Imagine a person, physically and mentally healthy, totally satisfied with life. Though an ideal picture, this image, if real, would be of a person who has their hormonal and neurotransmitter systems in a balanced state. The neuroendocrine balance is reflected by an appropriate feedback between sympathetic and parasympathetic systems in this person.
Physiologically, the balance of various systems within the body can be understood on the basis of electromagnetism (e. g. ECG, EEG), or levels of elements, hormones, enzymatic secretions or metabolic products. Whenever their levels become abnormal, the body tends to become imbalanced in certain predictable ways causing a state of illness. Physical conditions can be measured in above terms. But measurements of mental conditions were till recently unacceptable in the above terms.
Depression is a mental condition (also having physical effects) in which a person is unhappy, with loss of concentration, energy and ability to enjoy life. There is an accompanying obvious physiological imbalance in the body systems. Autonomic disturbances and increased levels of cortisol are characteristic features of depression. Depression is a state of stress in which the body (and the brain) is uncomfortable. This discomfort is due to a “perceived" threat to the body or a part of the body. In the course of Nature, the body and mind would like to “undo" the effects of “perceived threat". The sympathetic part of autonomic nervous system plays a more active role in “undoing perceived threat. "
With sympathetic arousal, the senses of perception – like hearing, vision, taste, touch and smell – become sharper. The sensory input to the brain increases. Constant bombardment of the brain through stimulations from hypersensitive senses, creates “information overload" of the brain. We perceive this condition as stressful. In depression, this perception is as a result of conditioned responses to sensory cues. These responses generate characteristic physiological responses in other systems in the body, as experienced by a depressed individual.
Other than treating the consequent neurotransmitter imbalance with antidepressants, cognitive therapy can help a depressed person change body's physiological responses. Meditational practices are also helpful. They sometimes involve “doing nothing" physically and mentally. This process of switching off physically and mentally even for a short time cuts off the sensory stimuli that reach the brain in depression, creating sensory overload. This relaxes the nervous system. This relaxation is transmitted to the other systems of the body, that respond with creating a further state of relaxation. As the sympathetic tone is diminished, the parasympathetic tone increases, creating a balance between the two. Emotional arousal can also occur when a depressed person relaxes. This arousal sometimes needs active therapy before the balance in physiology can be established. Treatment methods to diminish this arousal are beyond the scope of this article.
All meditative practices tend to slow down body's metabolic activities by directly or indirectly affecting hypothalamo-pituitary-adrenal axis. As catabolism, resulting from stress diminishes, anabolism increases. This is mediated by corresponding and spontaneous parasympathetic stimulation. Slowing down of heart rate, lowering of blood pressure, boosting of immune system, glycogenesis and lowering of cholesterol levels in blood tend to occur.
Some meditative practices involve breathing exercises. They usually involve repetitively taking in a deep breath and exhaling slowly. This activity in itself reduces the workload of the lungs. Air inhaled in the lungs in one deep breath (Inspiratory Capacity = 3.5 litres) is equal to seven normal breaths (Tidal Volume = 0.5 litres). Each deep breath slows the flow of blood in the pulmonary vein, which slows down atrial filling and subsequent ventricular filling. This slows down the heart rate without affecting cardiac output adversely. With deep breathing, stretch receptors on the lungs stimulate afferents to vagus nerve. Efferents from vagus nerve to the heart further slow down the heart. Peripheral vessels are dilated as a result. This lowers the blood pressure. Consequently, the physiological responses of other systems in the body slow down. The hypothalamo-pituitary-adrenal axis perceives the situation as a non-stress situation. As such, ACTH secretion diminishes. This explanation is a simple outline of the mechanisms involved.
Prayer and spiritual practices have long been known to be effective destress techniques. The physiological mechanisms were not understood till recently. Recent advances have shown the efficacy of religious practices in maintaining physical and mental health. Larry Dossey has described double blind studies with prayer in his book “Healing Words". More recently, Candace Pert, a physiologist has confirmed the positive effects of meditation in maintaining good health, especially by affecting the heart, the immune response and neuropeptides. There have been many other researches in this area, which have clinically shown the positive effects of spiritual practices on human health. The future of psychiatry is in offering treatment with limited medication.
(References available on request).
Pradeep K Chadha is a psychiatrist who specialises in helping patients with meditation and imagery using little or no medication. He is the author of The Stress Barrier-Nature's Way To Overcoming Stress published by Blackhall Publishing, Dublin. He is based in Dublin, Ireland. His website address is :http://www.drpkchadha.com