AIMS: The aim of the present study was to evaluate the prevalence and characteristics of sleep paralysis in adolescents using a folk expression. METHODS: Three hundred and twenty-two adolescents (mean age, 15.9 +/- 0.88 years; 66.8% female) from three high schools in Mexico City completed both a self-reported questionnaire, including a colloquial definition of sleep paralysis and the Epworth Sleepiness Scale. RESULTS: A high proportion of the adolescents (92.5%) had heard about the 'a dead body climbed on top of me' expression and 27.6% of them had experienced the phenomenon. Sleep paralysis was present in 25.5% while the prevalence rate for hypnagogic/hypnopompic hallucinations was 22%; 61% had experienced >or=2 episodes in their lifetime. The mean age of onset was 12.5 +/- 3 years. Sleepiness scores for the subjects who had experienced at least one event were not significantly different from subjects who had not experienced any. In 72% of cases, the episodes were composed of both sleep paralysis and hallucinations while 20.2% consisted of only sleep paralysis and 7.8% of only hallucinations. The number and characteristics of events were not significantly different between adolescents with only one episode and those with two or more episodes. CONCLUSIONS: The characteristics of the 'a dead body climbed on top of me' phenomenon suggest that is identical to sleep paralysis and a frequent experience among Mexican adolescents. During adolescence, sleep paralysis seems to be a recurrent phenomenon frequently accompanied by hallucinatory experiences.
AIMS: The aim of the present study was to evaluate the prevalence and characteristics of sleep paralysis in adolescents using a folk expression. METHODS: Three hundred and twenty-two adolescents (mean age, 15.9 +/- 0.88 years; 66.8% female) from three high schools in Mexico City completed both a self-reported questionnaire, including a colloquial definition of sleep paralysis and the Epworth Sleepiness Scale. RESULTS: A high proportion of the adolescents (92.5%) had heard about the 'a dead body climbed on top of me' expression and 27.6% of them had experienced the phenomenon. Sleep paralysis was present in 25.5% while the prevalence rate for hypnagogic/hypnopompic hallucinations was 22%; 61% had experienced >or=2 episodes in their lifetime. The mean age of onset was 12.5 +/- 3 years. Sleepiness scores for the subjects who had experienced at least one event were not significantly different from subjects who had not experienced any. In 72% of cases, the episodes were composed of both sleep paralysis and hallucinations while 20.2% consisted of only sleep paralysis and 7.8% of only hallucinations. The number and characteristics of events were not significantly different between adolescents with only one episode and those with two or more episodes. CONCLUSIONS: The characteristics of the 'a dead body climbed on top of me' phenomenon suggest that is identical to sleep paralysis and a frequent experience among Mexican adolescents. During adolescence, sleep paralysis seems to be a recurrent phenomenon frequently accompanied by hallucinatory experiences.