Hands off and on in schizophrenia
Appendage illusion points to disturbed body sense in psychotic ailment
By Bruce Bower
People with schizophrenia rapidly and intensely perceive phony replicas of hands as their own, possibly contributing to this mental ailment’s signature hallucinations, a new study suggests.
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In a series of tests, people with schizophrenia believed a rubber hand placed in front of them was theirs if the visible fake hand and the patient’s hidden, corresponding hand were simultaneously stroked with a paintbrush.
Mentally healthy people took longer to experience a less dramatic version of this rubber-hand illusion than schizophrenia patients did, but the effect’s vividness increased among healthy volunteers who reported magical beliefs, severe social anxiety and other characteristics linked to a tendency to psychosis, psychologist Sohee Park of Vanderbilt University in Nashville and her colleagues report online October 31 in PLoS ONE.