Hi Jenny
I've been often disappointed with the quality of evidence I have seen in published psychological trials but as you say this may just be because the really rigorous research does not often filter down to the public. I'm genuinely curious, would you be able to explain a bit about how a psychological intervention such as CBT for treating ME could be properly assessed, what tools and methods could be implemented to effectively control for the many sources of experimental bias and placebo that are present in un-blinded trials.
Hi wdb
Yes, often the quality of evidence in trials of psychological interventions is poor. But my point is that that is also often the case in medical trials too. It's quite difficult to evaluate the effectiveness of many psychological interventions as, as you imply, you can't usually have a control group who is receiving a placebo. The best you could do
perhaps is have say three groups of patients, matched for say age, sex, length and severity of illness. Group 1 would have CBT for one hour a week for say 12 weeks. Group 2 would have a supportive chat with a psychologist or other practitioner one hour a week for 12 weeks, and Group 3 would have nothing.
All patients would be assessed at the start (time 1) and at the end of 12 weeks (time 2) and say 6 months after the end of the trial (time 3) by someone independent from the therapist on several criteria:
Self-reports of symptoms and quality of life using an instrument with good evidence for reliability and validity. I haven't seen anything yet that is much good, so something would need to be developed (that would be quite an enterprise though).
Actual activity perhaps using an actomer for a period of time.
Immune system parameters like NK cell activity etc (CBT therapists often claim their treatment improves the immune system!)
The main hypotheses tested would be that there are significant improvements between time 1 and time 2 on all measures for Group 1 and no change for Groups 2 and 3. These improvements continue to time 3.
There are of course lots of potential weaknesses in such a study, for example:
Group 1 may know they're having the 'treatment', so any improvement could be due to the placebo effect. But Group 2 might also think their supportive chat is treatment, so this may to some extent control for this. Any placebo effect is unlikely to last 12 months though.
Unless all have the same therapist, some might be better than others.
etc ,etc
But there is no such thing as a perfect study.
(Perhaps I should say that I think there is absolutely no place for psychological interventions (or for psychologists) in treating ME, except perhaps to support people in distress from having such a terrible illness. And I haven't seen any study that shows that CBT is an effective treatment for ME.)
Jenny