A new study has found that perceptual disturbances — a milder form of full-blown hallucinations — are not necessarily predictive symptoms of schizophrenia. Perceptual disturbances may involve seeing shadows or hearing knocking noises with a sense that these experiences are “not real.”
Although some people with perceptual disturbances do go on to develop full-blown psychosis, there are just as many people with these symptoms who do not, according to the researchers.
Instead, they found that suspiciousness and unusual thought content are most likely to signal the onset of the disease. This risk is further enhanced if the person shows difficulty with focus or concentration.