“…Longitudinal studies seeking to relate childhood sleep problems to problems later in childhood, adolescence, or adulthood are uncommon, and have generally not found numerous or consistent predictive relationships. In the short term, however, ISD is associated with other difficulties (e.g., Klackenberg, 1982;Richman, 1981;Zuckerman, Stevenson, & Bailey, 1987). Children do not necessarily "grow out" of ISD (Zuckerman et al, 1987), and the development of secondary ISD is quite common, affecting be-tween 19% to 50% of families (Fergusson et al, 1981;Moore & Ucko, 1957).…”