The survey of 2,000 firefighters found that 62 percent of those who worked at the site of the World Trade Center collapse in the month following the attacks still experience at least occasional depression, said Samuel Bacharach, president of the Smithers Institute at Cornell University's School of Industrial and Labor Relations, which conducted the study.
Depression was half as frequent among firefighters who had not worked at ground zero, Bacharach said Monday.
The study also found elevated levels of stress and anxiety among those who worked at ground zero in the first month.
``These guys are under strain,'' Bacharach said. ``Depression is up, anxiety figures are up. All the basic indicators are really up.''
Findings of the survey, completed by firefighters last summer and fall, were to be released by the Smithers Institute on Tuesday.
The presidents of the firefighters and fire officers' unions declined to comment, saying they had not read the report.
FDNY officials will study the findings and work with the unions to implement any necessary changes in counseling, substance abuse treatment and other programs, spokesman Frank Gribbon said.
