The snowball effect: friendship moderates escalations in depressed affect among avoidant and excluded children.

A three-wave longitudinal study conducted with preadolescent boys and girls (N = 231 at Time 1 [T1]) was used to assess the hypotheses that aspects of social withdrawal would be predictors of a "snowball" cascade of depressed affect, and that friendship experiences would moderate these effects. Consistent with these hypotheses, multilevel modeling showed that measures of avoidance and exclusion at T1 were associated with concurrent levels of depressed affect and were antecedent to escalating trajectories of depressed affect over time. These accelerating growth curves fit a snowball cascade model. The analyses also showed the protective effects of friendship. Specifically, the snowball effect was limited to avoidant and excluded children who were friendless. Depressed affect did not increase among avoidant and excluded children who were friended.