At Beth Israel Deaconess Medical Center in Boston, doctor's orders can include an unlikely prescription: meditation.

"I recommend five minutes, twice a day, and then gradually increase," said Aditi Nerurkar, a primary-care doctor and assistant medical director of the Cheng & Tsui Center for Integrative Care, which offers alternative medical treatment at the Harvard Medical School-affiliated hospital. "It's basically the same way I prescribe medicine. I don't start you on a high dose right away." She...