[Sleeping behavior between the ages of 2 and 18. Longitudinal study].

Sleeping behavior was investigated in 320 Swiss children 2 to 18 years of age. The data were based on the First Zurich Longitudinal Study (1954-1980). The incidence of resistant behaviour at bedtime increased from 8 to 40% between age 2 and 10. Evening wakefulness was observed in 20% of the 2- to 7-year-old children, and in 40-50% of the older children. The incidence of night waking decreased from 40-50% in the preschool period to 20% at age 12.20% of the 2 to 4-year-old children and only 1% of the 12-year-old children woke up every night. Evening wakefulness and night waking were observed in some children over periods of several years. Up to age 5 the incidence of "bad dreaming" was 60%, subsequently it decreased to about 25%. Somnambulism was observed in 5% of the children. None of the described sleeping behaviors showed sex differences.