There is solid evidence that mindfulness therapy, which combines elements of Buddhism and yoga, can relieve anxiety and improve mood.

Of all fields of medicine, psychology seems especially prone to fads. Freudian dream analysis, recovered memory therapy, eye movement desensitization for trauma — lots of once-hot psychological theories and treatments eventually fizzled.

Now along comes mindfulness therapy, a meditation-based treatment with foundations in Buddhism and yoga that’s taking off in private practices and university psychology departments across the country.

“Mindfulness has become a buzzword, especially with younger therapists,” said Stefan Hofmann, a professor of psychology at Boston University’s Center for Anxiety and Related Disorders.

Mindfulness therapy encourages patients to focus on their breathing and their …