These organizations have gathered particularly helpful information on people's responses to traumatic events, including the range of responses and descriptions of treatment options.

• American Psychological Association
• Grief and Renewal
• National Center on Post Traumatic Stress Disorder: Dealing with the Aftermath of Terrorism
• National Center on Post Traumatic Stress Disorder: Facts about PTSD
• National Center for Victims of Crime
• National Institute of Mental Health
• National Mental Health Association
• New York University Child Study Center

These organizations provide a range of services to people directly impacted by the 9/11 attacks.