Schooling and variation in the COMT gene: the devil is in the details

Role of Catechol-O-methyltransferase Val158Met Polymorphism on Transcranial Direct Current Stimulation in Swallowing

Transcranial direct current stimulation (tDCS) is one of the latest post-stroke dysphagia treatment modalities, and the effect of tDCS is known to be affected by various factors including genetic polymorphisms. However, the role of catechol-O-methyltransferase (COMT) polymorphisms on tDCS in swallowing is unclear. In this prospective pilot study, we aim to explore the effect of tDCS on the swallowing cortex and subsequent swallowing motor function according to COMT polymorphism. Twenty-four healthy participants received either anodal tDCS or sham mode tDCS on the mylohyoid motor cortex at random order, after inhibitory repetitive transcranial magnetic stimulation (rTMS) for preconditioning. The primary outcome was the changes of mylohyoid-motor-evoked potentials (MH-MEP) amplitude in each COMT polymorphism group, from the post-inhibitory rTMS baseline state to immediate, 30, and 60 min after tDCS. The secondary outcomes were the changes in swallowing function. The results showed that COMT Val/Val polymorphism showed improvement across time in the MH-MEP amplitudes and triggering time of swallowing after tDCS, whereas COMT Met carrier group did not show significant changes of MH-MEP or swallowing function across time. This therapeutic response variability of tDCS in the mylohyoid motor system according to COMT polymorphism support the importance of genetic analysis in individualized dysphagia treatment.

Spreading the Wealth: Developing Assessments of Cognitive Abilities in Non-WEIRD Countries

In this brief essay I reminisce on the ideas I encountered in Lev Vygotsky's lectures on pedology as an undergraduate student at Moscow State University in the USSR. Some of these ideas have been reliably stored in my professional memory and have influenced how my colleagues and I have approached the assessment of IQ (or general cognitive abilities) in countries other than the ones in which they were developed. Whereas the essay is autobiographical in nature, it attempts to make a generalizable point that spreading the wealth of existing knowledge, principles, and practice is as central to the progress of science as generating new knowledge.

Effectiveness of a social problem solving training in youth in detention or on probation: An RCT and pre-post community implementation

The effectiveness of a 10-session social problem-solving training (SPST) was evaluated in two independent studies in a juvenile justice (JJ) setting. In both studies, we aimed to examine main intervention effects on social problem-solving skills and recidivism, as well as differential effects as modulated by anger, anger regulation, and single nucleotide polymorphisms in the COMT gene. In Study 1, a randomized controlled trial (RCT), 289 male detainees (M_age= 14.95 years) were randomly assigned to SPST or treatment-as-usual (TAU). In Study 2, a pre-post community implementation, 187 youth (M_age = 16.03 years) on probation were assessed before and after SPST. No significant main effects of SPST on social problem solving or recidivism were shown in either study. With regard to differential effects, among youth in detention,COMT haplotypes predicted intervention effects on state anger. Moreover, independent of SPST, inward anger expression was associated with an increase in state anger from pre- to post and an increase in state anger with a decrease in social problem solving. Among youth on probation, COMT haplotypes predicted social problem-solving skills, and, in turn, an increase in social problem-solving skills decreased the odds of recidivism after SPST. The lack of main effects of SPST may be due to low program integrity in JJ settings. Juveniles' emotional and genetic characteristics might modulate the effectiveness of interventions in JJ settings. We recommend studying large samples to substantiate this observation.

Differences in Sensitivity to Environment Depending on Catechol-O-Methyltransferase (COMT) Gene? A Meta-analysis of Child and Adolescent Gene-by-Environment Studies

To date, several gene-by-environment (G×E) meta-analyses have been conducted to provide cumulative G×E evidence from previous inconsistent empirical studies; however, these meta-analyses have mainly focused on the serotonin transporter gene (5-HTTLPR). The present study aimed to conduct the first meta-analysis that tested whether and how an important dopaminergic gene-the catechol-O-methyltransferase (COMT) gene contributed to differences in child and adolescent environmental sensitivity. A total of 22 studies with 20,528 participants involving in various developmental outcomes (e.g., externalizing problems, emotional problems, cognitive development and social behaviors) met the inclusion criteria. The pooled effect size of environment-outcome associations in the Met-allele carriers (r = 0.11, 95% CI = [0.07, 0.15], p < .001) did not significantly differ from that in the Val/Val homozygotes (r = 0.14, 95% CI = [0.08, 0.20], p < 0.001) (Q_contrast (1) = 0.37, p = 0.54). The aggregated Liptak-Stouffer Z-score that combined the p-values of the COMT-environment interaction yield a nonsignificant result (p = 0.52). Moreover, outcome domain, sample age, ethnicity and assessment methods for the environment and the outcome did not moderate the effect sizes. Thus far, the COMT Val158Met polymorphism fails to explain the differences in sensitivity to environment. Future studies might incorporate more factors, such as polygenic effects of genetic pathways, epigenetics (EpiG) processing and sexual dimorphism, into the COMT-environment interaction equation.

Editorial: Illuminating the dark matter of developmental neuropsychiatric genetics - strategic focus for future research in child psychology and psychiatry

Research on genetic factors influencing cognitive and behavioural traits or which are central to the aetiology of neuropsychiatric diseases has been complicated by a furtive discrepancy between high heritability estimates and a scarcity of replicable gene-disorder associations. This 'missing heritability' has been either euphemised as the 'dark matter' of gene-trait association or aggravated as the 'looming crisis in behavioural genetics'. Nevertheless, in recognising the importance of this topic for our understanding of child psychiatric conditions and highlighting its commitment to the field, the Journal of Child Psychology and Psychiatry (JCPP) has for the first time appointed an editor with special responsibility for molecular (epi)genetics.