"Pradnyaparadham hi moolam roganam"
In the words of Charak, all diseases originate from pradnyaparadham (foibles of human thinking), while in the words of Patanjali, yoga is restraining the fickle tendencies of mind.
"Yogaschitta vritti nirodhah"
This yoga means withdrawing the extrovert tendencies of mind from mundane objects, making them introvert and merging them with the basic background of mind. The entire universe (nature) is the product of three qualities of temperament: sattva, rajas and tamas. The state of concentration which is illumined by the light of truth when chitta (the base of mind), is purged of tamas (its envelope of darkness) and of rajas (the fickleness of mind) is yoga.
According to ayurveda, rajas and tamas are the root causes of all mental diseases. They produce desire, anger, avarice, temptation, jealousy, fear, excessive worry and mental weakness. These foibles of human thinking are positively at the root of mental diseases.
"Irshya shoka bhaya krodhah mana dveshadayascha ye sarva pragnyaparadhah"
The passions are all caused by the errors of thinking. It is one's foremost duty to avoid these in the interest of mental health.
The best way to free oneself from desires is limiting the needs of life, particularly excessive comforts, luxuries, and possessions. The man dwelling constantly on the sense objects develops attachment for them. Desire springs from this attachment. From the least unfulfilled desire ensues anger, from anger arises infatuation, that is, ignorance about what to do and what not to do, which causes confusion of memory. Confused memory leads to forgetfulness of what causes harm and which behaviour leads to such harm. Ignorance in these matters leads to repeated mistakes. That is called the loss of memory. From loss of memory one loses reason and directly goes to ruin.
Purity of mind comes from purity and cleanliness of diet. Memory, that is reason, is regulated and balanced thereby. Purified intellect enhances knowledge of self and thus mental complexes are controlled. Besides regulated diet, for mental health, mind should be brought under control and that is all important. Mental control enables one to get rid of attachment, to worldly objects especially, and is attainable through righteous conduct.
A sound mind is the cornerstone of sound health. It would be a folly to imagine a sound body in the absence of a sound mind. Mind is certainly the principal director of bodily activity. Body is only the envelope of the mind. Certainly the mind reflects itself on the body. That is why the shape and condition of haughty, greedy and jealous persons is distinctly marked out. A peaceful mind is bound to have a healthy body, so for excellent physical health, excellent mental health is indispensable.
Today, psychiatrists all over the world accept the truth of all that has been stated above. Modern medicine now considers 90% of diseases as psychosomatic, while previously this was regarded as only one of many causes and adequate importance was not attached to it.
In the last few years, after extensive research in the matter, it has come to medical notice that the majority of diseases result from restlessness of mind. American physicians have concluded that a peaceful mind is absolutely necessary for a sound body. This is why, in the field of medicine, satisfactory results are not obtained for psychosomatic diseases, while through yoga practice the solution is readily obtained. This accounts for the popularity of yoga in many countries of the world. No one can belie its importance today.
We should constantly practise contentment, regularity and restraint in our daily routine in order to maintain equilibrium of mind. The best method for this is found in Patanjali's system of yoga, which enables us to attain physical, mental and spiritual progress and the principal aims of human life - righteousness, prosperity, attainment of desires and salvation.