Joyce Weeland

ORCHIDS: an Observational Randomized Controlled Trial on Childhood Differential Susceptibility

BackgroundA central tenet in developmental psychopathology is that childhood rearing experiences have a major impact on children’s development. Recently, candidate genes have been identified that may cause children to be differentially susceptible to these experiences (i.e., susceptibility genes). However, our understanding of the differential impact of parenting is limited at best. Specifically, more experimental research is needed. The ORCHIDS study will investigate gene-(gene-)environment interactions to obtain more insight into a) moderating effects of polymorphisms on the link between parenting and child behavior, and b) behavioral mechanisms that underlie these gene-(gene-)environment interactions in an experimental design.Methods/DesignThe ORCHIDS study is a randomized controlled trial, in which the environment will be manipulated with an intervention (i.e., Incredible Years parent training). In a screening, families with children aged 4–8 who show mild to (sub)clinical behavior problems will be targeted through community records via two Dutch regional healthcare organizations. Assessments in both the intervention and control condition will be conducted at baseline (i.e., pretest), after 6 months (i.e., posttest), and after 10 months (i.e., follow-up).DiscussionThis study protocol describes the design of a randomized controlled trial that investigates gene-(gene-)environment interactions in the development of child behavior. Two hypotheses will be tested. First, we expect that children in the intervention condition who carry one or more susceptibility genes will show significantly lower levels of problem behavior and higher levels of prosocial behavior after their parent(s) received the Incredible Years training, compared to children without these genes, or children in the control group. Second, we expect that children carrying one or more susceptibility genes will show a heightened sensitivity to changes in parenting behaviors, and will manifest higher emotional synchronization in dyadic interchanges with their parents. This may lead to either more prosocial behavior or antisocial behavior depending on their parents’ behavior.Trial registrationDutch Trial Register (NTR3594)

Commentary Research on gene–environment interdependence: Honing the tools and examining the angles

The insightful overview by Sir Michael Rutter (this issue) on gene–environment interdependence comes about 10 years after the breakthrough Science publications on gene–environment interactions (G×E) involving the MAOA and 5-HTT genes by Caspi et al. (2002, 2003). Since then, a field of research has burgeoned that has produced replications as well as intriguing new evidence of gene–environment interdependence. At the same time, however, the field has witnessed a growing scepticism about the relevance of studying gene–environment interactions and has seen replication failures (see Duncan & Keller, 2011; Risch et al., 2009). Against this backdrop, we comment and elaborate on several of the key issues raised by Rutter, and suggest some directions for future research on G×E. Specifically, we discuss (1) replication issues; (2) the crucial role of experiments in understanding gene–environment interdependence; (3) current unknowns with regard to differential susceptibility; and (4) clinical and practical implications of G×E research.

5-HTTLPR Expression Outside the Skin: An Experimental Test of the Emotional Reactivity Hypothesis in Children

Background There is increasing evidence that variation in the promoter region of the serotonin transporter gene SLC6A4 (i.e., the 5-HTTLPR polymorphism) moderates the impact of environmental stressors on child psychopathology. Emotional reactivity −the intensity of an individual’s response to other’s emotions− has been put forward as a possible mechanism underlying these gene-by-environment interactions (i.e., G×E). Compared to children homozygous for the L-allele (LL-genotypes), children carrying an S-allele (SS/SL-genotypes), specifically when they have been frequently exposed to negative emotions in the family environment, might be more emotionally reactive and therefore more susceptible to affective environmental stressors. However, the association between 5-HTTLPR and emotional reactivity in children has not yet been empirically tested. Therefore, the goal of this study was to test this association in a large-scale experiment. Methods Children (N = 521, 52.5% boys, Mage = 9.72 years) were genotyped and randomly assigned to happy, angry or neutral dynamic facial expressions and vocalizations. Motor and affective emotional reactivity were assessed through children’s self-reported negative and positive affect (n = 460) and facial electromyography activity (i.e., fEMG: the zygomaticus or “smile” muscle and the corrugator or “frown” muscle, n = 403). Parents reported on their negative and positive parenting behaviors. Results Children mimicked and experienced the emotion they were exposed to. However, neither motor reactivity nor affective reactivity to these emotions depended on children’s 5-HTTLPR genotype: SS/SL-genotypes did not manifest any stronger response to emotional stimuli than LL-genotypes. This finding remained the same when taking the broader family environment into account, controlling for kinship, age, gender and genetic ancestry, and when including a tri-allelic factor. Conclusions We found no evidence for an association between the 5-HTTLPR polymorphism and children’s emotional reactivity. This finding is important, in discounting one potential underlying endophenotype of G×E between the 5-HTTLPR and affective environmental stressors.

Perception is key? : Does perceptual sensitivity and parenting behavior predict children's reactivity to others' emotions?

When interacting with other people, both childrens biological predispositions and past experiences play a role in how they will process and respond to social-emotional cues. Children may partly differ in their reactions to such cues because they differ in the threshold for perceiving such cues in general. Theoretically, perceptual sensitivity (i.e., the amount of detection of slight, low-intensity stimuli from the external environment independent of visual and auditory ability) might, therefore, provide us with specific information on individual differences in susceptibility to the environment. However, the temperament trait of perceptual sensitivity is highly understudied. In an experiment, we tested whether school-aged childrens (N=521, 52.5% boys, Mage=9.72years, SD=1.51) motor (facial electromyography) and affective (self-report) reactivities to dynamic facial expressions and vocalizations is predicted by their (parent-reported) perceptual sensitivity. Our results indicate that childrens perceptual sensitivity predicts their motor reactivity to both happy and angry expressions and vocalizations. In addition, perceptual sensitivity interacted with positive (but not negative) parenting behavior in predicting childrens motor reactivity to these emotions. Our findings suggest that perceptual sensitivity might indeed provide us with information on individual differences in reactivity to social-emotional cues, both alone and in interaction with parenting behavior. Because perceptual sensitivity focuses specifically on whether children perceive cues from their environment, and not on whether these cues cause arousal and/or whether children are able to regulate this arousal, it should be considered that perceptual sensitivity lies at the root of such individual differences.

Corrigendum to “Intervention Effectiveness of The Incredible Years: New Insights Into Sociodemographic and Intervention-Based Moderators” [Behavior Therapy 48 (2017) 1–18]

The authors regret that the effect sizes in the original manuscript are incorrect. The correct effect sizes, which are on average larger than reported in the original manuscript, are attached to this corrigendum (see corrected Table 4). The corrected effect sizes do not change the interpretation of our results in terms of the effectiveness of The Incredible Years program or the magnitude of the effects (i.e., whether they are small, medium or large). The authors would like to apologise for any inconvenience caused.