In our modern world of packaged foods, most people fail to intake the necessary micronutrients required for adequate brain function. This alone can leave people feeling strung-out, unable to focus, anxious, etc. There is now more than 20 years of research (originally pioneered by Bernard Gesch of Oxford University) showing the importance of adequate diet for good mental function. As our emotions are strongly influenced by brain chemistry, and as brain chemistry is strongly influenced by diet, a great many people who presently self-medicate with a variety of unhelpful substances could find themselves far better aided by means of commencing a better diet rich in omega-3 acids (fish oil), B vitamins, zinc, magnesium, and various other essential micronutrients. The BPNRC at University of Northumbria has published a variety of papers on this topic and is thus an excellent resource for anyone wanting to learn more. And no, I don't work there!