Yes, that's probably the best description of this sort of unrelated cause and effect. Woolie, how much do you think the null hypothesis is respected in psychology related trials? Do treatments like that actually have proper trials?
No. The vast majority don't control for the sorts of biases I was talking about above.
I think when it comes to Psychology interventions, effectiveness studies are of amazingly poor quality. Only some include a control (no treatment) group, and often this control group is inadequate. It might just be a bunch of people on a waitlist for later treatment (so they'd have no expectation of recovery, and might even be a bit annoyed about being kept waiting, so this doesn't control for the placebo effect). Or it might be a "treatment as usual" group - they visit their doctor every now and then, but no change from what was happening before. This type of control condition still doesn't deal with placebo effects/bias.
I'd start to take a study seriously, if the control condition:
- required the same level of commitment from participants as the condition of interest (attendance, "homework", etc)
- provided the same expectation of improvement
- was presented to patients as positively as the treatment of interest
Some examples might be relaxation therapy, yoga, coping skills workshops etc.
Another way around the problems of bias, if you couldn't set up a suitable control condition, would be to use some sort of objective measure of improvement - for example, fitness levels, physical activity levels, attendance at work, etc. These might be less susceptible to bias. You could use measures based on the judgements of another observer (e.g., ratings of movement fluidity) but only if the observer was blinded to the treatment condition. Otherwise, again, there would be bias.
A lot of Psyc studies also exclude people willy-nilly to make their results look better. For example, they might exclude people who withdraw from a treatment early. You can imagine that many people who don't sense any improvement might withdraw early, especially if they're ill and the treatment involves a lot of travel, effort, etc. By excluding these people, it makes the results look much better than they actually are. If 5% or more of the participants withdrew, then this is a serious concern.