A lot of people like to think of it in terms of linear relationships. The way I see it is that something is causing metabolic dysfunction in a person's body or brain. Smoking cigarettes, even though they're thin, can cause insulin resistance and type two diabetes. Smokers are also more likely to develop every other mental disorder,. all the way from anxiety to depression to bipolar to schizophrenia. Anything that is toxic to mitochondria can result in these different metabolic problems.
Christopher Palmer, MD, is the Director of the Department of Postgraduate and Continuing Education at McLean Hospital and an Assistant Professor of Psychiatry at Harvard Medical School. For over 27 years he’s held administrative, educational, research, and clinical roles in psychiatry. His new book, Brain Energy: A Revolutionary Breakthrough in Understanding Mental Health—and Improving Treatment for Anxiety, Depression, OCD, PTSD, and More, is out now.