The relationship between consciousness and the brain is something which has been pondered upon by a great many people. In The chemistry of conscious states
J Allen Hobson looks at how the question relates to dealing with mental illness. Hobson is an expert on the effects of sleep disorders, and has several interesting case studies in the book. He makes the point that whatever your philosophy, you should treat mental illness by dealing with both the mind and the brain. Hence rather than a having a deep divide between treatment with drugs and with psychoanalysis, it shoudl be recognised that drug treatments are useful in some circumstances, but it's more important to know about a patient's lifestyle.
If you want to know about the chemistry of the brain, there's a bit in this book but it doesn't go into very much detail. Also I found the philosophical part rather disappointing - Hobson starts the book by saying how revolutionary his ideas of consciousness are, but does little to substantiate this claim. However the book improves as it gets on to the case studies of patients and in particular their sleep patterns, their dreams and some whose waking life is dream-like. Although it isn't really a self-help book, the last part of the book does have some useful information on how changes to your sleep patterns can improve your well-being.