Sleep disturbance may take the form of either difficulty sleepin g or sleeping exces-
sively (Criterion A4). When insomnia is presen t, it typically takes the form of middle in-
somnia (i.e., waking up during the night an d then having difficulty returning to sleep) or
terminal insomnia (i.e., waking too early and be ing unable to return to sleep). Initial in-
somnia (i.e., difficulty falling asleep) may al so occur. Individuals who present with over-
sleeping (hypersomn ia) may experience prolonged sleep episodes at night or increased
daytime sleep. Sometimes the reason that the individual seeks trea tment is for the dis-
turbed sleep.