“Patients who had higher levels of belief in God demonstrated more effects of treatment,” said the study’s lead author, David H. Rosmarin, a psychologist at McLean Hospital and director of the Center for Anxiety in New York. “They seemed to get more bang for their buck, so to speak.”

One possible reason for this, he said, is that “patients who had more faith in God also had more faith in treatment. They were more likely to believe that the treatment would help them, and they were more likely to see it as credible and real.”

Of the 56 people who expressed the strongest belief in God, 27 also had very high expectations for the treatment, while nine had very low expectations. In contrast, of the 30 patients who said they had no belief in God or a higher power, only two had high expectations for the treatment.

“It’s one of the first studies I’ve read that actually looks at perhaps a mechanism” for “why we see some correlation between the strength of religious commitment or the strength of spiritual commitment and better outcomes,” said Dr. Marilyn Baetz, a psychiatrist at the University of Saskatchewan who studies the effects of religion and spirituality on mental health.