Parental rejection in early adolescence predicts a persistent ADHD symptom trajectory across adolescence

Genetic Risk, Neighborhood Characteristics, and Behavioral Difficulties Among African American Adolescents Living in Very Low-Income Neighborhoods

Behavioral difficulties among African American youth are disproportionately detrimental to their future well-being compared to when demonstrated by White American youth. The majority of gene-environment studies of behavior have been conducted with European ancestry samples, limiting our knowledge of these processes among African Americans. This study examined the influence of positive and negative neighborhood conditions, in the context of genetic risk, on behavioral difficulties among low-income African American adolescents. Data were from the Genes, Environment, and Neighborhood Initiative study of African American youth in high-poverty neighborhoods, n = 524, M age = 15.89, SD = 1.42. DNA samples were collected using the Oragene Discovery 500 series, and polygenic risk scores for behavioral difficulties computed. Neighborhood informal social control, social cohesion, physical disorder, and social disorder were assessed. Adolescent alcohol use, hyperactivity/inattention and conduct problems were examined as outcomes. After controlling for polygenic risk, lower levels of neighborhood social disorder and higher levels of social cohesion were associated with fewer youth-reported hyperactivity/inattention and conduct problems. Less social disorder also was associated with fewer parent-reported behavioral difficulties. Neighborhood characteristics did not moderate associations between genetic risk and the outcomes. Higher levels of positive and lower levels of negative neighborhood characteristics can be associated with lower levels of behavioral difficulties among African American youth living in poverty, even after taking into account genetic risk.

Internalizing and externalizing correlates of parental overprotection as measured by the EMBU: A systematic review and meta-analysis

Aspects of parenting including overprotection explain individual differences in child adjustment. This review and meta-analysis summarizes studies on parental overprotection and internalizing and externalizing problems. To ensure that findings could be compared as systematically as possible, the focus was on studies that used the overprotection scale of the Egna Minnen Beträffande Uppfostran ("Memories of my Parents' Upbringing") (EMBU) questionnaire, a popular instrument to measure parental overprotection. In total, we extracted 176 effects from 29 studies. A modified version of the Newcastle-Ottawa Scale was used to perform quality assessments for the included studies. Parental overprotection was associated positively with offspring internalizing and externalizing problems, with overall estimates ranging from r = .14 to .18. Moderator analyses suggested that effects of maternal were larger than effects of paternal overprotection. Other factors that moderated the strength of the association between overprotection and maladjustment included whether outcomes were self-reported or parent-reported, the design was cross-sectional or longitudinal, and publication year. Cultural context, age at exposure, and child sex did not explain differences between effect sizes. Most findings were based on cross-sectional studies and therefore do not constitute proof of causal relations. Many studies were of less-than-satisfactory quality regarding representativeness of the sample, descriptions of the data collection, and statistical analyses. There is a clear need for well-powered longitudinal studies to strengthen inferences about associations between parental overprotection and internalizing and externalizing problems.

The orphan receptor GPR88 controls impulsivity and is a risk factor for Attention-Deficit/Hyperactivity Disorder

The neural orphan G protein coupled receptor GPR88 is predominant in the striatum and cortex of both rodents and humans, and considered a potential target for brain disorders. Previous studies have shown multiple behavioral phenotypes in Gpr88 knockout mice, and human genetic studies have reported association with psychosis. Here we tested the possibility that GPR88 contributes to Attention Deficit Hyperactivity Disorder (ADHD). In the mouse, we tested Gpr88 knockout mice in three behavioral paradigms, best translatable between rodents and humans, and found higher motor impulsivity and reduced attention together with the reported hyperactivity. Atomoxetine, a typical ADHD drug, reduced impulsivity in mutant mice. Conditional Gpr88 knockout mice in either D1R-type or D2R-type medium spiny neurons revealed distinct implications of the two receptor populations in waiting and stopping impulsivity. Thus, animal data demonstrate that deficient GPR88 activity causally promotes ADHD-like behaviors, and identify circuit mechanisms underlying GPR88-regulated impulsivity. In humans, we performed a family-based genetic study including 567 nuclear families with DSM-IV diagnosis of ADHD. There was a minor association for SNP rs2036212 with diagnosis, treatment response and cognition. A stronger association was found for SNP rs2809817 upon patient stratification, suggesting that the T allele is a risk factor when prenatal stress is involved. Human data therefore identify GPR88 variants associated with the disease, and highlight a potential role of life trajectories to modulate GPR88 function. Overall, animal and human data concur to suggest that GPR88 signaling should be considered a key factor for diagnostic and treatment of ADHD.