[What are disasters and catastrophes?].

Psychiatric reactions to disasters have not received sufficient attention because it is widely accepted that human beings can endure any kind of extreme stress.A disaster is the consequence of an extraordinary event that destroys goods, kills people, produces physical or psychological harm but, above all, which overcomes the adaptive possibilities of the social group. Disasters have strong political background and consequences. They shake the life of a community and bear with them a set of questions about safety, social organization and meaning of life.Reactions to stress occur in stages, each one characterised by a specific psychological mechanism: pre-impact, alarm, impact, recoil, post-impact and reconciliation.Symptoms include flashbacks, difficulties in remembering, avoidance of stimuli, blunting of responses, high arousal level and obsessive ruminations.Biological, psycological and social factors participate in the pathogeny of these clinical pictures. Actas Esp Psiquiatr 2004;32(Supl. 2):1-16