A video is provided at the source, I recommend visitng ABC and watching their report.
source: ABC Dec 31, 2011
In a statistical model, PTSD mediated the association between exposure at the site and respiratory symptoms among both police officers and other types of responders, Evelyn Bromet of Stony Brook University in New York and colleagues reported online in the journal Psychological Medicine.
The results suggest “an indirect association of exposure with respiratory symptoms through PTSD, a finding that mirrors research conducted with Vietnam veterans,” the researchers wrote.
“Mental and physical health are integrally linked,” Bromet said in a statement. “It is not always obvious which one is the driver, but, in the end, what matters is that both mental and physical health are recognized and treated with equal care and respect.”
Respiratory illness and PTSD are both signature health problems among rescue workers who responded to the World Trade Center on Sept. 11, 2001, but the relationship between the two conditions isn’t clear.
So Bromet and her colleagues assessed 8,508 police officers and 12,333 other types of responders who were evaluated at the World Trade Center Medical Monitoring and Treatment Program between July 16, 2002, and Sept. 11, 2008.
The study was limited because the sample was comprised of volunteers, which could introduce bias, and by the fact that police officers may under-report PTSD symptoms because of concern about keeping their jobs.
video and more at the original source