"There is an enormous amount of interest in using meditation as a form of therapy to cope with a variety of modern-day health problems, especially hypertension, stress and chronic pain, but the majority of evidence that seems to support this notion is anecdotal, or it comes from poor quality studies," say Maria Ospina and Kenneth Bond, researchers at the University of Alberta/Capital Health Evidence-based Practice Center in Edmonton, Canada.
In compiling their report, Ospina, Bond and their fellow researchers analyzed a mountain of medical and psychological literature--813 studies in all--looking at the impact of meditation on conditions such as hypertension, cardiovascular diseases and substance abuse.
They found some evidence that certain types of meditation reduce blood pressure and stress in clinical populations. Among healthy individuals, practices such as Yoga seemed to increase verbal creativity and reduce heart rate, blood pressure and cholesterol. However, Ospina says no firm conclusions on the effects of meditation practices in health care can be drawn based on the available evidence because the existing scientific research is characterized by poor methodological quality and does not appear to have a common theoretical perspective.
"Future research on meditation practices must be more rigorous in the design and execution of studies and in the analysis and reporting of results," Ospina explains.
But the researchers caution against dismissing the therapeutic value of meditation outright. "This report's conclusions shouldn't be taken as a sign that meditation doesn't work," Bond says. "Many uncertainties surround the practice of meditation. For medical practitioners who are seeking to make evidence-based decisions regarding the therapeutic value of meditation, the report shows that the evidence is inconclusive regarding its effectiveness." For the general public, adds Ospina, "this research highlights that choosing to practice a particular meditation technique continues to rely solely on individual experiences and personal preferences, until more conclusive scientific evidence is produced."
The report, published June 2007 and titled Meditation Practices for Health: State of the Research, identified five broad categories of meditation practices: mantra meditation, mindfulness meditation, Yoga, Tai Chi and Qi Gong. Transcendental Meditation and relaxation response (both of which are forms of mantra meditation) were the most commonly studied types of meditation. Studies involving Yoga and mindfulness meditation were also common.
The research was conducted by the University of Alberta Evidence-based Practice Center under contract to the U.S. Department of Health and Human Services' Agency for Healthcare Research and Quality. It was requested and funded by the National Center for Complementary and Alternative Medicine in Bethesda, Md.