Taking into consideration the other comments on this book (on GR), one needs to understand that unless you've been there, the book will mean little to you. If anything, here's a lesson in keeping secrets: Just don't do it. Secrets are harmful.
The book must've been hell to write, because it meant going back on old details which are often better forgotten - so hats off to Leatham! Another (related) aspect, is that although one might be aware of her thoughts, she does focus on the actions: the reader knows (or maybe I was aware of it) that details have been omitted. For her to have moved and moved and moved and possibly been drunk or slept with someone, are details that are glossed over in order to focus on the self mutilation. I accept the possibility that "outsiders" to this phenomenon are horrified by the act and that Leatham really seems to have had a real go at herself (needing stitches, etc.). It's possible that this aspect had to be the focus in order for the publisher to be convinced to accept the manuscript. Self mutilation is not an act in and of itself. It's but one symptom in a web of others that make up depression (I believe anorexia is also a sub-category of depression, as is insomnia). So, Leatham might've chosen it as the "be all and end all" of her stay in mental institutions and seeing psychiatrists, but it flows from deeper things. Things that she only starts discussing in the final quarter of the book, i.e. the power of the mind and cognitive behaviour therapy. Let's face it: why did she take so many precautions during the act? We're talking clean blades, towels close at hand and she was also checking that there was a doctor, friend or other kind of help nearby. Suicide never entered her mind, nor that it was the clichéd 'cry for help'. This was an act in self protection because her thoughts were driving her up the wall. In order to end that torment and be more comfortable, she gave in. This is something that a lot of her psychiatrists seemed to have missed - she wanted to live happily and this was just a strange way of finding the answer. Once she realized that happiness is not equal to cutting, things changed.
That said, depression is akin to diabetes in the sense that one needs an anti-depressant/insulin to function normally. As long as the individual is able to admit that it's self hurting self as opposed to "some force" invading the self (or as Leatham repeatedly states, "this 'thing' happening to me - no, it's you doing it actively), the road to recovery is short.