The Web site for the Anxiety Disorders Association of America (ADAA) receives 
more than 5 million visits per month and thus represents a unique medium for the 
study of anxiety disorders. ADAA Web site users from October 2002 to January 
2003 were invited to complete a survey oriented toward trauma history and 
psychiatric sequelae. A diagnostic approximation of posttraumatic stress 
disorder (PTSD) was based on responses to the Trauma Questionnaire, the Davidson 
Trauma Scale, and questions about impairment. The Connor-Davidson Resilience 
Scale was also used. Variables were tested for their association with PTSD. 
Among 1558 participants, 87% had a history of trauma, and 38% had current PTSD. 
The population was comprised predominantly of white middle-class women, half of 
whom were married. More than 90% were first-time users of the site. Factors 
associated with PTSD included death of, or harm to, a loved one; personal 
history of incest, rape, or physical abuse; lower age; lower income; 
unemployment; missed work; increased medical care; dissatisfaction with 
psychotropic medication; depressive symptoms; and lower resilience. In this 
selective convenience sample, there were high rates of traumatization and PTSD. 
The demographics of this group are similar to those seen in previously studied 
populations that had contacted the ADAA. Furthermore, the factors associated 
with PTSD were like those in many community surveys. The ADAA Web site has the 
opportunity to benefit large numbers of highly distressed individuals.