Get help and get happy!” runs a tagline for one of the new generation of e-counselling services, offering psychotherapy by text, phone and video chat. Except it turns out that getting happy is by no means guaranteed to be therapy’s only outcome. One recent paper (which I found via the excellent Research Digest blog) estimates that, when it comes to cognitive behavioural therapy, 43% of clients will experience unwanted side-effects like distress, a deterioration in their symptoms, or strained family relations. “Psychotherapy is not harmless,” the paper’s authors conclude. It’s useful research. But that conclusion highlights a widespread belief about therapy that gets stranger the longer you dwell on it: why on earth would anyone assume it was harmless in the first place?