The Anatomy of Friendship: Neuroanatomic Homophily of the Social Brain among Classroom Friends.

Homophily refers to the tendency to like similar others. Here, we ask if homophily extends to brain structure. Specifically: do children who like one another have more similar brain structures? We hypothesized that neuroanatomic similarity tied to friendship is most likely to pertain to brain regions that support social cognition. To test this hypothesis, we analyzed friendship network data from 1186 children in 49 classrooms. Within each classroom, we identified "friendship distance"-mutual friends, friends-of-friends, and more distantly connected or unconnected children. In total, 125 children (mean age = 7.57 years, 65 females) also had good quality neuroanatomic magnetic resonance imaging scans from which we extracted properties of the "social brain." We found that similarity of the social brain varied by friendship distance: mutual friends showed greater similarity in social brain networks compared with friends-of-friends (ß = 0.65, t = 2.03, P = 0.045) and even more remotely connected peers (ß = 0.77, t = 2.83, P = 0.006); friends-of-friends did not differ from more distantly connected peers (ß = -0.13, t = -0.53, P = 0.6). We report that mutual friends have similar "social brain" networks, adding a neuroanatomic dimension to the adage that "birds of a feather flock together."

Hopelessness and shame in relation to suicide attempts by Cuban adolescents.

Youth suicide rates in Cuba are very high compared with most other countries, despite considerable improvement in recent years. The purpose of our study was to determine whether hopelessness and shame distinguish adolescent suicide attempters from non-attempters, over and above the effects of depression and suicidal ideation. Participants were 844 Cuban adolescents from the province of Holguin in Eastern Cuba. The attempter groups included 38 participants being treated for suicide attempts in a day hospital and 82 participants in the community who self-reported a previous suicide attempt. The other participants were non-attempter controls. All participants were asked to complete measures of depression, hopelessness, shame and suicidal ideation. As expected, attempters scored higher than non-attempters on the control variables of depression and suicidal ideation. In addition, attempters self-reported greater shame, especially behavioral and characterological shame, than non-attempters. Contrary to our hypothesis, there was no significant difference in hopelessness between attempters and non-attempters. The results are inconsistent with the considerable narrative lore about hopelessness as a reason for suicide in Cuba and other socialist countries. However, some collective socialization practices may lead to shame.