_The Risks_ Since therapeutic running appears to be of psychiatric value, it is not surprising that it, like any attempt to heal, may have potential risks. Aside from the obvious potential for sports-related injuries, there is a specific risk: physical addiction. Dr. William Glasser, whose approach to psychotherapy we discussed in the section dealing with reality therapy (Chapter 11), agrees with Kostrubala that therapeutic running is addictive. Glasser calls it a _positive_ addiction, since--unlike the use of alcohol, barbiturates, and opiates--running is constructive and therapeutic.[5] However, like alcoholism and drug addiction, therapeutic running _does_ produce very real withdrawal symptoms if a dedicated runner cannot continue to run, whether temporarily because of an injury or illness, or permanently. Withdrawal symptoms can be surprisingly severe: primarily, strong anxiety and insomnia, but sometimes also restlessness, sweating, weight gain or loss, and/or depression. [5] William Glasser, _Positive Addiction_ (New York: Harper and Row, 1976), Chapter 5. (Chapter 6 of his book is devoted to another positive addiction, meditation.) BIOFEEDBACK _In psychotherapy, especially useful for clients with problems involving anxiety, depression, phobias, and insomnia, who will benefit from learning how to lessen their own tension._ Most of us can draw a relatively clear line between the physiological processes we can control and those we cannot. Unless an illness or accident or handicap interferes, we have voluntary control over many muscles, but there are many that, fortunately, work without our conscious intercession: the heart beats day and night, our lungs fill and empty, our digestive processes are automatic. Except for people who have voluntary control over the muscles that move their ears, we are all more or {212} less equally endowed, and equally limited, in what physical processes we are able to influence. Until the development of biofeedback, there was only one way to extend self-control beyond the normal range: through a disciplined and time-consuming practice such as yoga. Experienced practitioners of yoga claim that studying yoga over a period of years has given them a sense of personal integration and mental centering similar to what we will see in connection with the practice of meditation. Physical and emotional flexibility also seem to result from long-term yoga practice.