Nightmare frequency as a function of age, gender, and September 11, 2001: Findings from an Internet questionnaire.

Retrospective estimates of nightmare frequency for a sample of 23,990 re-spondents to an Internet questionnaire (female: N 19,367, mean age 24.9 10.14 years; male: N 4,623; mean age 25.5 10.81) were evaluated as a function of age, gender, and pre- versus post-September 11, 2001. Female respondents reported more frequent monthly nightmares (4.44 6.71) than did male respondents (3.39 6.07), and this result was seen for all age strata younger than 60. Also, for female respondents, night-mare frequency increased from ages 10–19 to 20–39 then decreased mono-tonically to ages 50–59. For male respondents, nightmare frequency was stable from ages 10–19 to 30–39 then decreased to ages 50–59. An increase in nightmare frequency was observed post-September 11 only for male respondents—particularly for 10- to 29-year-olds. This increase was sus-tained 2 years later. These effects were maintained when dream recall was held constant. Results replicate, in a single sample, previously published gender and age effects and provide new evidence that the nightmares of males may be differentially sensitive to traumatic events for which victims and/or perpetrators are primarily male.