Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

A Friend in Need: The Role of Friendship Quality as a Protective Factor in Peer Victimization and Bullying

This study examined friendship quality as a possible moderator of risk factors in predicting peer victimization and bullying. Children (50 boys and 49 girls, ages 10 to 13 years) reported on the quality of their best friendship, as well as their bullying and victimization tendencies. Parents reported on their child’s internalizing and externalizing behaviors, in addition to bullying and victimization tendencies. Results indicated that externalizing problems were related to bullying behavior; however, friendship quality moderated this relation such that among children with externalizing behaviors, a high-quality friendship significantly attenuated bullying behavior. Internalizing problems and low friendship quality were significantly related to victimization; however, friendship quality did not moderate the relation between internalizing problems and victimization. Implications for interventions based on these findings are discussed

A Friend in Need: The Role of Friendship Quality as a Protective Factor in Peer Victimization and Bullying

This study examined friendship quality as a possible moderator of risk factors in predicting peer victimization and bullying. Children (50 boys and 49 girls, ages 10 to 13 years) reported on the quality of their best friendship, as well as their bullying and victimization tendencies. Parents reported on their child’s internalizing and externalizing behaviors, in addition to bullying and victimization tendencies. Results indicated that externalizing problems were related to bullying behavior; however, friendship quality moderated this relation such that among children with externalizing behaviors, a high-quality friendship significantly attenuated bullying behavior. Internalizing problems and low friendship quality were significantly related to victimization; however, friendship quality did not moderate the relation between internalizing problems and victimization. Implications for interventions based on these findings are discussed