Sarah Zabel introduces the topic of depression as an increasingly recognized disorder for which society still has a long path to travel in appreciating this very common problem. She describes the different schools of thought about causation in depression all the way down to the protein level. The reader will find a fine description of brain chemistry and drug functioning. One of the more important passages of the book concerns the biochemical relationships between excess hormones and stress. In it, she gives a clear view of how depression can be thought of in a disease context via a detailed description of the involved and predictable physiology. However, this section is also written at a highly advanced level for a general readership. Her main point – that there is a describable biology very specific to stress (albeit very complex) gets lost in the details.

By way of emphasizing how depression is a clinical illness, in Chapter 4 she gives an anatomically detailed description of what observable differences are present in neural pathways and brain features between depressed and healthy individuals. She points out that progress towards a newer model of depression is coming as much or more from the realm of brain structure as opposed to neurochemistry. Her discussion of how the scientific perspective on depression is gradually shifting from neurochemistry to micro-morphology really enriches the work. In illustrating just how depression must be understood to have a legitimate and defineable niche as a psychiatric pathology, Chapter Nine, subheading “Intrinsic Networks in Depression” is of great value.

The critical flaw in the book is its density and its wordiness. She simply throws too much factual material at the reader per paragraph. It's more akin to a college textbook than one for an interested but general readership. She also packs in a good amount of discourse that has no relevance to her message. I do hope that she considers putting out a 2nd edition. Streamlining the text could let her do for the understanding of depression what Rachel Carson did for the understanding of environmentalism. Furthermore, the book calls out again and again the need for better integration between neurology and psychiatry - a point with which I very much concur.