Yoga (Sanskrit, Pāli: योग yóga) is a physical, mental, and spiritual discipline, originating in ancient India. The goal of yoga, or of the person practicing yoga, is the attainment of a state of perfect spiritual insight and tranquility while meditating on Supersoul. The word is associated with meditative practices in Hinduism, Jainism and Buddhism.
The Sanskrit word yoga has the literal meaning of “yoke”, from a root yuj meaning to join, to unite, or to attach. As a term for a system of abstract meditation or mental abstraction it was introduced by Patañjali in the 2nd century BC. Someone who practices yoga or follows the yoga philosophy with a high level of commitment is called a yogi or yogini.
Yoga has also been studied as a treatment for schizophrenia. Yoga is found to improve cognitive functions and reduce stress in schizophrenia, a condition associated with cognitive deficits and stress-related relapse. In one study, at the end of four months those patients treated with yoga were better in their social and occupational functions and quality of life.
Long-term yoga practitioners in the United States have reported musculoskeletal and mental health improvements, as well reduced symptoms of asthma in asthmatics. Regular yoga practice increases brain GABA levels and is shown to improve mood and anxiety more than other metabolically matched exercises, such as jogging or walking. Implementation of the Kundalini Yoga Lifestyle has shown to help substance abuse addicts increase their quality of life according to psychological questionnaires like the Behavior and Symptom Identification Scale and the Quality of Recovery Index.
Source and References http://en.wikipedia.org/wiki/Yoga