inc. All rights reserved.

The hypothalamic-pituitary-adrenal axis, autonomic nervous system, and immune system have been proposed to underlie the antidepressant effect of exercise. Using a population sample of 715 adolescents, we examined whether pathways from exercise to affective and somatic symptoms of depression were mediated by these putative mechanisms. Exercise (hours/week) and depressive symptoms were assessed at age 13.5 (± 0.5) and 16.1 (± 0.6). Cortisol and heart rate responses to a standardized social stress test and C-reactive protein levels were measured at age 16. Exercise was prospectively and inversely related to affective (B = -0.16, 95% CI = -0.30 to -0.03) but not somatic symptoms (B = -0.04, 95% CI = -0.21 to 0.13). Heart rate during social stress partially mediated this relationship (B = -0.03, 95% CI = -0.07 to -0.01). No other mediating effects were found. Hence, the autonomic stress system may play a role in the relationship between exercise and depressive symptoms.

© 2014 Society for Psychophysiological Research.

Background. In psychiatric genetics research, the volume of ambivalent findings on gene-environment interactions (G x E) is growing at an accelerating pace. In response to the surging suspicions of systematic distortion, we challenge the notion of chance capitalization as a possible contributor. Beyond qualifying multiple testing as a mere methodological issue that, if uncorrected, leads to chance capitalization, we advance towards illustrating the potential benefits of multiple tests in understanding equivocal evidence in genetics literature. Method. We focused on the interaction between the serotonin-transporter-linked promotor region (5-HTTLPR) and childhood adversities with regard to depression. After testing 2160 interactions with all relevant measures available within the Dutch population study of adolescents TRAILS, we calculated percentages of significant (p < .05) effects for several subsets of regressions. Using chance capitalization (i.e. overall significance rate of 5% alpha and randomly distributed findings) as a competing hypothesis, we expected more significant effects in the subsets of regressions involving: 1) interview-based instead of questionnaire-based measures; 2) abuse instead of milder childhood adversities; and 3) early instead of later adversities. Furthermore, we expected equal significance percentages across 4) male and female subsamples, and 5) various genotypic models of 5-HTTLPR. Results. We found differences in the percentages of significant interactions among the subsets of analyses, including those regarding sex-specific subsamples and genetic modeling, but often in unexpected directions. Overall, the percentage of significant interactions was 7.9% which is only slightly above the 5% that might be expected based on chance. Conclusion. Taken together, multiple testing provides a novel approach to better understand equivocal evidence on G x E, showing that methodological differences across studies are a likely reason for heterogeneity in findings - but chance capitalization is at least equally plausible.

The literature on relative age position effects is rather inconsistent. In this study we examined intra-classroom age position (or relative age) effects on Dutch adolescents' school progress and performance (as rated by teachers), physical development, temperamental development (fear and frustration), and depressive symptoms, all adjusted for age at the time of measurement. Data were derived from three waves of Tracking Adolescents' Individuals Lives Survey (TRAILS) of 2230 Dutch adolescents (baseline mean age 11.1, SD = 0.6, 51% girls). Albeit relative age predicted school progress (grade retention ORs = 0.83 for each month, skipped grade OR = 1.47, both p<.001), our key observation is the absence of substantial developmental differences as a result of relative age position in Dutch adolescents with a normative school trajectory, in contrast to most literature. For adolescents who had repeated a grade inverse relative age effects were observed, in terms of physical development and school performance, as well as on depressive symptoms, favoring the relatively young. Cross-cultural differences in relative age effect may be partly explained by the decision threshold for grade retention.

Background. The relationship between early adverse life events and later internalizing problems could be mediated by DNA methylation. Adversity has been associated with higher methylation levels in the glucocorticoid receptor gene (NR3C1) and the serotonin transporter gene (SLC6A4) in adolescents. We investigated cross-sectional and prospective associations of NR3C1 and SLC6A4 methylation with adolescents׳ clinical diagnoses of internalizing disorders and internalizing symptom scores. Methods. In a population sample (mean age=16.2) we measured DNA methylation in three regions of NR3C1 (NR3C1_1, N=454; NR3C1_2, N=904; NR3C1_3, N=412) and one region of SLC6A4 (N=939) at baseline. Internalizing problems were operationalized as clinical DSM-IV diagnoses, assessed at 3 year follow-up with a diagnostic interview, and internalizing symptom scores, assessed with Self-Report questionnaires at baseline and follow-up. Results. Only NR3C1_1 methylation was positively associated with risk of lifetime internalizing disorders, and with symptom scores at follow-up. However, after accounting for baseline symptom scores there was only a tendency for association with internalizing symptom scores at follow-up. There was no association between SLC6A4 methylation and risk of lifetime internalizing disorders. SLC6A4 methylation and internalizing symptom scores showed a tendency for association, also after accounting for baseline symptom scores. Limitations. There was no repeated measure of DNA methylation to study causality between methylation and internalizing problems. Gene expression data were not available. Conclusions. Although the role of gene methylation in the development of internalizing problems remains unclear, our findings suggest that gene methylation, particularly of NR3C1, may be involved in the development of internalizing problems in adolescence.

Copyright © 2015 Elsevier B.V. All rights reserved.

It is well-known that childhood adversities can have long-term effects on mental health, but a lot remains to be learned about the risk they bring about for a first onset of various psychiatric disorders, and how this risk develops over time. In the present study, which was based on a Dutch longitudinal population survey of adolescents TRAILS (N = 1,584), we investigated whether and how childhood adversities, as assessed with three different measures, affected the risk of developing an incident depressive, anxiety, or disruptive behavior in childhood and adolescence. In addition, we tested gender differences in any of the effects under study. The results indicated that depressive, anxiety and disruptive behavior disorders each had their own, characteristic, pattern of associations with childhood adversities across childhood and adolescence, which was maintained after adjustment for comorbid disorders. For depressive disorders, the overall pattern suggested a high excess risk of incidence during childhood, which decreased during adolescence. Anxiety disorders were characterized by a moderately increased incident risk during childhood, which remained approximately stable over time. Disruptive behavior disorders took an intermediate position. Of the three childhood adversities tested, an overall rating of the stressfulness of the childhood appeared to predict onset of psychiatric disorders best. To conclude, the risk of developing a psychiatric disorder after exposure to adversities early in life depends on the nature of the adversities, the nature of the outcome, and the time that has passed since the adversities without disorder onset.

Background. With psychopathology rising during adolescence and evidence suggesting that adult mental health burden is often due to disorders beginning in youth, it is important to investigate the epidemiology of adolescent mental disorders. Method. We analysed data gathered at ages 11 (baseline) and 19 years from the population-based Dutch TRacking Adolescents' Individual Lives Survey (TRAILS) study. At baseline we administered the Achenbach measures (Child Behavior Checklist, Youth Self-Report) and at age 19 years the World Health Organization's Composite International Diagnostic Interview version 3.0 (CIDI 3.0) to 1584 youths.
Results. Lifetime, 12-month and 30-day prevalences of any CIDI-DSM-IV disorder were 45, 31 and 15%, respectively. Half were severe. Anxiety disorders were the most common but the least severe whereas mood and behaviour disorders were less prevalent but more severe. Disorders persisted, mostly by recurrence in mood disorders and chronicity in anxiety disorders. Median onset age varied substantially across disorders. Having one disorder increased subjects' risk of developing another disorder. We found substantial homotypic and heterotypic continuity. Baseline problems predicted the development of diagnosable disorders in adolescence. Non-intact families and low maternal education predicted externalizing disorders. Most morbidity concentrated in 5-10% of the sample, experiencing 34-55% of all severe lifetime disorders.
Conclusions. At late adolescence, 22% of youths have experienced a severe episode and 23% only mild episodes. This psychopathology is rather persistent, mostly due to recurrence, showing both monotypic and heterotypic continuity, with family context affecting particularly externalizing disorders. High problem levels at age 11 years are modest precursors of incident adolescent disorders. The burden of mental illness concentrates in 5-10% of the adolescent population.

Background. Some adolescents function poorly in apparently benign environments, while others thrive despite hassles and difficulties. The aim of this study was to examine if adolescents with specialized skills in the recognition of either positive or negative emotions have a context-dependent risk of developing an anxiety or depressive disorder during adolescence, depending on exposure to positive or harsh parenting. Methods. Data came from a large prospective Dutch population study (N = 1539). At age 11, perceived parental rejection and emotional warmth were measured by questionnaire, and emotion recognition skills by means of a reaction-time task. Lifetime diagnoses of anxiety and depressive disorders were assessed at about age 19, using a standardized diagnostic interview. Results. Adolescents who were specialized in the recognition of positive emotions had a relatively high probability to develop an anxiety disorder when exposed to parental rejection (Bspecialization*rejection = 0.23, P < 0.01) and a relatively low probability in response to parental emotional warmth (Bspecialization*warmth = -0.24, P = 0.01), while the opposite pattern was found for specialists in negative emotions. The effect of parental emotional warmth on depression onset was likewise modified by emotion recognition specialization (B = -0.13, P = 0.03), but the effect of parental rejection was not (B = 0.02, P = 0.72). In general, the relative advantage of specialists in negative emotions was restricted to fairly uncommon negative conditions. Conclusions. Our results suggest that there is no unequivocal relation between parenting behaviors and the probability to develop an anxiety or depressive disorder in adolescence, and that emotion recognition specialization may be a promising way to distinguish between various types of context-dependent reaction patterns.

Objective. In adults, depression and inflammation are bidirectionally related. This association is less clear in adolescents. Moreover, somatic and cognitive depressive symptoms might be differentially related to inflammation. Lifestyle factors, as in adults, may play an important mediating role in adolescents. For the current study we evaluated trajectories of depressive symptoms in adolescence over a 5-year course and their relation with subsequent high-sensitivity C-reactive protein (hsCRP) levels, and examined lifestyle factors as mediators. Method. Participants of the TRacking Adolescents' Individual Lives' Survey (TRAILS; N = 1166) were followed from 2001 until 2008. Three biennial youth self-report (YSR) assessments of depressive symptoms were taken. Demographics, health, and lifestyle factors and levels of hsCRP were assessed at Wave 3. Latent-class analysis was used to determine trajectories of depression and general linear models to determine the association between depression trajectories and hsCRP. Finally, mediation analysis was performed to test mediation of lifestyle factors. Results. Persistently moderate to high depressive symptoms were associated with higher hsCRP levels. Results were unaltered when we adjusted for demographics and health variables. Smoking mediated the association between depressive symptoms total score and hsCRP, in large part. Persistently higher scores on somatic and cognitive symptom subscales were associated with higher levels of hsCRP than persistently low scores. These results were rendered nonsignificant after covariate adjustment. Conclusion. Persistent depressive symptoms were associated with subsequent higher levels of hsCRP, with somatic and cognitive symptoms contributing equally. The association was mediated by smoking behavior. These findings suggest that reducing adolescent depression and smoking are important starting points in the prevention of inflammatory diseases.

(c) 2015 APA, all rights reserved).

Background. Hypothalamic-pituitary-adrenal axis functioning, with cortisol as its major output hormone, has been presumed to play a key role in the development of psychopathology. Predicting affective disorders from diurnal cortisol levels has been inconclusive, whereas the predictive value of stress-induced cortisol concentrations has not been studied before. The aim of this study was to predict mental disorders over a 3-year follow-up from awakening and stress-induced cortisol concentrations. Method. Data were used from 561 TRAILS (TRacking Adolescents' Individual Lives Survey) participants, a prospective cohort study of Dutch adolescents. Saliva samples were collected at awakening and half an hour later and during a social stress test at age 16. Mental disorders were assessed 3 years later with the Composite International Diagnostic Interview (CIDI). Results. A lower cortisol awakening response (CAR) marginally significantly predicted new disorders [odds ratio (OR) 0.77, p = 0.06]. A flat recovery slope predicted disorders with a first onset after the experimental session (OR 1.27, p = 0.04). Recovery revealed smaller, non-significant ORs when predicting new onset affective or anxiety disorders, major depressive disorder, or dependence disorders in three separate models, corrected for all other new onsets. Conclusions. Our results suggest that delayed recovery and possibly reduced CAR are indicators of a more general risk status and may be part of a common pathway to psychopathology. Delayed recovery suggests that individuals at risk for mental disorders perceived the social stress test as less controllable and less predictable.