In a review of recent research, international experts say there is increasing evidence that fake treatments, or placebos, have an actual biological effect in your body.

The doctor-patient relationship, plus the expectation of recovery, may sometimes be enough to change a patient's brain, body and behavior, experts write. While doctors have long recognized that placebos can help patients feel better, they weren't sure if the treatments sparked any physical changes.

In a review, researchers cite studies where patients with Parkinson's disease were given dummy pills. That led their brains to release dopamine, a feel-good chemical, and also resulted in other changes in brain activity.