Source: Rosemarie M. Bowler, Erica S. Kornblith, Jiehui Li, Shane W. Adams, Vihra V. Gocheva, Ralf Schwarzer and James E. Cone, American Journal of Industrial Medicine, Early View, April 20, 2016
From the abstract:
Background: After the 9/11/2001 World Trade Center (WTC) attack, many police-responders developed PTSD and might be vulnerable to develop depression and/or anxiety. Comorbidity of PTSD, depression, and/or anxiety is examined.
Method: Police enrollees from the WTC Health Registry were categorized into four groups based on comorbidity of PTSD, depression, and anxiety. DSM-IV diagnostic criteria for PTSD were used. Depression and anxiety were assessed with standardized psychometric inventories. Multinomial logistic regression was used to identify putative risk factors associated with comorbidity of PTSD.
Results: Of 243 (12.9% of total) police with probable PTSD, 21.8% had probable PTSD without comorbidity, 24.7% had depression, 5.8% had anxiety, and 47.7% had comorbid depression and anxiety. Risk factors for comorbid PTSD, depression, and anxiety include being Hispanic, decrease in income, experiencing physical injury on 9/11, experiencing stressful/traumatic events since 9/11, and being unemployed/retired.