If there is any illness for which 100 treatments are available, you can be sure that none of them works.True. But he doesn't do a great job of addressing why parents swear by such ineffective treatments. His answer is the "Hawthorne Effect". I think there's rather more to it than that. For one thing, Spiesel does not consider the possibility that a treatment might have no effect at all - not even a non-specific "placebo effect" - and still become popular.
But that happens. A PLoS ONE paper, From Traditional Medicine to Witchcraft, tries to explain why. Although it features some maths and lots of graphs, the argument is summed up in a sentence
Superstitious treatments and maladaptive practices can spread because their very ineffectiveness results in sick individuals demonstrating the practice for longer than efficacious treatments, leading to more salient demonstration and more convertsIn other words, the less well a treatment works, the longer it gets used, and therefore, the more likely it is for other people to see it being used and adopt it. Of course this only holds under when people are completely unable to tell whether treatments used by others work or not. This may be a valid assumption.
Psychology Today interviews rebellious British psychiatrist David Healy about his new book, Mania, which I really need to read. Healy notes that bipolar disorder became a fashionable diagnosis starting in the mid 1990s. A while back I plotted a graph showing how often bipolar disorder was mentioned in the British media. It became much more popular after about 2000 - which sort of makes sense.
Healy's one of the few people who manages to be deeply skeptical of much about modern psychiatric diagnosis and treatment while avoiding Tom Cruiseist anti-psychiatry. His last book was a homage to ECT, ferchrisakes. A lot of people felt actively betrayed by that. But if you still doubt Healy's intellect, his use in the interview of a Buffy metaphor to explain the history of "mood stabilizing drugs" should set you straight. Genius.