Insomnia and Mood Disorders
Insomnia is defined as repeated difficulty with sleep initiation, maintenance or quality that occurs despite adequate time and opportunity for sleep and results in some sort of daytime impairment. Specific criteria vary, but common ones include taking longer than 30 minutes to fall asleep, staying asleep for less than six hours, waking more than three times a night, or experiencing sleep that is chronically nonrestorative or poor in quality.
Chronic insomnia, lasting more than one month, can be associated with impaired occupational and social performance, high absenteeism and higher healthcare use. It can also be a risk factor for depression, anxiety, alcohol addiction, substance abuse and suicide.
According to the American Academy of Sleep Medicine, approximately 30 percent of adults have symptoms of insomnia. Additionally, the National Sleep Foundation estimates that nearly 70 percent of individuals with insomnia experience symptoms for one year, and half still have insomnia for as long as three years.
There are two main processes that regulate sleep and wakefulness: the circadian system, related to the 24 hour clock, and the homeostatic system, related to how long a person has been awake before going to sleep. Both systems involve a complex interplay between neurons that produce wakefulness-inducing neurotransmitters and sleep-promoting neurotransmitters. Light hitting the retina activates neurons, which initiates a chain of signals culminating in the activation of orexin producing neurons (involved in maintaining wakefulness), as well as the inhibition of the sleep-promoting hormone melatonin.
Learn more about why we are developing Seltorexant (MIN-202) to treat insomnia and mood disorders.