Hallucinations and aberrant perceptions are prevalent among the young healthy adult population

Hallucinations are frequent in clinical practice, with an incidence of up to 38.7% in the general population. We aim to determine the prevalence of hallucinations among healthy young adults in our environment.

We designed an observational study, using as subjects 3rd to 6th year medical students at the Universidad Complutense de Madrid who complete clinical rotations in the Hospital Clínico San Carlos. After a screening questionnaire, an individual interview was conducted via telephone or e-mail to those students who reported hallucinations. We obtained clinical and epidemiological data through a semi-structured clinical interview performed by a third year neurology resident.

N=134 (average age was 22.1 years; 77.6% were women). 74 respondents answered affirmatively to one or more screening questions, and 54 completed the follow-up interview. 22.2% described visual phenomena and 64.8%, auditory. The majority reported sleep-related experiences and auditory perceptions related to hyper vigilance, such as hearing the telephone or the doorbell ring when in fact it had not (38.8%). All subjects had good insight into their experiences and none had psychotic symptoms. Two cases were associated with substance abuse.

Hallucinations are frequent among the general population. Traditionally, auditory phenomena have been associated with psychotic pathology, and other studies show a low population incidence (0.6%). However, in our sample, short auditory perceptions with immediate analysis were frequent and not pathological.