physical pain in patients with cancer; third, in increasing the perceived capacity to cope with significant problems and challenges; and fourth, in improving the reported overall quality of life. In addition, there is evidence supporting the brain and central nervous system's influence on the immune system and the capacity for mind-body interventions to enhance immune function outcomes, including defense against and recovery from infection and disease. Side effects are rarely reported in mind-body training. Some studies have indicated that meditation can have undesired adverse effects on specific clinical populations (e.g., people with a history of PTSD), although these are smaller studies. There is limited high-quality evidence as well with regard to the effect of intensity and duration. In a small study observing 87 healthy female participants undergoing either mind-body training or no training, participants who actively participated in an online program showed significantly greater resilience toward stress, anger, anxiety, and depression at 8 weeks than at 4 weeks into the study. However, this study was not randomized and the placebo effect may be large on the subjective psychological test scores. Recent meta-analyses of randomized controlled trials (RTCs) confirmed the efficacy of smartphone interventions for mental health problems, including depression, anxiety, and stress. Popularity Mind–body interventions are the most commonly used form of complementary and alternative medicine in the United States, with yoga and meditation being the most popular forms. See also Acupuncture Alexander technique Art therapy Breathing exercises Chiropractic Dance therapy Feldenkrais Method Guided imagery Guided meditation Hypnosis Hypnotherapy Massage therapy Meditation Mindfulness-Oriented Recovery Enhancement Music therapy Osteopathic manipulation Pilates Prayer Progressive muscle relaxation Qigong Rolfing Tai chi Trager approach Yoga References Alternative medicine Health promotion