What do we now know about the mental health effects of the events of September 11, 2001? The best evidence contradicts early claims that these events had long-lasting negative effects or that watching the events on television inflicted a virtual trauma on the American people. Earlier claims were exaggerated and could have been shown to be inaccurate even at the time they were made. Available evidence now attests to the resiliency of the American people.
In my last blog post, I provided links to a pair of articles, one in JAMA: Journal of the American Medical Association, and the other in the Archives of General Psychiatry that claimed that Americans suffered substantial mental and physical health damage from learning of these events, and that these effects were exacerbated by watching them on television.
In this blog post, I will be suggesting that the two articles ignored available evidence. You might want use the links above to access these articles and confirm for yourself just what attention they gave to conflicting evidence, particularly the second paper that became available after more studies have been published.
Skeptical sleuthing found the claims made in these two articles to be backed only by weak evidence from an Internet survey of an atypical sample of Americans, almost none of whom were directly affected by the events of September 11, 2001. The assessment of psychological reactions 9/11 depended upon flawed measures, the validity of which was further compromised by changes the authors of these articles made in their wording and scoring.
Neither article confronted discrepancies between their claims and evidence available from other studies. The earlier JAMA article noted "several methodological differences between investigations make comparisons of rates of trauma-related symptoms across studies difficult." Okay, but we can take the quality of different studies into account in deciding what is the best evidence whether American suffered a collective, virtual trauma from the events of September 11, 2001.
American society was profoundly changed by those events, but what is being questioned is whether these changes substantially adversely affected the mental health of the American people. Of course, we can claim that in a loose, metaphorical sense the events of 9/11 were "traumatic", but that is a separate question from whether they registered a traumatic effect on the mental and physical health of the nation. Vague popular conceptions often do not fare well when translated into precise scientific hypotheses and are put to a test in studies with appropriate methodologies.
At the time of the publication of the JAMA article in 2002, a few studies were already coming available.
- One study used random digit dialing to contact 560 American adults 3 to 5 days after September 11. Respondents were asked 5 questions intended to assess stress responses and 44% endorsed at least one of them, with the greatest portion indicating that they felt upset when something reminded them of the recent events. When a follow-up study of the same sample became available, it noted that these effects had diminished by half two months later.
- Another study examined stress reactions 5 to 8 weeks after September 11 in 2001 among the residents of Manhattan and found that 7.5% had symptoms of PTSD and 10% had symptoms of depression. A follow-up article reported that television exposure was associated with PTSD symptoms only among persons directly affected by the attacks such as those with friends who were killed. A third study from the same sample found that the rates of probable PTSD fell to 0.6% six months later, a 92% drop!
- A third study used a web-based survey with 2273 adults and found "probable PTSD" was higher in New York City (11.2%) than in other areas of the country (2.7-4.0%). The survey also assessed overall psychological distress levels across the country and found it to be within expected ranges for a general community sample.
After the Silver and colleagues' 2002 JAMA article about trauma by television were published, a number of studies became available that were not acknowledged in their 2008 paper. These studies found
- No increase in the treatment of PTSD or other psychiatric disorders in veterans' clinics in either New York City nor the Washington DC area from six months before until six months after 9/11/2001.
- Use of psychotropic drugs in New York City increased from 12 weeks prior to 12 weeks after 9/11 only for who those who already had prescriptions, but otherwise no overall increase in prescriptions. There were no changes in prescriptions in Washington DC or nationwide.
Overall, the measures in other studies were generally better validated and more appropriate than Silver and colleagues' studies and the samples were either larger or allowed better comparisons in terms of peoples' degree of having been exposed to or affected by the events of 9/11. The only study that seems to offer the slightest agreement with Silver and her colleagues is the random digit dialing study that found 44% of the adult sampled reported a symptom of stress just after 9/11. However, critics have questioned whether these items could validly be assumed to assess stress and noted that the symptoms had almost entirely subsided by November 2001. In "When Being Upset Is Not A Mental Health Problem." English trauma expert and psychiatrist Simon Wessley commented "it is a general principle that professional should refrain from treating ailments that are going to get better fairly quickly anyway, since to do so waste resources, and exposes patients to the risk of side effects unnecessary treatment."
More evidence continues to accumulate and it further supports the substantial detrimental mental health effects on the American people of 9/11 are a myth.
However, a huge study by epidemiologist Naomi Breslau and her colleagues with over 34,000 respondents dwarfs the size of all previous studies combined, it used interviews more appropriate to assessing posttraumatic stress, and it was conducted face-to-face, which elicit more valid information that Internet based surveys. Results of the study seemed decisively to lay to rest any suggestion that the events of 9/11 traumatized the American people or that watching them on television exacerbated their negative effect.
Respondents were provided with a list of 32 specific events, asked whether they had ever experienced any of them, and if respondents experienced more than one, which was the "worst event" that they'd ever experienced. The list included 12 events indicating exposure to a terrorist attack and the last question concerned virtual exposure: "Did you see or witness a terrorist attack even though you did not experience it directly, like seeing it on TV or listening to it on the radio?" And if the answer was "yes," did it happen on 9/11?"
For 7015 respondents, TV or radio exposure to 9/11 was their index event, and of them, 3981 endorsed only 9/11, with 3034 endorsing it has their worst event. Among small number of respondents who had directly experienced 9/11, the probability of PTSD was 10.6%, but among large number who reported only television or radio exposure, the probability of PTSD was 1.3%. Overall witnessing the 9/11 attack indirectly through TV coverage was associated with the lowest PTSD risk of all the events in the list.
One would think that this study should lay to rest the idea that there was substantial mental health effects of 9/11 and of watching the events on TV. But the myth of a virtual trauma is well entrenched in lay and public policy circles, even if not in scientific circles. A future blog will discuss the successful selling of the idea, even if it is a myth. After all, $21 million in federal funds was allocated to provide free counseling for New Yorkers an additional and $131 million was requested for therapist salaries. One survey found that 28% of Americans had been offered workplace counseling after 9/11. Yet, given the low rates of "posttraumatic stress" and its quick resolution, it is not surprising that there was little uptake of these services.
But first, however, I will take up the claim of Silver and colleagues that not only were there substantial negative mental health effects of 9/11 on the American people, these effects registered in increased heart ailments across the nation. Was there an epidemic of heart ailments across America in the wake of 9/01/2001? See my next blog...