To assess the prevalence and correlates of post-traumatic stress disorder (PTSD), major depression and anxiety disorders other than PTSD, among three samples with different level of exposure to the March 11, 2004 terrorist attacks in Madrid.

We sampled three groups of persons—those injured in the attacks, the residents of Alcala de Henares, and police officers involved with the rescue effort—with different exposure to the March 11, 2004 terrorist attacks, using random sampling from comprehensive censuses of all three groups. In person interviews were conducted with all three groups between 5 and 12 weeks after March 11, 2004. Questionnaire included assessment of socio-demographic characteristics, of PTSD using the Davidson trauma scale, and of a range of psychiatric illnesses using the mini international neuropsychiatric interview (MINI).

The overall sample included 127 persons injured in the attack, 485 residents of Alcalá de Henares, and 153 policemen involved in rescue. Of all three groups 57.5%, 25.9% and 3.9% of persons, respectively, reported symptoms consistent with any assessed psychiatric disorder. The use of psychoactive medication before March 11, 2004 was consistently the main predictor of PTSD and major depression among those injured and of major depression and anxiety disorders others than PTSD among residents of Alcala.

There was a substantial burden of psychological consequences of the March 11, 2004 terrorist attacks two months after the event. Persons with prior mental illness are at higher risk of post-event psychopathology, across groups of exposure.