Here is a list of books that may be useful to you.
Why We Sleep, by Matthew Walker. (2017)
“Sleep is one of the most important aspects of our life, health and longevity … every major disease in the developed world - Alzheimer’s, cancer, obesity, diabetes - has very strong causal links to deficient sleep.” (From the book cover.) Chapter 7 "deals with the ... consequences of inadequate sleep on the brain." (p.133)
Not in Your Genes, by Oliver James. (2016)
“...Oliver James uncovers the truth about what the science of genetics has proven: that our genes actually play little part in shaping who we are. In fact the latest evidence suggests that nearly all of the psychological differences between us are caused by our upbringing and environment.” (From the book cover.) This means that mental illness is largely not genetic, and can be treated.
Gut, by Giulia Enders. (2014)
Among other things, this book explains the connections between the gut and the brain, via the vagus nerve. This has implications for anxiety, depression and irritable bowel syndrome.
Why Love Matters, by Sue Gerhardt. (2004)
“Sue Gerhardt explores how the earliest relationship shapes the baby's nervous system. She shows how the development of the brain can affect future emotional wellbeing ...” (From the book cover.)
How to Choose a Psychotherapist, by Neville Symington, Joan Symington, Andrew Symington and David Symington. (2003)
This is a very useful short handbook for anyone considering psychotherapy or counselling. You might find the cartoons and line drawings patronising, but the text is useful.