Dream-enacting behaviors in a normal population

Abstract

Study objectives: Determine the prevalence and gender distributions of behaviors enacted during dreaming ("dream-enacting [DE] behaviors") in a normal population; the independence of such behaviors from other parasomnias; and the influence of different question wordings, socially desirable responding and personality on prevalence.

Design: 3-group questionnaire study.

Setting: University classrooms

Participants: Three undergraduate samples (Ns = 443, 201, 496; mean ages = 19.9 +/- 3.2 y; 20.1 +/- 3.4 y; 19.1 +/- 1.6 y).

Interventions: N/A.

Measurements and results: Subjects completed questionnaires about DE behaviors and Social Desirability. Study 1 employed a nonspecific question about the behaviors, Study 2 employed the same question with examples, and Study 3 employed 7 questions describing specific behavior subtypes (speaking, crying, smiling/laughing, fear, anger, movement, sexual arousal). Somnambulism, somniloquy, nightmares, dream recall, alexithymia, and absorption were also assessed. Factor analyses were conducted to determine relationships among DE behaviors and their independence from other parasomnias. Prevalence increased with increasing question specificity (35.9%, 76.7%, and 98.2% for the 3 samples). No gender difference obtained for the nonspecific question, but robust differences occurred for more specific questions. Females reported more speaking, crying, fear and smiling/laughing than did males; males reported more sexual arousal. When controlling other parasomnias and dream recall frequency, these differences persisted. Factor solutions revealed that DE behaviors were independent of other parasomnias and of dream recall frequency, except for an association between dream-talking and somniloquy. Sexual arousal was related only to age. Behaviors were independent of alexithymia but moderately related to absorption.

Conclusions: Dream-enacting behaviors are prevalent in healthy subjects and sensitive to question wording but not social desirability. Subtypes are related, differ with gender and occur independently of other parasomnias.

Figure 1

Subjects responding > 0 (out of 7) to items about dream-enacting behaviors, somnambulism, and somniloquy in reaction to either a nonspecific question or a question that includes examples. The question with examples dramatically increased prevalence estimates for dream-enacting behaviors but not estimates of somnambulism or somniloquy. Last-year = estimate for previous year; Childhood = estimate for childhood (ages 4-16)

Figure 2

Prevalence of 7 subtypes of dream-enacting behavior, i.e., % subjects reporting speaking, motor activity, 4 types of emotions and sexual arousal at least rarely in the last year. Somnambulism and somniloquy estimates are presented at right for comparison.

Figure 3

Gender differences in percent of subjects reporting dream speaking, motor activity, emotions and sexual arousal “sometimes” or “often.” Females more frequently reported behaviors on all items except sexual arousal, which was characteristic of males (unpaired t tests for gender: ‡P < 0.06; **P < 0.005; ***P < 0.000001; ****P < 0.0000001). Somnambulism and somniloquy did not differentiate the sexes.