title: Longitudinal study of probable post-traumatic stress disorder in firefighters exposed to the World Trade Center disaster.
abstract: BACKGROUND
  Symptoms of post-traumatic stress disorder (PTSD) have been reported even years after the terrorist attacks of September 11, 2001 (9/11).
  
  
  METHODS
  We used screening tools to assess the prevalence of probable PTSD in 9/11-exposed firefighters at two time points, within 6 months of 9/11 (baseline) and 3-4 years post-disaster (follow-up).
  
  
  RESULTS
  Five thousand six hundred fifty-six individuals completed assessments at both times. 15.5% reported probable PTSD post-9/11, 8.6% at baseline and 11.1% at follow-up, on average 2.9 (SD 0.5) years later. Analyses revealed that nearly half of all probable PTSD occurred as delayed onset (absent baseline, present follow-up). Compared with the resilient group (no probable PTSD at either time), probable PTSD at baseline, and delayed onset at follow-up were each associated with concomitant functional impairment (OR 19.5 and 18.9), respectively.
  
  
  CONCLUSIONS
  Similar percentages of firefighters met criteria for baseline and delayed onset probable PTSD at follow-up, years later. Both were associated with substantial functional impairment. Early risk identification could provide opportunities for mental health interventions before symptoms compromise work and social relationships.
authors.affiliation: Montefiore Medical Center, Department of Medicine, Bronx, New York, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Berninger
authors.forename: Mayris P
authors.initials: MP
authors.lastname: Webber
authors.forename: Justin K
authors.initials: JK
authors.lastname: Niles
authors.forename: Jackson
authors.initials: J
authors.lastname: Gustave
authors.forename: Roy
authors.initials: R
authors.lastname: Lee
authors.forename: Hillel W
authors.initials: HW
authors.lastname: Cohen
authors.forename: Kerry
authors.initials: K
authors.lastname: Kelly
authors.forename: Malachy
authors.initials: M
authors.lastname: Corrigan
authors.forename: David J
authors.initials: DJ
authors.lastname: Prezant
mesh_terms: D000328:Adult; D000437:Alcoholism; D016001:Confidence Intervals; D018450:Disease Progression; D005260:Female; D005390:Fires / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D015999:Multivariate Analysis; D009519:New York City / Q000453:epidemiology; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D015995:Prevalence; D011594:Psychometrics; D018570:Risk Assessment; D012307:Risk Factors; D047851:September 11 Terrorist Attacks / Q000706:statistics & numerical data*; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult