According to a new study, meditation and mindfulness, which are widely perceived as stress-reduction techniques, can also have adverse effects like anxiety, depression, and much less frequently, even suicidal behaviors.

Published this month in Acta Psychiatrica Scandinavica, the study concluded that the overall prevalence of adverse events of meditation was 8.3 percent. Having performed a meta-analysis of 83 studies published between 1975 and 2019, with a total of 6,703 participants, the researchers found that 55 of these 83 studies included reports of at least one type meditation-related adverse effect. The most common adverse effects of meditation the researchers found were: anxiety, reported in 33 percent of the studies, depression in 27 percent, and cognitive anomalies in 25 percent. Gastrointestinal problems, and suicidal behaviors, were both found in 11 percent of the studies reviewed by the authors, and were the least frequent among the adverse effects.

“For most people [meditation] works fine but it has undoubtedly been overhyped and it’s not universally benevolent… People have experienced anything from an increase in anxiety up to panic attacks,” Dr. Miguel Farias, who leads the Brain, Belief and Behaviour research group at Coventry University in the UK, and lead author of the study, told New Scientist. He also added that the figure of 8.3 percent could be an underestimate because a lot of studies either record only serious negative effects, or don’t record adverse effects at all.

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The researchers noted that they could not ascertain whether individuals with a mental health history were more vulnerable to experiencing these adverse effects. But, in the course of the meta-analysis, they did find that people with no history of mental health disorders had experienced adverse effects of meditation — either during, or following, their meditation practice. But, Katie Sparks, a chartered psychologist and a member of the British Psychological Society, who was not involved in the study, expressed concerns that the adverse effects could be attributed to people trying out meditation because of undiagnosed anxiety or depression. But, she added that sometimes, when people attempt to “still their thoughts,” the mind can “rebel” — “It’s like a backlash to the attempt to control the mind, and this results in an episode of anxiety or depression,” she said. However, she also opined that instead of being completely discouraged to try meditation, people can opt for guided meditation sessions.

A 2019 study of 1,232 people had found that over 25 percent of the participants reported experiencing “particularly unpleasant” emotions like “anxiety, fear, distorted emotions or thoughts,” which they believed “may have been caused by their meditation practice.” And even though existing research suggests that mindfulness-based cognitive therapy can help with sleep disorders, reducing stress-symptoms, and even curtailing addiction, experts worry about the lack of rigorous evidence on the subject, alongside inconsistent definitions of mindfulness.

The study cites a 1977 recommendation by the American Psychiatric Association, which had stated that: “research [must] be undertaken in the form of well‐controlled studies to evaluate the possible specific usefulness, indication, contraindications, and dangers of meditative techniques.” But now, in 2020, the researchers note how it has taken decades to even acknowledge that there “might be a bias towards exaggerating the clinical benefits of meditation practice and dismissing its potential adverse effects.”