The mind and the body are actually a single system. In western cultures, the mind is somewhere in the head and that everything else is body. This dualism can be traced back to Descartes and his writings. This dualism can even be seen in the way health insurance is treated in the United States. Most insurance policies provide much better coverage for "physical" disorders than they do for "mental" disorders. No such dualism ever existed in eastern cultures, and the mind and body are seen as intricately connected and unified.
For instance, researchers at Bangor University in Wales found performance of a mentally fatiguing task prior to a difficult exercise test caused participants to reach exhaustion more quickly than when they did the same exercise when mentally rested. So “resting up” and finding a peaceful mindfulness before a big day of physical activity is likely going to help you feel better and last longer during the day. Also, uncontrolled anger can lead to heart problems. People with problems coping with their anger or aggravation were found to be at ten times heightened risk for future heart arrhythmias than those without such anger problems etc. A study in the US has highlighted that structured physical assessments of patients with schizophrenia are effective in revealing physical illness.
I think the biggest point is that mental and physical health are not separate things. One ALWAYS affects the other. "We now have evidence to support the claim that exercise is related to positive mental health as indicated by relief in symptoms of depression and anxiety." (Daniel M. Landers, research paper)
Simply speaking, mental health parity states that psychological conditions must be treated equivalently to physical illnesses. Traditionally, insurance companies have radically limited mental health benefits. A common practice has been to limit the insured to three or six therapist visits per year....