Complex situations following war and natural disasters have a psychosocial impact not only on the individual, but also their family, community and the larger society. Fundamental changes in the functioning of the family and community can be observed as a result of these impacts. At the family level, the dynamics of single parent families, lack of trust amongmembers, changes in signi¢cant relationships and child rearing practices are seen. Communities tend to be more dependent, passive, silent, without leadership, mistrustful and suspicious. Additional adverse eiects include the breakdown of traditional structures, institutions and familiar ways of life, and deterioration in social norms, ethics and loss of social capital. Collective trauma canbe studied using sophisticated multilevel statistical analysis, with social capital as a marker. A variety of community level interventions have been tried, though a scienti¢cally robust evidence base for their eiectiveness has yet to be established.This article advocates that post disaster relief, rehabilitation and development programmes need to address the problem of collective trauma, particularly using integrated holistic approaches.