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Background:
Recent evidence from animal experiments and studies in humans suggests that early age at first drink (AFD) may lead to higher stress-induced drinking. The present study aimed to extend these findings by examining whether AFD interacted with stressful life events (SLE) and/or with daily hassles regarding the impact on drinking patterns among young adults.
Method:
In 306 participants of an epidemiological cohort study, AFD was assessed together with SLE during the past 3 years, daily hassles in the last month, and drinking behavior at age 22. As outcome variables, 2 variables were derived, reflecting different aspects of alcohol use: the amount of alcohol consumed in the last month and the drinking frequency, indicated by the number of drinking days in the last month.
Results:
Linear regression models revealed an interaction effect between the continuous measures of AFD and SLE on the amount of alcohol consumed. The earlier young adults had their first alcoholic drink and the higher the levels of SLE they were exposed to, the disproportionately more alcohol they consumed. Drinking frequency was not affected by an interaction of these variables, while daily hassles and their interaction with AFD were unrelated to drinking behavior.
Conclusions:
These findings highlight the importance of early age at drinking onset as a risk factor for later heavy drinking under high load of SLE. Prevention programs should aim to raise age at first contact with alcohol. Additionally, support in stressful life situations and the acquisition of effective coping strategies might prevent heavy drinking in those with earlier drinking onset.
Variation in the gene encoding for the norepinephrine transporter (NET, SLC6A2) has repeatedly been linked with ADHD, although there is some inconsistency regarding the association with specific genes. The variants for which most consistent association has been found are the NET variants rs3785157 and rs28386840. Here, we tested for their association with ADHD diagnosis and ADHD-related phenotypes during development in a longitudinal German community sample. Children were followed from age 4 to age 15, using diagnostic interviews to assess ADHD. Between the ages of 8 and 15 years, the Child Behavior Checklist (CBCL) was administered to the primary caregivers. The continuous performance task (CPT) was performed at age 15. Controlling for possible confounders, we found that homozygous carriers of the major A allele of the functional promoter variant rs28386840 displayed a higher rate of ADHD lifetime diagnosis. Moreover, homozygous carriers of the minor T allele of rs3785157 were more likely to develop ADHD and showed higher scores on the CBCL externalizing behavior scales. Additionally, we found that individuals heterozygous for rs3785157 made fewer omission errors in the CPT than homozygotes. This is the first longitudinal study to report associations between specific NET variants and ADHD-related phenotypes during the course of development. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
Background: Recently, first evidence has been reported for a geneparenting interaction (G x E) with regard to adolescent alcohol use. The present investigation set out to extend this research using the catechol-O-methyltransferase (COMT) Val158Met polymorphism as a genetic susceptibility factor. Moreover, the current study examined whether a potential G x E would be consistent with one of two models of geneenvironment interplay (genetic vulnerability vs. differential susceptibility). Methods: Data were collected as part of an ongoing epidemiological cohort study following the outcome of early risk factors from birth into adulthood. Two hundred and eighty-five participants (130 males, 155 females) were genotyped for the COMT Val(158) Met polymorphism and were administered an alcohol interview, providing measures of current frequency and amount of drinking at ages 15 and 19 years. Information on three dimensions of perceived parenting behavior was obtained from the 15-year-olds. Results: Adolescents homozygous for the Met allele showed higher drinking activity at age 19 years when their parents had engaged in less supervision or were less involved, while their drinking activity was reduced under conditions of favorable parenting. No such relationship was found in individuals carrying the Val allele. Conclusions: The present findings correspond with the pattern of results predicted by the differential susceptibility hypothesis, suggesting that environmental variation would have a greater impact in individuals carrying a genetic susceptibility such that, in this group, exposure to negative environmental conditions would result in more adverse outcomes and the experience of favorable conditions would lead to more positive outcomes.
Objective: A difficult or undercontrolled temperament, as well as harsh parental discipline or a lack of warmth, has long been regarded as risk factors for the development of externalizing problems. In addition, it has been suggested that children with difficult temperament are especially susceptible to rearing influences. We investigated the impact of early temperament and parenting and their interactions on externalizing behavior at school age.
Methods: Participants were 148 boys and 160 girls from a prospective longitudinal study on a high-risk sample. At ages 3 months and 2 years, temperament was assessed by a highly structured parent interview and standardized behavioral observations. Maternal parenting was assessed by videotaped behavioral observation and a parent questionnaire. Externalizing problems at age 8 years were measured by the Child Behavior Checklist.
Results: Using hierarchical linear regression analyses, we found that externalizing problems were predicted by psychosocial adversity and poor self-control, whereas no main effect for restrictive parenting or maternal empathy was found. Fearful-inhibited boys were positively affected by empathic and sensitive parenting, whereas girls who were low in self-control and/or fearful developed less externalizing problems with restrictive parenting.
Conclusion: Our results partly support the differential susceptibility hypothesis. In addition, they point toward gender-specific pathways in the development of externalizing problems.
Background: Dopamine plays an important role in orienting, response anticipation and movement evaluation. Thus, we examined the influence of functional variants related to dopamine inactivation in the dopamine transporter (DAT1) and catechol-O-methyltransferase genes (COMT) on the time-course of motor processing in a contingent negative variation (CNV) task.
Methods: 64-channel EEG recordings were obtained from 195 healthy adolescents of a community-based sample during a continuous performance task (A-X version). Early and late CNV as well as motor postimperative negative variation were assessed. Adolescents were genotyped for the COMT Val(158) Met and two DAT1 polymorphisms (variable number tandem repeats in the 3'-untranslated region and in intron 8).
Results: The results revealed a significant interaction between COMT and DAT1, indicating that COMT exerted stronger effects on lateralized motor post-processing (centro-parietal motor postimperative negative variation) in homozygous carriers of a DAT1 haplotype increasing DAT1 expression. Source analysis showed that the time interval 500-1000 ms after the motor response was specifically affected in contrast to preceding movement anticipation and programming stages, which were not altered.
Conclusions: Motor slow negative waves allow the genomic imaging of dopamine inactivation effects on cortical motor post-processing during response evaluation. This is the first report to point towards epistatic effects in the motor system during response evaluation, i.e. during the post-processing of an already executed movement rather than during movement programming.
Background: Recent animal and human studies indicate that the exposure to alcohol during early adolescence increases the risk for heavy alcohol use in response to stress. The purpose of this study was to examine whether this effect may be the consequence of a higher susceptibility to develop "drinking to cope" motives among early initiators. Methods: Data from 320 participants were collected as part of the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study. Structured interviews at age 15 and 19 were used to assess age at first alcohol experience and drunkenness. The young adults completed questionnaires to obtain information about the occurrence of stressful life events during the past 4 years and current drinking habits. In addition, alcohol use under conditions of negative states was assessed with the Inventory of Drinking Situations. Results: The probability of young adults' alcohol use in situations characterized by unpleasant emotions was significantly increased the earlier they had initiated the use of alcohol, even when controlling for current drinking habits and stressful life events. Similar results were obtained for the age at first drunkenness. Conclusions: The findings strengthen the hypothesis that alcohol experiences during early adolescence facilitate drinking to regulate negative affect as an adverse coping strategy which may represent the starting point of a vicious circle comprising drinking to relieve stress and increased stress as a consequence of drinking.
Early maternal care may counteract familial liability for psychopathology in the reward circuitry
(2018)
Reward processing is altered in various psychopathologies and has been shown to be susceptible to genetic and environmental influences. Here, we examined whether maternal care may buffer familial risk for psychiatric disorders in terms of reward processing. Functional magnetic resonance imaging during a monetary incentive delay task was acquired in participants of an epidemiological cohort study followed since birth (N = 172, 25 years). Early maternal stimulation was assessed during a standardized nursing/playing setting at the age of 3 months. Parental psychiatric disorders (familial risk) during childhood and the participants’ previous psychopathology were assessed by diagnostic interview. With high familial risk, higher maternal stimulation was related to increasing activation in the caudate head, the supplementary motor area, the cingulum and the middle frontal gyrus during reward anticipation, with the opposite pattern found in individuals with no familial risk. In contrast, higher maternal stimulation was associated with decreasing caudate head activity during reward delivery and reduced levels of attention deficit hyperactivity disorder (ADHD) in the high-risk group. Decreased caudate head activity during reward anticipation and increased activity during delivery were linked to ADHD. These findings provide evidence of a long-term association of early maternal stimulation on both adult neurobiological systems of reward underlying externalizing behavior and ADHD during development.
There is converging evidence suggesting a particular susceptibility to the addictive properties of nicotine among adolescents. The aim of the current study was to prospectively ascertain the relationship between age at first cigarette and initial smoking experiences, and to examine the combined effects of these characteristics of adolescent smoking behavior on adult smoking. It was hypothesized that the association between earlier age at first cigarette and later development of nicotine dependence may, at least in part, be attributable to differences in experiencing pleasurable early smoking sensations. Data were drawn from the participants of the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study from birth to adulthood. Structured interviews at age 15, 19 and 22 years were conducted to assess the age at first cigarette, early smoking experiences and current smoking behavior in 213 young adults. In addition, the participants completed the Fagerstrom Test for Nicotine Dependence. Adolescents who smoked their first cigarette at an earlier age reported more pleasurable sensations from the cigarette, and they were more likely to be regular smokers at age 22. The age at first cigarette also predicted the number of cigarettes smoked and dependence at age 22. Thus, both the age of first cigarette and the pleasure experienced from the cigarette independently predicted aspects of smoking at age 22.
IMPORTANCE: There is accumulating evidence relating maternal smoking during pregnancy to attention-deficit/hyperactivity disorder (ADHD) without elucidating specific mechanisms. Research investigating the neurobiological underpinnings of this disorder has implicated deficits during response inhibition. Attempts to uncover the effect of prenatal exposure to nicotine on inhibitory control may thus be of high clinical importance.
MAIN OUTCOMES AND MEASURES: Functional magnetic resonance imaging response, morphometric data, lifetime ADHD symptoms, and novelty seeking.
RESULTS: Participants prenatally exposed to nicotine exhibited a weaker response in the anterior cingulate cortex (t(168) = 4.46; peak Montreal Neurological Institute [MNI] coordinates x = -2, y = 20, z = 30; familywise error [FWE]-corrected P = .003), the right inferior frontal gyrus (t(168) = 3.65; peak MNI coordinates x = 44, y = 38, z = 12; FWE-corrected P = .04), the left inferior frontal gyrus (t(168) = 4.09; peak MNI coordinates x = -38, y = 36, z = 8; FWE-corrected P = .009), and the supramarginal gyrus (t(168) = 5.03; peak MNI coordinates x = 64, y = -28, z = 22; FWE-corrected P = .02) during the processing of the NoGo compared to neutral stimuli, while presenting a decreased volume in the right inferior frontal gyrus. These findings were obtained irrespective of the adjustment of confounders, ADHD symptoms, and novelty seeking. There was an inverse relationship between inferior frontal gyrus activity and ADHD symptoms and between anterior cingulate cortex activity and novelty seeking.
CONCLUSIONS AND RELEVANCE: These findings point to a functional involvement of prenatal exposure to tobacco smoke in neural alterations similar to ADHD, which underlines the importance of smoking prevention treatments.
Converging evidence emphasizes the role of an interaction between monoamine oxidase A (MAOA) genotype, environmental adversity, and sex in the pathophysiology of aggression. The present study aimed to clarify the impact of this interaction on neural activity in aggression-related brain systems. Functional magnetic resonance imaging was performed in 125 healthy adults from a high-risk community sample followed since birth. DNA was genotyped for the MAOA-VNTR (variable number of tandem repeats). Exposure to childhood life stress (CLS) between the ages of 4 and 11 years was assessed using a standardized parent interview, aggression by the Youth/Young Adult Self-Report between the ages of 15 and 25 years, and the VIRA-R (Vragenlijst Instrumentele En Reactieve Agressie) at the age of 15 years. Significant interactions were obtained between MAOA genotype, CLS, and sex relating to amygdala, hippocampus, and anterior cingulate cortex (ACC) response, respectively. Activity in the amygdala and hippocampus during emotional face-matching increased with the level of CLS in male MAOA-L, while decreasing in male MAOA-H, with the reverse pattern present in females. Findings in the opposite direction in the ACC during a flanker NoGo task suggested that increased emotional activity coincided with decreased inhibitory control. Moreover, increasing amygdala activity was associated with higher Y(A)SR aggression in male MAOA-L and female MAOA-H carriers. Likewise, a significant association between amygdala activity and reactive aggression was detected in female MAOA-H carriers. The results point to a moderating role of sex in the MAOAx CLS interaction for intermediate phenotypes of emotional and inhibitory processing, suggesting a possible mechanism in conferring susceptibility to violence-related disorders.
There is ample evidence that the early initiation of alcohol use is a risk factor for the development of later alcohol-related problems. The purpose of the current study was to examine whether this association can be explained by indicators of a common underlying susceptibility or whether age at drinking onset may be considered as an independent predictor of later drinking behavior, suggesting a potential causal relationship. Participants were drawn from a prospective cohort study of the long-term outcomes of early risk factors followed up from birth onwards. Structured interviews were administered to 304 participants to assess age at first drink and current drinking behavior. Data on risk factors, including early family adversity, parental alcohol use, childhood psychopathology and stressful life events, were repeatedly collected during childhood using standardized parent interviews. In addition, information on genotype was considered. Results confirmed previous work demonstrating that hazardous alcohol consumption is related to early-adolescent drinking onset. A younger age of first drink was significantly predicted by 5-HTTLPR genotype and the degree of preceding externalizing symptoms, and both factors were related to increased consumption or harmful alcohol use at age 19. However, even after controlling for these potential explanatory factors, earlier age at drinking onset remained a strong predictor of heavy alcohol consumption in young adulthood. The present longitudinal study adds to the current literature indicating that the early onset - adult hazardous drinking association cannot solely be attributed to shared genetic and psychopathologic risk factors as examined in this study.
Background:
Mother-infant interaction provides important training for the infant’s ability to cope with stress and the development of resilience. Prenatal stress (PS) and its impact on the offspring’s development have long been a focus of stress research, with studies highlighting both harmful and beneficial effects. The aim of the current study was to examine the possible influence of both psychological stress and hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy with mother-child dyadic behavior following stress exposure.
Methods:
The behavior of 164 mother-infant dyads during the still-face situation was filmed at six months postpartum and coded into three dyadic patterns: 1) both positive, 2) infant protesting-mother positive, and 3) infant protesting-mother negative. PS exposure was assessed prenatally according to psychological measures (i.e., psychopathological, perceived and psychosocial PS; n = 164) and HPA axis activity measures (maternal salivary cortisol, i.e., cortisol decline and area under the curve with respect to ground (AUCg); n = 134).
Results:
Mother-infant dyads in both the high- and low-stress groups showed decreasing positive and increasing negative dyadic behavior in the reunion episode, which is associated with the well-known “still-face” and “carry-over” effect. Furthermore, mother-infant dyads with higher psychosocial PS exhibited significantly more positive dyadic behavior than the low psychosocial PS group in the first play episode, but not in the reunion episode. Similarly, mother-infant dyads with high HPA axis activity (i.e. high AUCg) but steeper diurnal cortisol decline (i.e. cortisol decline) displayed significantly less negative behavior in the reunion episode than dyads with low HPA axis activity. No significant results were found for psychopathological stress and perceived stress.
Conclusions:
The results suggest a beneficial effect of higher psychosocial PS and higher prenatal maternal HPA axis activity in late gestation, which is in line with “stress inoculation” theories.
Background: Evidence from animal studies supports a role for serotonin transporter gene promoter polymorphism (5-HTTLPR) gene-environment interaction (G X E) in the development of excessive alcohol intake. Few studies in humans have been conducted on this topic, yielding inconsistent results. The present study aims to further explore G x E between 5-HTTLPR and exposure to psychosocial adversity on alcohol consumption in a high-risk community sample of young adults. Methods: Data were collected as part of the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study following the outcome of early risk factors from birth into young adulthood. At age 19 years, 309 participants (142 male participants, 167 female participants) were genotyped for the biallelic and triallelic 5-HTTLPR and were administered a 45-day alcohol timeline follow-back interview, providing measures of the total number of drinks and the number of binge drinking days. Psychosocial adversity was assessed at birth (family adversity) and at age 19 (negative life events). Results: In contrast to various previous reports, a significant G x E emerged, indicating that, when exposed to high psychosocial adversity, individuals with the LL genotype of 5-HTTLPR exhibited more hazardous drinking than those carrying the S allele or those without exposure to adversity. This effect, which was confined to male participants, held both for different classifications of 5-HTTLPR and different types of adversity. Conclusions: One explanation for the discrepant results might be heterogeneity in alcohol phenotypes. While the L allele relates more strongly to early-onset alcoholism, the S allele may be linked more closely to alcohol use associated with anxiety and depression.
Objective: To investigate the association of the neuropeptide Y (NPY) promoter polymorphism rs16147 with body mass index (BMI) during the course of development from infancy to adulthood.
Design: Longitudinal, prospective study of a German community sample.
Subjects: n = 306 young adults (139 males, 167 females).
Measurements: Participants' body weight and height were assessed at the ages of 3 months and 2, 4.5, 8, 11, 15 and 19 years. NPY rs16147 was genotyped.
Results: Controlling for a number of possible confounders, homozygote carriers of the rs16147 C allele exhibited significantly lower BMI scores when compared with individuals carrying the T allele. In addition, a significant genotype by age interaction emerged, indicating that the genotype effect increased during the course of development.
Conclusions: This is the first longitudinal study to report an association between rs16147 and BMI during childhood and adolescence. The finding that this effect increased during the course of development may either be due to age-dependent alterations in gene expression or to maturation processes within the weight regulation circuits of the central nervous system.
Findings on the etiology of aggressive behavior have provided evidence for an effect both of genetic factors, such as variation in the monoamine oxidase A (MAOA) gene, and adverse environmental factors. Recent studies have supported the existence of gene × environment interactions, with early experiences playing a key role. In the present study, the effects of prenatal nicotine exposure, MAOA genotype and their interaction on aggressive behavior during young adulthood were examined. In a sample of 272 young adults (129 males, 143 females) from an epidemiological cohort study, smoking during pregnancy was measured with a standardized parent interview at the offspring’s age of 3 months. Aggressive behavior was assessed between the ages of 19 and 25 years using the Young Adult Self-Report. DNA was genotyped for the MAOA 5′ untranslated region variable number of tandem repeats polymorphism (VNTR). Results revealed a significant interaction between MAOA and smoking during pregnancy, indicating higher levels of aggressive behavior in young adults carrying the MAOA low-expressing genotype who had experienced prenatal nicotine exposure (n = 8, p = .025). In contrast, in carriers of the MAOA high-expressing genotype, maternal smoking during pregnancy had no effect on aggressive behavior during young adulthood (n = 20, p = .145). This study extends earlier findings demonstrating an interaction between MAOA genotype and prenatal nicotine exposure on aggressive behavior into young adulthood. The results point to the long-term adverse effects of smoking during pregnancy on the offspring’s mental health, possibly underlining the importance of smoking cessation during pregnancy. According to the nature of the study (particularly sample size and power), analyses are exploratory and results need to be interpreted cautiously.