Yoga has a beneficial effect on most disease states; but first, disease has to be defined properly. Yoga has its own definition. Disease manifests in the body but does not originate in the body; disease originates from a state of imbalance. There may be disharmony between the nervous systems or an imbalance in the hormonal secretions, or in the digestive processes. As such, disease is defined in a subtle manner, and treated according to its nature.
For example, yoga does not treat diabetes as a digestive disorder. It is known to be a deficiency in insulin, there is no doubt about it. It is also known that the sympathetic and parasympathetic nervous systems are controlled by higher centres, and when these centres fail to activate the nervous system properly, a deficiency of hormones in a particular area results. When yoga treats a diabetic patient it is not a treatment for a deficiency of insulin; he is not treated for the disease he is apparently suffering from. Yoga recognizes that it is stress and strain that are responsible, so the treatment is for that.
When a mental health patient suffering from psychosis, neurosis or a nervous breakdown is treated, yoga takes him as a personality, a human being, an individual who can think and feel. Yoga takes him deeper into his own mind through the practices of concentration and meditation, bringing him to the root of his illness.
If a person is suffering from high anxiety, the prescription is not for practices that induce an immediate state of tranquility. Rather, yoga tries to explode that person’s personality, to express what remains dormant in the back of his mind. This is possible with the practice of concentration, such as mantra, which is part of yoga. As a scientific principle, mantra is a powerful instrument. Through the practice of mantra, one tries to explode the deeper phases of the consciousness. When the inner states of mind are exploded then one comes face to face with all the thoughts, distractions, passions and repressions that lie deep within.
The physical body is influenced by the human mind. It is the sentiments, the emotions, feelings and objectives, passions, fears, anxieties and worries in the mind which create physiological changes in the body. The adrenal, thyroid and pituitary secretions have a natural flow and order. A thought can and does influence the working of the physical body. Fear, psychosis or anxiety influence the endocrine glands and change the mode of brainwaves.