But it’s not PTSD! Bad research distorts our understanding of a serious disorder.

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1044810_10151728883522755_1792348626_nThe diagnosis of posttraumatic stress disorder (PTSD) was originally limited to persons who had faced a horrific situation outside the range of normal human experience. Their ability to function also  had to be impaired from a distinct clusters of psychological symptoms that they had developed in response to that situation. Eligible experiences included natural and man-made disasters and acts of violence including military combat, atrocities against civilians, and rape.

Acute and chronic physical illnesses and health events were at first excluded from being considered as causes of PTSD. Such events might involve realistic threats of death, but were not presumed to precipitate a serious and persistent mental disorder.

There was also a stubborn conceptual and assessment issue behind excluding illness and health events: A diagnosis of PTSD required that the events that were associated with PTSD be securely in the past. For instance, the World War II veterans whom my colleagues and I studied had survived the Bataan death march with experiences that we could hardly imagine. When we assessed them, the veterans knew well that they no longer had to fear Asians, starvation or poisoning from rotten food, or being forgotten in the jungle. They knew that they could get up in the middle of the night to go bathroom without a guard beating them or being bitten by venomous creatures. Yet, over half century later, they suffered hypervigilance, flashbacks, nightmares, and avoidance of things that reminded them of their experiences.

Medical events such as a diagnosis of cancer or a stroke can convince people that  their life will be shorter than they had thought just before the event. But lives being changed by a medical event is qualitatively different from veterans’ sense of being changed forever by the degradation and dehumanization they faced at the hands of their captors or for a rape victim, at the hands of a rapist. Persons who have just suffered a life threatening medical event are understandably upset immediately afterwards. Vigilance and hypersensitivity to bodily sensations may be quite appropriate and adaptive responses. Some of these bodily sensations are novel and threatening, having had their onset with the medical event. Or they could be signs that they need to promptly seek medical attention. Ignoring them could be difficult or maladaptive.

Over time, most persons having had a medical event will adjust. Their initial emotional reaction subsides, even if bouts of anxiety, as well as realistic concerns and self-monitoring continue. Distinguishing normal from abnormal may make sense in the abstract, but there are sometimes challenges deciding between normal reactions and abnormal reactions warranting mental health interventions. Professionals do not wish to leave persistent and debilitating psychological reactions unaddressed, especially if they would respond to treatment. Yet, there is also a wish to avoid turning normal reactions into a mental disorder or for mental health professionals to interfere with the normal reactions in ways that might be counterproductive and even harmful.

The 1994 revision of the Diagnostic and Statistical Manual and subsequent versions removed the exclusion of acute and chronic illness and health events as possible causes of PTSD. The DSM did not specify that these events were necessarily traumatic, but raised the possibility that research could show that these events could indeed precipitate of PTSD and that mental health treatment reduced symptoms and improve functioning.

Cancer was expected to become the paradigmatic example of a disease which could prove traumatic and precipitate PTSD. Yet, as I showed in a previous blog post, quality research using diagnostic interviews does not reveal particularly high levels of PTSD among persons who have been diagnosed with cancer. Rates of PTSD often differ little from age-matched persons drawn from the general population who have not been diagnosed with cancer.

A diagnosis of PTSD is unique among mental disorders because it requires not only having a list of symptoms, but (a) exposure to an extraordinary event, (b) a reaction of intense fear, helplessness, or horror: (c) a minimal number of symptoms in each of a number of clusters: recurrence, avoidance, and arousal; (d) that these symptoms were not occurring before the event; and (e) the person is impaired in functioning specifically by these symptoms and not by other aspects of the event, like physical injuries. Many of the symptoms that could contribute to a diagnosis of PTSD are quite nonspecific expressions of distress, and could easily be part of another disorder like major depression or even a symptom of a physical condition or side effect of medical treatment. Confirming the diagnosis requires careful interviewing, establishing that all criteria a-e are present, and ruling out alternative explanations of symptoms. Yet, the relaxing of the rules for diagnosis of PTSD yielded lots of poorly conceived studies that did not involve careful assessments of these criteria, but relied only on patient endorsing symptoms and complaints on checklists.

All someone now needed to become a PTSD researcher was simply to have access to a clinical population and a checklist. That does not take many resources, but also does not involve researchers interacting much with patients in ways that might dispel the notion they were suffering from PTSD. What would otherwise be an uninteresting study of short-term distress among cancer patients can be dressed up and dramatized with claims that it is trauma that is being studied. Journals routinely publish insufficiently documented claims that cancer is a trauma and that cancer patients are suffering PTSD or “PTSD-like symptoms.”

The rates of PTSD found in checklist studies of cancer patients exaggerate what is found in better designed interview studies, but there are so many more of poorly designed checklist studies than good ones. An investigator mindlessly combining studies without regard to their quality might conclude that PTSD is rampant. The myth of cancer as traumatic continues to hold sway in psycho-oncology—the study of psychosocial aspects of cancer—where much of the research basically involves misinterpretation of the distress that follows a diagnosis of cancer that is often normal and transient and if not, reflects pre-existing problems.

cbs news ptsdjpgA team of Columbia University investigators seem to be going down the same path as psycho-oncology researchers did, but for cardiovascular events such as acute coronary syndrome (myocardial infarction or angina), transient ischemic attack (TIA), and stroke. These investigators recently published an article in PLOS One that they have followed up with a press release and television and radio interviews declaring cardiac events to be commonly associated with PTSD.  They call for resources for routine screening of cardiac patients and for their research program.

The spot on national TV which you can reach here is carefully crafted. One investigator explains that their meta analysis concluded that PTSD is common among survivors of stroke (1 in 4). Another has prepped the interviewer to ask him about Sam, his grandfather from Alabama, whom the investigator describes as “a mountain of a man with a huge heart.”  This introduces the recommended human element into the promotion without the relevance to PTSD ever really being established. The interview is an example of good marketing of what I will demonstrate in this blog post to be bad science.

Should we revise our understanding of PTSD and expect it to be a common reaction to a stroke? Should we vigilantly monitor survivors of stroke and promptly intervene with the most validated intervention for PTSD, exposure therapy that would involve them re-experiencing  having had a stroke within the safety of a therapy session? These investigators do not make a strong case. There is no evidence that patients would benefit from what could be an uncomfortable therapy experience, and I think many therapists would be uncomfortable with the idea. Maybe provide overly anxious patients after such an event with psychological support and education, but not exposure therapy.

Taking the investigators’ claims seriously could undermine our understanding of a serious and debilitating mental disorder and lead to the offering inappropriate treatment to survivors of stroke do not need it and probably would not benefit from it. What these investigators are attempting to do is more understandable than other researchers who call for marshaling resources to detect and treat PTSD among mothers who have just given birth. But it is just as wrongheaded to allow such “bracket creep” of the diagnosis of PTSD and just as trivializing of the experience of persons who are truly traumatized by combat, acts of terrorism, and rape as when giving birth is declared an experience with a high risk of PTSD.

The Columbia University investigators’ press release states:

Our current results show that PTSD in stroke and TIA survivors may increase their risk for recurrent stroke and other cardiovascular events…Given that each event is life-threatening and that strokes/TIAs add hundreds of millions of dollars to annual health expenditures, these findings are important to both the long-term survival and health costs of these patient populations.

This is a misleading statement because this study did not even investigate whether what they defined as PTSD in stroke and TIA survivors increases the risk for other cardiac events. These investigators are hyping the importance of their work with no evidence to support their claims, only what was known before their study, that strokes and transient ischemic events cost money to treat.

The study found that 23 percent, or roughly one in four, of the patients developed PTSD symptoms within the first year after their stroke or TIA, with 11 percent, or roughly one in nine, experiencing chronic PTSD more than a year later.

And

Surviving a life-threatening health scare can have a debilitating psychological impact, and health care providers should make it a priority to screen for symptoms of depression, anxiety, and PTSD among these patient populations.

The investigators’ article that was the focus of their publicity blitz is available open access here.

What the investigators did

  • Searched the literature and identified 9 studies for inclusion in a meta analysis estimating the prevalence of PTSD in survivors of stroke and TIA.

What they claimed they found

  • That 1 in 4 (23%) survivors of stroke also suffer from  PTSD within one year after the event and 11% after one year.

Where they went wrong

Table 1, reproduced from the paper can be seen below. You can also get a larger, clearer view of the table here.

journal.ponestroke table.t001

As can be seen, studies vary greatly in their estimates of “PTSD,” from low estimates of three, four, and 10% too high estimates of 30 to 37%. Interview studies find only 3 to 10%, with the lowest estimate from careful semi structured diagnostic interviewing. The high estimates of over 30% are found in lower quality studies depending on patients completed checklists. Basically, the better the quality of the study the lower the estimate, and the gap between poor quality studies and high quality studies is so great as to discourage integration of these figures with meta analysis into a single, summary estimate. The investigators’ report of 23% is found in no study, but falls in the considerable gap between the poor and the better quality studies.

One estimate of the prevalence of PTSD depended on responses to the Impact of Events Scale (IES) checklist, which is particularly inappropriate. The IES does not measure PTSD, it was not intended to. The IES does not assess whether a patient reacted with intense fear, helplessness, or horror. It fails to assess symptoms needed for a diagnosis, excluding hyperarousal symptoms altogether and some avoidance and intrusion symptoms. Check out the items here. They are vague and nonspecific and might easily refer to normal responses.  In some circumstances like after a medical event, the items could tap adaptive processes of alternately thinking about how life was now going to be different and deliberately taking a break from focusing on it. The investigators had no business combining estimates of “PTSD” from the IES with estimates from diagnostic interviews.

Another checklist generating estimates over 30%, the Posttraumatic Stress Diagnostic Scale more directly follows symptoms associate with a diagnosis of PTSD. But it as highly correlated with the Beck Depression Inventory (.7) as their respective reliabilities allow. Essentially the PSDS questionnaire is statistically interchangeable with a self-report measure of depressive symptoms and the latter would have produce the same results, which overestimate both the number of clinical diagnoses of depression and PTSD.

As a I noted in a previous blog post

Questionnaires do not provide an opportunity for investigators to explain to patients what is meant by specific questions or to probe patients’ responses in an interview. Most importantly, there is no opportunity to determine the nature of the symptoms or to rule out other disturbance, such as major depression, crucial to the diagnosis of PTSD. Not surprisingly, questionnaires yield a high proportion of false positives when compared to a diagnostic interview.

Regardless, the results obtained with questionnaires suggest that rates of heightened distress among the stroke and TIA patients are no greater than what is typically found in a random sample of primary care waiting room patients, about a third, but most of this distress in patients from both types of settings represents neither major depression nor PTSD.

As for making screening for depression and other mental disorders a priority, the real question is whether it would serve to improve patient outcomes. We examined the question in systematic reviews, one in JAMA, the Journal of the American Medical Association and a follow up in PLOS One.  We found a lack of evidence that introducing depression screening would benefit patients in cardiovascular care.  Recently, the Canadian Task Force on Preventive Health Care retracted its previous recommendations for routine screening with language remarkably similar to another of our systematic reviews of screening for depression, this time for general medical care. The quality of routine care for depression in general medical settings is not good. Improving the quality and intensity of mental health treatment for patients already known to have disorders should be a higher priority than putting more patients into that low quality care.

Despite what these Columbia University investigators claim, the best evidence is that there is not much PTSD among stroke and TIA patients, screening would be inefficient and not likely to have much benefit to patients, and certainly not for the mortality or risk of another event. Much of what these investigators consider PTSD is more accurately described as general psychological distress and not a diagnosable mental disorder. A brief consultation with established PTSD researchers could have explained that to them.

 

 

 

 

 

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