VISUAL HALLUCINATIONS IN PSYCHOLOGICALLY NORMAL PEOPLE - CHARLES-BONNETS-SYNDROME

Background Bonnet's Syndrome (CBS) characterised by the presence of co mplex visual hallucinations in psychologically normal people, was cons idered for a long time to be rare. Systematic research on CBS has been limited. However, it has been realised that CBS occurs frequently in elderly, visually handicapped patients, and we have been able to study the syndrome in a large number of patients. Methods After screening 5 05 visually handicapped patients, 60 were found to meet proposed diagn ostic criteria for CBS (generally, the existence of hallucinations wit hout delusions or loss of insightful cognition.) Psychopathological ch aracteristics, personal meaning, and the emotional impact of hallucina tions, as well as factors influencing the hallucinations, were analyse d. Findings Although diagnostic criteria demand merely ''partial insig ht'', all patients had full insight into the unreal nature of their ha llucinations. Other characteristics varied. In 46 (77%) patients, hall ucinations lacked a personal meaning. Sensory deprivation and a low le vel of arousal seemed to favour the occurrence of hallucinations. CBS caused considerable distress in only 17 (28%) patients. However, all p atients were glad to be told that their hallucinations were not due to mental disease. The proper diagnosis had been made in only one of the 16 patients who had consulted a doctor. Interpretation Although large ly unrecognised in clinical practice, CBS should be considered as a di agnosis in patients who complain of hallucinations and who meet define d diagnostic criteria. There is no proven treatment, but many patients will benefit from reassurance that their hallucinations do not imply mental illness.