A study carried out by the Royal College of Surgeons in Ireland Research Lecturer in Neurological and Psychiatric Disorders, Dr Ian Kelleher, has revealed that more than 4 per cent of the adult population have experienced auditory and/or visual hallucinations. The paper, published in the current issue of The British Journal of Psychiatry, explains that research has shown that hallucinations occur much more commonly outside of a diagnosis of schizophrenia, across a whole range of mental illnesses and even in people with no mental illness.
Lead author on the paper, Dr Ian Kelleher, from the RCSI Department of Psychiatry, said: “Auditory and visual hallucinations are typically considered to be symptoms of psychosis/schizophrenia, however the main findings from this paper show that hallucinations are much more common than people realise. Hallucinations can occur in any mental illness and can also occur in people who do not have any mental illness.” Overall, 4.4 per cent of adults in the general population experienced hallucinations. Looking more specifically at the relationship between hallucinations and mental illness, the research found that hallucinations were quite common across all mental disorders and not just schizophrenia, as is usually thought.
For example, 14 per cent of people with depression had hallucinations, 17 per cent of people with obsessive compulsive disorder had hallucinations and nearly a quarter of people with agoraphobia had hallucinations. This research paper was based on a detailed review of research data from England which was carried out on a large general adult population sample. The co-author on the publication is Dr Jordan De Vylder from the University of Maryland, USA.