I don't see that much wrong with this paper by Esther Crawley et al, and welcome more research on comorbid depression in ME/CFS. I am one of the ~30% of patients that unfortunately does suffer from comorbid depression, and I can tell you it is a bugger to treat. I have trying for years to find some effective treatments. A
poll on this forum found that 37% of ME/CFS patients are depressed.
Like my ME/CFS itself, I am pretty sure my depression is
not psychogenic; it does not result from my more limited life circumstances under ME/CFS; my depression is definitely neurologically caused.
Normally those with depression have recourse to exercise, which is known to raise mood, likely via an endorphin mechanism. But in ME/CFS you don't have recourse to exercise, for two reasons:
Firstly because many ME/CFS patients will get PEM after exercise, so exercise is pretty much out of the question in these cases.
Secondly, even for patients like myself that do not get much PEM from physical exercise, it is well known that in ME/CFS you lose the normal mood boosting antidepressant of exercise. So even if you can do exercise, it does not really help your depression.
I can definitely confirm this: before developing ME/CFS, I always found a strong mood boosting effect from exercise, even from just a 15 minute jog, and I loved doing exercise for this very reason. But now with ME/CFS, it does not matter what type of exercise I do (running, brisk walking, going to the gym and doing weights), there is very little improvement in mood.
I think the comorbid depression in ME/CFS may be a particular form of depression that is hard to treat. It may be linked to some dysfunction in the endorphin system (a couple of studies have found endorphins low in ME/CFS: refs:
1 2).
It is interesting that in
Crawley et al's review, they state that
one study found "significant improvements in CFS/ME and depressive symptomatology in response to S-citalopram", as well as improvements in PEM, headaches, un-refreshing sleep and impaired memory and concentration from this drug. S-citalopram is otherwise known as
escitalopram (Lexapro), which is an antidepressant and anti-anxiety drug I have not yet tried. I'll have to try escitalopram (although I am wary of SSRIs, given that when I tried citalopram, it
massively increased my depression levels).
It is interesting that escitalopram
has been found to reduce pain levels in patients taking opioid pain medications. That perhaps suggests that escitalopram might work on the opioid and endorphin system.
Also of note is that this review mentions antiviral treatment of ME/CFS using valacyclovir was observed to reduce depression symptoms (but treatment regimens were 3 to 60 months long).
I have to agree with Prof Norman Booth's criticism that the issue of comorbid depression needs to be tackled in terms of understanding the underlying biology and pathophysiology. I think psychologists would do well to team up with neurologists, immunologists and biochemists when studying the neuropsychological symptoms or neuropsychological comorbidities of ME/CFS.