RM had his first out-of-body experience at the age of 16. Now, at the age of 55, he has had more than he can count. They usually happen just before he falls asleep; for ten minutes, he feels like he is floating above his body, looking down on himself. If the same thing happens when he’s awake, it’s a far less tranquil story. The sense of displacement is stronger – his real body feels like a marionette, while he feels like a puppeteer. His feelings of elevation soon change into religious delusions, in which he imagines himself talking to angels and demons. Psychotic episodes follow. After four or five days, RM is hospitalised. This has happened between 15 to 20 times, ever since RM was first diagnosed with schizophrenia at the age of 23. He hears voices, and he suffers from hallucinations and delusions. Despite these problems, he managed to hold down a job as a reporter until 2002 and more recently, he has been working in restaurants and volunteering as an archivist. Then, about a year ago, he took part in a study that seems to have changed his life. For around a decade, RM has taken part in several studies designed by Sohee Park, a neuroscientist from Vanderbilt University who works on schizophrenia. “He’s a very interesting guy,” says Park. “He has very deep insight into his condition.” Park’s student Katharine Thakkar was testing the idea that people experience psychotic experiences because they have a weak sense of self. It’s an idea that others have suggested before but it seems like something that would be hard to test with experiments. But not so: over the last decade, psychologists have shown that our sense of self is far from the fixed, permanent feeling that we assume it is. Instead, it is disarmingly pliable. You can tweak it. You can study it. Our brain continuously constructs our sense of self using information from our eyes, skin and joints. By tweaking that information using simple illusions, scientists have warped and displaced our sense of self in the lab. The most famous of these – the rubber-hand illusion – debuted as a party trick at a Halloween bash. Princeton scientists stroked a rubber hand in time with someone’s real hand, which was hidden out of sight. A few seconds later, the volunteer genuinely felt that they owned the rubber hand. Since then, scientists like Henrik Ehrsson have taken the illusion to new extremes, convincing people that they have gained a third arm, jumped into a mannequin or left their own bodies. But the rubber hand illusion is still proving useful. Thakkar performed the trick on 24 people with schizophrenia, including RM, and asked them to describe their experiences on a questionnaire. Their answers revealed that they experienced the illusion more strongly that 21 people of a similar age and background, but who didn’t have schizophrenia. Not taking their word for it, Thakkar tested for other signs that people had bought into the illusion: a feeling that their fingers had moved, and a drop in the temperature of their real hand. She found both, and to a stronger extent in people with schizophrenia than in those without. The results suggest that schizophrenia is accompanied by a weaker or more flexible sense of body ownership than usual. Indeed, Thakkar found that people who experienced the most severe hallucinations (and some delusions) also felt the rubber-hand illusion most strongly. But even among the group with schizophrenia, RM stuck out. The synchronous stroking didn’t just convince him that he had a rubber hand – it brought about one of his full-on out-of-body experiences. He felt that he and Thakkar were both levitating a foot off the floor: back to the ceiling, turning in a circle, and watching themselves on their chairs. The effect lasted for a few minutes, before they landed again. Others have duplicated this effect in the lab, but with more complicated set-ups involving cameras and virtual reality headsets. The rubber hand illusion shouldn’t do anything quite that dramatic. RM was worried that a psychotic episode was on the horizon, but Park’s team had no idea about his history and he didn’t mention it. “We were so excited when it happened the first time, and he’s very helpful,” says Park. When they asked him to come back and repeat the experiment, he agreed. He wanted to know more too. When he returned, Thakkar duplicated the same experience and this time, RM actually found the experience to be quite pleasant and wanted the feeling to come back. That was when he told the scientists about his history. “We got really worried, because we’d just induced these twice!” recalls Park. But she didn’t need to worry. After the experiment, RM wanted to know more, so Thakkar plied him with information and journal articles about out-of-body experiences. He learned that the phenomenon had a name. He learned that scientists could willingly duplicate the effect in a lab. He learned that they had identified parts of the brain that are associated with the experiences. The information was revelatory. “He gained a psychological cause for this apparently supernatural phenomenon,” says Park, “and he has used this knowledge to control his symptoms.” Since then, RM hasn’t had a psychotic episode. This approach almost certainly won’t work for everyone – bear in mind that RM is high-functioning and self-aware. He is very eloquent and has an IQ of 120. Park notes that similar explanations might also help other people with unusual experiences like out-of-body effects, since these could exacerbate the other symptoms of schizophrenia. “If it feels supernatural, that just feeds into the delusions,” she says. The study has broader implications for helping people with schizophrenia. Activities that promote a stronger sense of body awareness, such as yoga, dance or playing a musical instrument, might help to alleviate some of the symptoms of schizophrenia. But for RM, it seems that learning more about his condition was enough. A year on, his diagnosis is unchanged, he still gets out-of-body experiences, and he still hears voices. But gone are the days when his experiences would require a stay in a hospital. He is now hoping to establish himself as a freelance writer, and he’s even had a paper on religion accepted in a peer-reviewed academic journal. For him, knowledge has proven to be a potent treatment. “We check up with him regularly and he’s been doing really well,“ says Park. Reference: Thakkar, Nichols, McIntosh & Park. 2011. Disturbances in body ownership in schizophrenia: evidence from the rubber hand illusion and case study of a spontaneous out-of-body experience.