This was the second book that was due at the library just after Christmas, and I admit I raced through it in order to be able to return it just in time. Phew. Overall I found it to be well-written, although there were a few chapters that ended rather abruptly, one sentence I couldn't parse without mentally deleting a world, and possibly a few extra (unnecessary?) details in some of the chapters.
But all that didn't really distract from the main message of the book, which basically boils down to a re-examination of the drug trials done on depression medications and what studies have shown about the causes of depression and how they tie into life events. One of the things that Hari tries to show through his various studies and examples is that although antidepressant medications do help in the short term by alleviating symptoms, depression isn't just broken brain chemistry that can be reset by a pill. If you follow that thinking, then you risk going down the rabbit hole of higher and higher dosages and swapping medications until you find one that works for you...until you need to switch again. He goes on to explore how different types of emotional disconnection and trauma can be a precipitating factor in depression and discusses different forms that therapy can take (gardening, meditation, etc).
Anyway, I thought it was quite interesting, and I would recommend it to anyone interested in the topic. Hari does talk about his own experiences and describes many therapy stories that he's come across in his research, but he also relies a lot on a range of studies on both drugs and mental health in general.