There is a very useful field of psychology and accompanying book called Human Givens (Joe Griffin and Mark Tyrrell) that I have enjoyed. It's quite long but the writing is very clear, you can definitely pick it up and dip in when you have time. It's in my local library so probably in yours.
The approach is about considering physical and emotional needs as essential to mental health and how not getting our needs met leads to depression, anger etc. It is very up to date on research and new thinking.
One of the co-authors, Mark Tyrrell, has a lot of videos on YouTube which are short but comprehensible and are aimed at both mental health sufferers and counsellors and receive many appreciative comments (he's English thank goodness!).