Time in prison is hard time. It's supposed to be. Yet because most prisoners will eventually rejoin society, teaching them to control their emotions is a good idea.

Transcendental Meditation (TM) made prison substantially less traumatic for prisoners; it changed their personality in ways that should help them productively re-enter society.

“I have watched inmates learn Transcendental Meditation and become more human after a long and isolating period of becoming less human,” said Tom O'Connor, the co-author of the largest randomized controlled trial to date of prisoners and TM.

Prisoners' lives are often not happy. They have one of the highest rates of lifetime trauma of any segment of society, with recent surveys showing that 85% have been a victim of a crime, such as robbery or home invasion, or physical or sexual abuse. Not only does this negatively impact their health, it also makes them more likely to return to prison once released.

A shift from an overly aroused state to a more stable one may help explain how TM lowers trauma symptoms.

The study looked at whether four months of practicing TM might help prisoners get over some of the traumatic events that helped propel them to prison in the first place.

TM uses a mantra, a word or phrase that is repeated mentally, to create a state of restful alertness that is simple enough that even children with ADHD can learn it. For the study, over 180 moderate-to high-risk inmates at two Oregon prisons were randomly assigned to either the TM group or a non-meditating control group.

After being taught TM in five one-hour sessions, the TM group was then encouraged to practice it for 20 minutes twice a day, once in the morning and once in the late afternoon. Eighty percent of the men reported practicing it at least once a day, with 68% practicing twice a day on average.

Smaller studies of TM in several prisons, including Folsom State Prison, San Quentin State Prison in California and Walpole State Prison in Massachusetts, have found that the rates of return to prison are even lower — reduced rates of recidivism (return to prison), range from 33% to 47%.

That's because TM decreases the hyperarousal of the sympathetic nervous system, the hypothalamus, the pituitary and the adrenal glands, all of which are involved in the fight or flight response. A shift from an overly aroused state to a healthier, more stable one may help explain how TM lowers trauma symptoms.

Of course, you don't need to be in jail to try TM. Most people could use a little less trauma in their life.

The study appears in the Permanente Journal.