It is not nonsense. Immune response is affected by a patient's psychological state of mind.
The reason for cancer trials comparing against other cancer drugs has more to do with 1) those trials being part of costly clinical trials that aim for FDA/European approval which needs comparative data and 2) ethic board approvals being contingent on cancer patients not being treated on just placebo in any case.
Also, no such thing as objective pain. The patient may lie about the severity of the discomfort, but if he successfully convinces himself he's feeling better, he is feeling better.
Lastly, most of your sources make no claim such as "no such thing as a placebo effect". If you disagree with claims of strong placebo effects, you may find support for the inverse claim, but that would be "the placebo effect is not strong", not that it doesn't exist in the first place.
For a DIY, if you don't have qualms about that sort of thing, give your ailing grandma a sugar pill some time, tell her it's some leftover pain medication. See for yourself what happens. (Disclaimer: On second thought, don't do this. There could be a significant nocebo effect involved.)
Incidentally, it is an ubiquitous occurance that patients report feeling the effects of medication long before it has even passed their liver. For relief of subjective symptoms, there is no deeper objective level. Compare Tinnitus treatment. As for cause-and-effect: If you give a pill and there is a shift in the patient's subjective experience strictly depending on having taken that pill, that's as much cause and effect as it gets.
Immune response is affected by a patient's psychological state of mind.
I have come across, but have yet to investigate fully, claims that immune response can be manipulated through classical conditioning. One book claims this as a placebo response mechanism. This is a much narrower claim than "affected by a patient's psychological state of mind".
The patient may lie about the severity of the discomfort, but if he successfully convinces himself he's feeling better, he is feeling better.
That was not the case in the acupuncture study mentioned...
TL;DR: I align with the minority position that "there is a lot less to the so-called placebo effect than people tend to think there is (and the name is horribly misleading)", a strong opinion weakly held.
The following post is an off-the cuff reply to a G+ post of gwern's, but I've been thinking about this on and off for quite a while. Were I to expand this for posting to Main, I would: a) go into more detail about the published research, b) introduce a second fallacy of reification for comparison, the so-called "10X variance in programmer productivity".
My agenda is to have this join my short series of articles on "software engineering as a diseased discipline", which I view as my modest attempt at "using Less Wrong ideas in your secret identity" and is covered at greater length in my book-in-progress.
I would therefore appreciate your feedback and probing at weak points.
Most of the time, talk of placebo effects (or worse of "the" placebo effect) falls victim to the reification fallacy.
My position is roughly "there is a lot less to the so-called placebo effect than people think there is (and the name is horribly misleading)".
More precisely: the term "placebo" in the context of "placebo controlled trial" has some usefulness, when used to mean a particular way of distinguishing between the null and test hypotheses in a trial: namely, that the test and control group receive exactly the same treatment, except that you substitute, in the control group, an inert substance (or inoperative procedure) for the putatively active substance being tested.
Whatever outcome measures are used, they will generally improve somewhat even in the control group: this can be due to many things, including regression to the mean, the disease running its course, increased compliance with medical instructions due to being in a study, expectancy effects leading to biased verbal self-reports.
None of these is properly speaking an "effect" causally linked to the inert substance (the "placebo pill"). The reification fallacy consists of thinking that because we give something a name ("the placebo effect") then there must be a corresponding reality. The false inference is "the people who improved in the control group were healed by the power of the placebo effect".
The further false inference is "there are ailments of which I could be cured by ingesting small sugar pills appropriately labeled". Some of my friends actually leverage this into justification for buying sugar in pharmacies at a ridiculous markup. I confess to being aghast whenever this happens in my presence.
A better name has been suggested: the "control response". This is experiment-specific, and encompasses all of the various mechanisms which make it look like "the control group improves when given a sugar pill / saline solution / sham treatment". Moreover it avoids hinting at mysterious healing powers of the mind.
Meta-analyses of those few studies that were designed to find an actual "placebo effect" (i.e. studies with a non-treatment arm, or studies comparing objective outcome measures for different placebos) have not confirmed it, the few individual studies that find a positive effect are inconclusive for a variety of reasons.
Doubting the existence of the placebo effect will expose you to immediate contradiction from your educated peers. One explanation seems to be that the "placebo effect" is a necessary argumentative prop in the arsenal of two opposed "camps". On the one hand proponents of CAM (Complementary and Alternative Medicine) will argue that "even if a herbal remedy is a placebo, who cares as long as it actually works" and must therefore assume that the placebo effect is real. On the other hand opponents of CAM will say "homeopathy or herbal remedies only seem to work because of the placebo effect, we can therefore dismiss all positive reports from people treating themselves with such".
I don't have a proper list of references yet, but see the following:
http://www.sciencebasedmedicine.org/index.php/behold-the-spin-what-a-new-survey-of-of-placebo-prescribing-really-tells-us/
http://www.sciencebasedmedicine.org/index.php/the-placebo-myth/
http://www.skeptic.com/eskeptic/09-05-20/
http://www.skepdic.com/placebo.html
http://content.onlinejacc.org/article.aspx?articleid=1188659
http://www.ncbi.nlm.nih.gov/pubmed/15257721
http://www.ncbi.nlm.nih.gov/pubmed/9449934