Thanks for the link, Cort. But that evidence is not what it is dressed up to be. First of all, that "lots of evidence" is as interpreted in a single review article by two psychologists (no immunologist, for example) of 14 RCT trials. Unfortunately, the real story behind the surface sheen is far less interesting than it might at first have appeared. There are several problems:
Inability to demonstrate improvements specific to CBT
From Carrico and Antoni: "The Effects of Psychological Interventions on Neuroendocrine Hormone Regulation and Immune Status in HIV-Positive Persons; A Review of Randomized Controlled Trials"
"Cognitive-behavioral interventions for HIV-positive persons are efficacious in reducing negative affect when compared to wait-list or treatment as usual controls (32-45). However, cognitive-behavioral treatments for HIV-positive persons have not demonstrated superior efficacy in reducing negative affect compared to other interventions (e.g., interpersonal therapy) or semi-structured social support groups (33, 35, 46)."
That was my major concern when you mentioned this; that there would be no clear way to differentiate between CBT and more 'conventional' therapies or counseling. This has been the same issue brought up again and again in critiques of CBT for CFS, including in the Canadian Consensus document.
They cherry-pick, and are quick to dismiss negative studies:
Of the 14 trials they reviewed, only 6 showed the improvements that they highlighted. They attempted to dismiss the other 8 for various reasons, some very shaky. In order to get more positve studies they suggest that:
Future RCTs should closely attend to inclusion criteria in order to enroll cohorts that are more likely to display changes in HIV disease markers that may be linked to intervention-related effects on psychological adjustment
(so their reaction to some of the negative studies is "well, we just need to find disease markers that will respond to psychological intervention to prove that psychological intervention can affect disease markers"???)
Bad methodology of reviewed trials
"The vast majority of RCTs did not include attention-matched control conditions. Without an attention-matched control, it is
difficult to determine whether the effects are specific to these interventions or non-specific effects of any psychological treatment.
There are numerous methodological limitations of the RCTs reviewed above. The major limitation is the lack of clarity regarding the active element(s) of these multi-modal interventions."
In other words, they used interventions with a combination of Cog. Therapy, relaxation techniques, positive thought techniques, etc., and can't tell which techniques made the differences they reported!
"Future efficacy trials of psychological interventions for HIV-positive persons should also attempt to improve upon the numerous methodological limitations that are evident in RCTs that have been conducted to date. Most trials examined the effects of psychological interventions with small samples and it is possible that many did not have the power necessary to detect effects on immune status. However, effect size estimates for the six RCTs that included sufficient descriptive data to compute this statistic generally indicated a lack of intervention effects on CD4+ counts (Cohen’s d range = -.77 to .31; Median = -.17). Because of the heterogeneity of other HIV disease markers examined, it was not possible to calculate reliable estimates for the effect size range."
In other words, only six of all the trials they reviewed found what they deemed to be significant changes in disease markers, and even among these it was not possible to assess these improvements quantitatively with any accuracy due to the number (and type, I assume) of variables they were looking at.
Their CONCLUSION...
"Finally, despite the past 20 years of research to develop and test the efficacy of innovative psychological interventions for HIV-positive persons, there is insufficient data regarding the clinical relevance and policy implications.
Effectiveness trials of promising psychological interventions with more representative samples of HIV-positive persons in varied settings are needed to provide more definitive information on the clinical utility of these treatments and their potential cost-effectiveness."
i.e. we think we have evidence (though some others in our field disagree with us), but it is insufficient right now; things are still in the research stage, and definitely not ready for implementation by doctors in the real world.
Also, here's the abstract from a paper they themselves cite as 'cautionary' to this area of research; it's worth quoting in full:
Miller GE, Cohen S. Psychological interventions and the immune system: a meta-analytic review and critique.
"This article reviews evidence for the hypothesis that psychological interventions can modulate the immune response in humans and presents a series of models depicting the psychobiological pathways through which this might occur. Although more than 85 trials have been conducted, meta-analyses reveal only modest evidence that interventions can reliably alter immune parameters. The most consistent evidence emerges from hypnosis and conditioning trials. Disclosure and stress management show scattered evidence of success. Relaxation demonstrates little capacity to elicit immune change. Although these data provide only modest evidence of successful immune modulation, it would be premature to conclude that the immune system is unresponsive to psychological interventions. This literature has important conceptual and methodological issues that need to be resolved before any definitive conclusions can be reached."
Finally, the study you quoted on CBT for preventing neoplasias:
That is a single paper with a total of 21 test subjects.. and they do not make the presumption you did (at least, not in the abstract); they made no claim of absolutely enhanced immune function, but rather relative enhancement via stress reduction for a chronically stressed, low-income population. Plus you'd have to see the data behind their "odds" calculation before buying their conclusion, as nothing of that is explained in the abstract.
So we're back to the same old place.. there are a lot of negatives and a few promising maybes and
maybe one good lead in CBT research on a given disease,
but (1) the evidence remains unclear, (2) the samples are small, the trials very few in number, and (3) studies are preliminary and research is at best in its early stages, definitely not ready for clinical endorsement. And I happen to find these trials more convincing than the ones on ME/CFS! So why is CBT a prominent (or THE prominent in many places) treatment suggestion for CFS?? And sure, reducing stress and depression can help improve the quality of life (and probably the immune status) of people with a number of diseases... but you don't need specifically CBT for that, as even the authors of the review you quoted clearly pointed out; interpersonal therapy, relaxation techniques by themselves, etc., when they improved an individual's mood, all seemed just as helpful as CBT.
So why push this particular therapy, that among other things challenges your 'beliefs' about illness? Answer: it's faster, and therefore more cost-effective, and it also promises a model of rehabilitation as opposed to chronic treatment, so disability insurers (private or government) love the idea.
And yet again, why do so many of us have a big problem with it?
Because: (1) the graded exercise/activity component of most popular regimes ignores physiological reality and (2) the false illness belief ideology central to most models of CBT has so deeply embedded the belief in the clinical (and econo-medical) consciousness that most of us are less sick than we 'think' we are, that no amount of Klimases and the like will be able to rehabilitate the concept... leading to continued abuse and neglect of a majority of PWC by their government and private institutions as well as by their doctors and families. For CBT, justly or unjustly, is the major entry point for the psychosomatic school of 'thought' into the redefinition of our illness, and that is a reality and a danger you (and we all) must face.