the presence of a parent) or from the absence of consistent sleep schedules and bedtime
routines. Insomnia in adolescenc e is often triggered or exacer bated by irregular sleep sched-
ules (e.g., phase delay). In both children an d adolescents, psycholo gical and medical fac-
tors can contribute to insomnia.
The increased prevalence of insomnia in olde r adults is partly explained by the higher