Why Bipolar Kids Can’t Get Up and Get Going
The Typical Architecture Of Sleep
Normally throughout the night a person experiences two kinds of sleep that alternate rhythmically. One is called rapid eye movement (REM) sleep, during which most dreaming takes place; the other (not surprisingly) is called non-REM.
Non-REM sleep has a four-stage development plan as revealed by electroencephalogram (EEG) sleep studies. Sleep typically begins the night with a light stage 1 sleep where the brain waves are small and fast. After approximately 30 minutes, the sleeper slips deeper into sleep as Stages 2, 3, and 4 of non-REM sleep progress. EEGs of Stage 3 reveal larger and slower brain waves. Stage 4 brain waves are large, slow, and regular and this is the deepest period of sleep.
After approximately 90 minutes, a brief period of REM sleep appears. This is the dreaming state and the eyeballs can be observed moving rapidly beneath the eyelids. A 90-minute oscillating pattern develops with REM sleep asserting itself for longer periods of time. The first 90-minute cycle might consist of 85 minutes of non-REM sleep and 5 minutes of REM, but by the time the fourth cycle rolls around, it might consist of 60 minutes of non-REM and 30 minutes of REM.
But all is not so regular. As Drs. Mark W. Mahowald and Carlos H. Schenck of the Minnesota Regional Sleep Disorders Center at the University of Minnesota Medical School have written:
The rapid oscillation of states or the inappropriate intrusion of elements of one state into another may result in the appearance of parasomnias (night terrors, restless leg syndrome, teeth grinding, sleep walking, and confused arousals). Given the large number of neural networks, neurotransmitters, and other state-determining substances that must be recruited synchronously, and given the frequent transition among the three states of being, it is surprising that parasomnias do not occur more often.
A significant number of children with bipolar disorder do seem to be suffering several of these parasomnias, especially night terrors and confused arousals.
It may be that children and adolescents are being asked to get up and go to school when they are in the deepest, slow-wave pattern of sleep. Sleep research has shown that abrupt awakenings during a slow wave sleep episode produce more sleep inertia than awakening in stage 1 or 2 when the brain waves are small and fast. Awakenings during a REM episode produces some sleep inertia, but not as much as awakenings during slow-wave sleep.
Research is also revealing that sleep inertia is more intense when awakening occurs near the trough—the low point—of the core body temperature as compared to its peak. Sleep/wake irregularities, as well as irregularities of the thermoregulatory system, contribute to sleep inertia.