Art of healing, by the mind. These include Yoga, hypnotism, meditation, etc. Sigmund Freud developed psychoanalysis about 100yrs ago. It involves special counselling, drawing out personal troubles (which he believed were the root cause of {depression} & illness). As with most psychological therapies, the patient often experiences a sense of release & find their health improves.
These treatments are most effective with {stress} related illness or for addictions (e.g. smoking, drugs, alcohol). Additionally, when used as a preventive measure against stress & life pressures, they can also improve lifestyles & thus prevent illness.