TWIN STUDY ON NIGHT TERRORS, FEARS AND SOME PHYSIOLOGICAL AND BEHAVIORAL-CHARACTERISTICS IN CHILDHOOD

Ninety-three pairs of same-sex twins were examined at the age of 3 years and their mothers were interviewed to assess the twins' behaviours. Sixty-one pairs were followed up. The monozygotic twins were found to be significantly more concordant than the dizygotic with respect to reaction to sudden noises and absence of stranger anxiety in the first year of life, and in ability to sleep alone and clinging to the mother at 3 years. A significant difference in concordance was also found for abundant salivary drooling in infancy, motion sickness, constipation, perspiration and bedwetting at 3 years, and night terrors at 3 years or at follow-up.