Every child, every person, is regulated by an internal clock, called circadian rhythm. It was thought that there was a “master clock” in the brain, coordinating the 24-hour cycle of light and darkness. It is more complicated as every organ and cell keeps time. Working together, all these “clocks” not only regulate sleep but our metabolism, hormones, body temperature, cognition, mood, and many other small but important processes of life.
We live in a difficult time for these clocks with glowing screens, shift work, 24-hour light pollution and erratic schedules. Concern about our clocks is obvious with Apple watches, Fitbits and Oura rings. As we learn more about circadian biology researchers are finding that poorly functioning clocks are associated with tumor growth and some mental illnesses. Some feel that poorly functioning clocks may be associated with depression, anxiety, bipolar disorder, schizophrenia and ADHD. Those studying longevity are finding keeping the body’s clocks in order might affect how we age.
Other studies in people with ADHD show that the body’s internal clocks may be altered. Cortisol, a hormone involved in alertness, energy use and stress response, can be delayed and blunted when compared to people without ADHD. Brain MRI’s have found that the pineal gland (makes melatonin) in their brains is smaller.
Studies have shown the sleep/circadian disruptions are very common in ADHD. One recent study estimated that 73-78 percent of children and adults with ADHD have delayed sleep-wake times. The time of melatonin release occurs later in people with ADHD. Insomnia and other sleep disturbances have been reported in up to 80 percent of adults with ADHD.
The differences in the timing of the internal clocks are known as a chronotype which is partly influenced by genetics. There are at least 10 known genes associated with sleep conditions such as familial short sleep, familial advanced sleep phase, and delayed sleep phase. These phases can change over a lifetime. Children’s chronotypes tend to be relatively early, then shift to later in adolescence before moving back.
One of the types of sleep disorders known as Delayed Sleep Phase Syndrome which is when the sleep schedule does not fit with society’s schedule. These individuals cannot go to sleep until very late (3 AM) and, if allowed, would sleep until 11 AM. Hard to go to school.
Additional sleep problems can be a side effect of stimulant medications used to treat ADHD. Others, such as guanfacine and clonidine, may cause drowsiness. Melatonin is used as a sleep aid, but it is not a sleeping pill. The American Academy of Pediatrics advises parents to work with their pediatrician and to start melatonin with the lowest possible dose. The pediatrician can help with the proper dose, timing and monitoring of melatonin.
Poor sleep makes the symptoms of focus, emotional regulation, working memory and impulse control worse. Unmanaged ADHD symptoms make it harder to wind down and create a cycle of behavior.
Good resources can be found in the Sleep Foundation or the Attention Deficit Disorder Association.
by Sally Robinson, MD Clinical Professor
Keeping Kids Healthy
Published 10/26