Pat Corum and his buddies stay in touch by telephone these days. In a way, they are sort of like guys who served together in a wartime POW camp. In a lot of ways, of course, they are very different. For one thing, they're all convicted murderers.

Corum was sentenced to two life terms and spent 24 years and a few months in California prisons, mostly Folsom, the state's maximum-security facility. His first murder, he says, involved a drug deal gone sour. His second, an execution of a fellow convict ordered by gang leaders.

Corum is 50 years old now and has been out of jail -- paroled -- for about four years. He married a corrections officer and is finishing up a pre-law course with a 3.7 grade point average at the University of California at Bakersfield. He plans to go to law school in the fall, although he knows that "with my felony background, there is serious doubt I'll ever get admitted to the bar."

Corum is no pussycat, but his rehabilitation appears to be as radical as the turnaround resulting from a religious epiphany.

The difference between now and then, he says, is TM -- transcendental meditation, a method of deep relaxation through meditation that had its first burst of popularity in the U.S. in the 1960s and was a forerunner of such stress-control relaxation methods as the relaxation response, the quieting response and a host of techniques using biofeedback.

TM involves 20 minutes of meditation twice a day. In an ancient tradition, the meditator is assigned a "mantra," a word-sound that is silently repeated during meditation and serves as a focus for relaxation and a means to keep errant thoughts from interfering with the process.

According to advocates of stress management techniques, deep relaxation permits the conscious control of such normally automatic functions as heart rate, dilation of blood vessels, relaxation of smooth muscles.

Since the 1970s, the application of TM-like relaxation techniques to prison populations has been tested. Corum started his program in 1975. Generally, prison officials believe TM is one of a number of techniques used together or separately that can help minimize violence and wean inmates away from drugs.

Jasper Ormond, administrator of pilot drug projects for the D.C. Department of Corrections, says he believes that TM could have a place, along with other techniques, in drug rehabilitation programs. He is concerned that TM be a part of a comprehensive plan, not "just to come in solo as the cure-all." Currently, Ormond is running programs at the Lorton medium-security complex in suburban Virginia. About 25 women and 36 men take the classes, which combine meditation with counseling, therapy and other rehabilitation efforts.

A series of studies on TM, some published in respected, peer-reviewed science and social-science journals, suggest that this relaxation method can lead to a reduction of violence among inmates and a significant drop in the rate of people released from prison who are subsequently re-incarcerated.

In general, about 60 percent of former inmates will be back in jail within three years, studies have shown. Analyses of the studies on TM suggest that although it is clearly not the final answer to prisoner rehabilitation, it can cut the rate of repeated offenses by 40 percent.

A study of 259 California parolees who had learned TM techniques at San Quentin prison was published in 1987 in the Journal of Criminal Justice. The authors, Catherine R. Bleick and Allan I. Abrams of the Institute for Social Rehabilitation in Los Angeles, found that the recidivism rate among the meditators was 35 to 40 percent lower than among former convicts who had received prison education, vocational training or psychotherapy. They concluded that "these results indicate a reduction in recidivism due to TM practice that is of practical significance," with about 60 percent of parolees who learned TM still "clean" after two years but only 45 percent of non-TM parolees.

Charles Alexander, who teaches at TM's major educational institution -- Maharishi International University -- in Fairfield, Iowa, earned his PhD degree in psychology at Harvard by describing a TM program at Walpole state prison in Massachusetts. He followed the 53 inmates who learned TM and 251 controls for almost four years after they were paroled in the early 1980s. He found the same reduction in recidivism.

TM practitioners and teachers believe their technique is more effective than other relaxation strategies, such as biofeedback, which have also been tested on inmates, especially if its practice is maintained after the prisoner is freed. Up to now, they have been volunteering to lead programs in prisons at no cost. Nearly 3,000 prisoners have learned transcendental meditation in about 40 U.S. facilities, according to Alexander.

Corum makes no secret of his feeling that TM, in its way, provides him with the kind of "good feeling" he thought for two decades he could only get from drugs or alcohol, and his appearances on behalf of the movement reflect his zeal.

Some of the most impressive results on TM come from a study in Senegal. At a two-day seminar in the District this spring, some 300 area drug rehabilitation counselors and corrections officials heard TM instructors report that after transcendental meditation was taught to 11,000 people in 31 prisons in Senegal, their rate of return to prison in the following six months dropped from 90 percent to only 6 percent.

Meanwhile, the members of Corum's "group" are staying out of jail and continuing to meditate. One of them was a 350-pound gangland executioner, Corum said. Now he is living quietly, meditating daily. Another, who had been sentenced to life in prison without possibility of parole, is now a family man resettled in the San Francisco Bay area. The last one, a member of a Los Angeles street gang, is back on the streets, according to Corum, but now teaching TM as drug rehabilitation. "He's been where they're going," Corum said.