At a workshop held from October 30 to November 1, 2001, 58 disaster mental health experts from 6 countries met to discuss the impact of early psychological interventions and identify what does and does not work, as well as the knowledge gaps. For the purpose of the workshop and this report, an "early intervention" is defined as "any form of psychological intervention delivered within the first four weeks following an incident of mass violence or disasters." Once established, services may remain in place for the long-term. The workshop participants noted that there are few randomized controlled trials of psychological interventions following mass violence; however, existing randomized controlled trial data, often from studies of other types of traumatic events, suggest some guidance on best practice. The findings indicate that early, brief, and focused psychotherapeutic intervention can reduce distress in bereaved spouses, parents, and children. Selected cognitive behavioral approaches may help reduce the incidence, duration, and severity of acute stress disorder, posttraumatic stress disorder, and depression in survivors; however, early interventions in the form of single one-on-one recounting of events and expression of emotions evoked by a traumatic event do not consistently reduce risks of later posttraumatic stress disorder or related adjustment difficulties. Workshop participants concluded there is no evidence that eye movement desensitization and reprocessing as an early mental health intervention following mass violence and disasters is a treatment of choice over other approaches. Other issues discussed are key considerations for timing early interventions; screening for survivors; who should be selected for follow-up and over how long a period; expertise, skills, and training for providers of early intervention services; research and evaluation; ethical issues; and key questions that should be addressed within the field of early intervention. The workshop participants recommend that this report be reviewed by those officials who must decide what mental health services to include in the local, State, and national responses to survivors of mass violence and terrorism. Appended material on key components of early intervention, guidance for timing of early interventions, resource organizations, training of the early intervention workforce, additions and dissenting opinions, literature review tables, and 130 references