"Researchers have known for 30 years that meditating can have adverse health effects on some people, inducing psychological and physical problems ranging from muscle spasms to hallucinations. But around the Bay Area, eyes seem closed to the data. "A lot of people do experience negative side effects," says Dr. Maggie Phillips, the director of the California Institute of Clinical Hypnosis and a licensed psychologist in Oakland..."

"The harmful effects aren't limited to one specific technique or even long retreats." "Those effects can include facial tics, insomnia, spacing out, and even psychotic breakdowns. Dr. Margaret Singer, clinical psychologist emeritus at Berkeley, with research partner Dr. Janja Lalich, collected case histories from 70 clients seeking treatment for problems that began during meditation practice. Their research presents several examples of these symptoms and notes that prior to meditating, none of the patients had individual or family histories of mental disorders."

"Dr. Michael Persinger, a psychologist at Laurentian University in Canada, found in 1993 that meditation induces epilepsylike brain seizures in some people. His study of 1,081 students showed that the 221 meditators among them had a higher rate of hallucinating floating spots of light, hearing voices, and even feeling the floor shake. Other studies reported that meditators complained of feeling emotionally dead and seeing the environment as unreal, two-dimensional, amorphous."