In the aftermath of the attacks on the World Trade Centre on 11 September 2001, many individuals working at the Ground Zero site during the clean-up operation had psychiatric symptoms (Reference LagnadoLagnado, 2001). Among these individuals is the group of ironworkers, who were exposed to extreme and extended distressing experiences because of their ‘front-line’ work (Reference KilgannonKilgannon, 2002) and were therefore at risk for post-trauma psychiatric morbidity (Reference MarshallMarshall, 2002). This study establishes the prevalence of, and risk factors for, psychiatric symptoms in this group.
Method
Ironworkers were recruited into the study from their work union, based on their perceived need or desire to attend the World Trade Centre Mental Health Screening Program at Mount Sinai Medical Center in New York City. In all, 124 ironworkers attended the medical centre in the period between 14 and 17 months after 9/11. They completed a written self-reporting structured screening questionnaire which they had not seen before, that had been devised for use in the screening programme. The questionnaire contained the following individual screening instruments: the Post-Traumatic Stress Disorder Checklist (PCL; Reference Blanchard and Jones-AlexanderBlanchard et al, 1996; Reference Cook, Elhai and AreanCook et al, 2005); the CAGE questionnaire (Reference EwingEwing, 1984) for symptoms of alcohol misuse; and the Patient Health Questionnaire (PHQ; Reference Spitzer, Kroenke and WilliamsSpitzer et al, 1999) which was divided into three sub-sections to screen for symptoms of panic attack (PHQ–1), generalised anxiety disorder (PHQ–2) and depression (PHQ–3). Screening positive for psychiatric symptoms was defined as screening positive in one or more of the individual screening instruments of the questionnaire. Those who did not screen positive in any of the instruments were considered having screened negative in the screening questionnaire. They were used as a comparison group for statistical analysis to assess for relative risk factors for psychiatric symptoms.
Apart from the individual screening instruments, the screening questionnaire also asked about the participant's gender, age, marital status, alcohol use since 9/11, injury to and/or death of family members, friends or co-workers on 9/11 and about 14 predetermined negative life events in the 12 months after 9/11. The events the participants could choose from were: the loss of job or income, house move, divorce from spouse, end of relationship with partner or best friend, domestic violence, mechanical car trouble, personal theft, a victim of mugging/violent attack, debt, serious illness and/or injury, criminal record, family illness, family death and serious family illness or death in the 6 months after 9/11. Threshold scores were used for each of the individual screening instruments (Reference Mayfield, McLeod and HallMayfield et al, 1974; Reference EwingEwing, 1984; Reference Bush, Shaw and ClearyBush et al, 1987; Reference Goldberg and WilliamsGoldberg & Williams, 1988; Liscow et al, 1995; Reference Spitzer, Kroenke and WilliamsSpitzer et al, 1999): 43 out of 85 established scores for the PCL, 1 out of 4 for the CAGE questionnaire, 8 out of 15 for the PHQ–1, 4 out of 7 in the PHQ–2 and 5 out of 9 on the PHQ–3.
We used an internet-based statistical analysis package (Reference CantrellCantrell, 2003) for Fisher's exact test to establish statistical significance when risk factors for psychiatric symptoms were compared between the participants and the comparison group. To calculate P-values more accurately, we used Yates’ continuity correction and two-tailed P-values.
Results
The screening questionnaire was completed by 124 ironworkers; no questionnaires were spoiled. More than half of ironworkers (n=73, 58.9%) screened positive for psychiatric symptoms and those who screened negative became the comparison group (n=51, 41.1%).
Demographic characteristics
All but one ironworker who attended the medical centre were male (n=123, 99.2%). Their mean age was 38 years (range 20–62, median 43) and the majority (n=87, 70.2%) were in a relationship at the time of attendance.
PCL and PHQ
Less than a fifth of the participants (n=23, 18.5%) screened positive on the PCL: 3.2% (n=4) screened positive for panic attack symptoms (PHQ–1), 6.5% (n=8) for generalised anxiety disorder symptoms (PHQ–2) and 5.7% (n=7) for depressive symptoms (PHQ–3).
CAGE questionnaire and alcohol use
About two-thirds of the participants (n=84, 67.7%) drank alcohol; 44% (n=37) have had a period since 9/11 when they have been drinking ‘more than usual’, 36.2% (n=17) while working at Ground Zero and 63.8% (n=30) after leaving their work at the site. Of the participants who drank alcohol, 39.3% (n=33) screened positive on the CAGE questionnaire.
Risk factors for psychiatric symptoms in individual screening instruments
Marital status
Relationship status was not a risk factor for screening positive on any individual screening instrument.
Alcohol use and misuse
A period of excessive alcohol use at any time since 9/11 was a significant risk factor for screening positive on the PCL (P=0.0082) and CAGE questionnaire (P=0.0001).
Injury to or death of a family member, friend or co-worker on 9/11
None of the participants suffered personal injury on 9/11. Injury to a family member, friend or co-worker on 9/11 was a risk factor for screening positive on the PCL (P=0.0318). Forty-seven participants (37.9%) lost a family member, friend or co-worker on 9/11, which was also a risk factor for screening positive on the PCL (P=0.0168) and CAGE questionnaire (P=0.0011).
Life events in the12 months after 9/11
Comparing those who had not experienced any of the 14 life events as stated in the questionnaire in the 12 months after 9/11 with those who had experienced one or more events, experiencing one or more life events was a risk factor for screening positive on the PCL (P=0.0125).
We also compared those who had experienced zero or one life event since 9/11 and those who had experienced two or more and found that the latter was a risk factor for screening positive on the PCL (P=0.0028) and PHQ–3(P=0.0065).
When comparing those who had experienced less than four life events since 9/11 and those who had experienced four or more, the latter was found to be a risk factor for screening positive on the PCL (P=0.0259), CAGE (P=0.0064) and PHQ–3(P=0.0513).
Discussion
Ironworkers who worked on the clean-up operation at Ground Zero in the aftermath of the World Trade Centre terrorist attacks have had psychiatric symptoms 14–17 months after 9/11. Symptoms of post-traumatic stress disorder were found in 18.5% of workers, 3.2% had panic attacks, 6.5% had symptoms of generalised anxiety disorder, 5.7% had symptoms of depression and 39.3% screened positive on the CAGE questionnaire suggesting harmful or dependent use of alcohol.
When compared with the 12-month prevalence rates of psychiatric symptoms in the general population of adult Americans, all but the depression rates are higher in the ironworkers. The rates in the general population are: 3.5% for post-traumatic stress disorder, 2.7% for panic disorder, 3.1% for generalised anxiety disorder, 6.7% for major depressive disorder, 3.1% for alcohol misuse and 1.3% for alcohol dependence (Reference Kessler, Chiu and DemlerKessler et al, 2005). This implicates that there is a causal relationship between psychiatric symptoms and the traumatic experience of working at Ground Zero during the clean-up operation, although the current study establishes only the prevalence of significant symptoms of these disorders, using the threshold scores of screening instruments, as opposed to the DSM–IV diagnosed prevalence of these disorders in the general population.
Excessive alcohol use since 9/11, injury to and/or death of a friend, family member or co-worker on 9/11 and at least one life event in the 6 months after 9/11 were statistically significant risk factors for psychiatric symptoms – those participants consistently screened positive in the individual screening instruments, primarily in the PCL and CAGE questionnaire. In the ironworker group, the prevalence of the death of a friend, family member or coworker on 9/11 was 37.9% compared with 20% in the general population. Participants of the World Trade Centre Mental Health Screening Program suggested that this was because many of their colleagues working in Manhattan and Brooklyn on 9/11 flocked to the Ground Zero site when the first of the two towers had collapsed to assist in rescuing survivors. However, they were killed when the second of the two towers collapsed. It is possible that this high prevalence of death or injury to friends, family members and co-workers has increased the risk of subsequent psychiatric illness in participants.
Comparing the results with other studies
Although some studies have found lower rates of post-traumatic stress disorder symptoms in exposed members of the general population after disasters (Reference Streimer, Cosstick and TennantStreimer et al, 1985; Reference Corneil, Beaton and MurphyCorneil et al, 1999; Reference Trout, Nimgade and MuellerTrout et al, 2002) others have found those rates to be greater (Reference Kessler, Sonnega and BrometKessler et al, 1995; Reference Wagner, Heinrichs and EhlertWagner et al, 1998; Reference North, Tivis and McMillenNorth et al, 2002a ; Reference Schlenger, Caddell and EbertSchlenger et al, 2002; Reference Silver, Holman and McIntoshSilver et al, 2002). This variation is likely caused by a number of variables, including the degree and duration of exposure, diagnostic stringency, the duration between locus event and the study, selection criteria, past psychiatric history, comorbidity and a number of other confounding variables.
Considerably more problems with alcohol misuse were identified in the current study than in the one comparable study of 181 firefighters involved in the clean-up operation after the Oklahoma City Bombing in 1995 (Reference North, Tivis and McMillenNorth et al, 2002a ). This may be attributed to the low threshold score for screening positive in the current study, but may also be caused by differences between ironworkers and the firefighters studied. Ironworkers taking part in the study anecdotally reported the industry as having a culture of socialisation involving excessive alcohol use outside work. They have also admitted to be generally disinclined to focus on or communicate their emotions, potentially placing them at increased risk of harmful alcohol use or developing alcohol dependence.
Risk factors in comparable studies
Some of the risk factors identified in the current study have also been observed in previous studies: ‘loss of a loved one’ and ‘unemployment’ after the traumatic event in Bryant & Harvey (Reference Bryant and Harvey1995); ‘significant loss’ and ‘injury’ in McFarlane (Reference McFarlane1988); ‘subsequent traumatic events’ in Carlier et al (Reference Carlier, Lamberts and Gersons1997) and Galea et al (Reference Galea, Vlahov and Resnick2002); ‘alcohol use and functional impairment’ in North et al (Reference North, Tivis and McMILLEN2002b ); and ‘chronic pain’ or ‘injury’ in Asmundson et al (Reference Asmundson, Norton and Allerdings1998).
Can the psychiatric symptoms be prevented?
Results of this study may help in planning preventive measures for future disaster scenarios. For example, observation and intervention could be focused on those ironworkers who use alcohol excessively, those whose family member, friend or co-worker was injured or killed in the disaster, or those who experience in the 12 months after the disaster one or more life events as specified in the screening questionnaire.
Limitations
Ironworkers who attended the World Trade Center Mental Health Screening Program were either selected by their union or volunteered. As this was based on perceived need or desire for mental healthcare, it caused a selection bias. The ironworkers’ alleged disinclination to focus on or communicate their emotions may have prevented some of them from attending the programme, thus missing those who potentially could have screened positive for psychiatric symptoms. The over-representation of White males in the group does not reflect the New York demographics and therefore the results cannot be generalised to the US population. However, these proportions do represent the predominance of males in the wider ironworker population.
The individual screening instruments used in the screening questionnaire, although useful for screening for psychiatric symptoms, do not provide a psychiatric diagnosis. Therefore, it has not been possible in our study to establish the prevalence of mental illness among ironworkers as a result of working at Ground Zero.
Using those who screened negative for psychiatric symptoms as the comparison group may have introduced a number of confounding factors not corrected for such as past or family psychiatric history.
The significant delay between 9/11 and attendance at the screening programme could introduce the confounding variable of psychiatric symptoms arising which are unrelated to the experience of working at Ground Zero. By the same token, the delay allowed to assess whether life events experienced in the 12 months since 9/11 were one of the causes of psychiatric illness.
Risk factors for psychiatric morbidity were established by showing a statistically significant correlation between two variables that are likely, but not proven, to be related. Statistical analyses with adjustments for confounding variables were not undertaken.
Declaration of interest
None.
Acknowledgements
Consent to publish data was kindly granted by the Institutional Review Board of the Mount Sinai School of Medicine, New York, USA. The screening programme was set up and run using a generous donation from the American National Institutes of Environmental Health Sciences of the National Institutes of Health.
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