Health professionals carefully distinguish between primary and secondary insomnia. Primary insomnia is the label used when the main reason for not falling asleep is directly related to the biological processes that induce the sleep cycle. By contrast, a patient is diagnosed with secondary insomnia when an unrelated medical condition is determined to be causing the inability to fall asleep.

Orexin neurons determine quality of sleep
Photo by Institute for Stem Cell Research via Getty Images
One of the organs involved is the hippocampus, which is located in the medial temporal lobe. Research has found that patients who are sleep deprived for extended periods of time will have a reduction in size and volume of the aforementioned organ in both hemispheres of the brain. This aptly explains the measurable loss of memory function for which the hippocampus is mostly known.

Primary insomnia has been linked to dysregulation of pain sensation in the body. One study has found that patients with primary insomnia are likely to report episodes of pain more frequently than other individuals. Patients who have chronic primary insomnia (3+ nights a week for one month or more) will also have ongoing pain. For this reason, the processes that inhibit pain are also consistently activated.

This may appear to be a good response, however it is not. The constant activation undermines the benefits of pain facilitation and inhibition in terms of acting appropriately when other unrelated painful episodes occur, such as blunt trauma or inflammation. Thermoregulation is also affected by chronic primary insomnia. Most notably, patients warm up faster in the morning and will therefore wake at earlier hours.

It is important to realize that the amount of sleep that an individual needs will change throughout his or her lifespan. Babies need 12-16 hours whereas adults need 7-8 hours. Older individuals sleep less at night, but in fact sleep about the same total hours as an average adult when daytime naps are included in total sleep time.

Even so, the golden rule among health professionals dictates that the quality of sleep as programmed by diverse orexin neurons far outweighs length of time. Many Americans believe they have insomnia when in fact they do not. “If an individual wakes in the middle of the night and is able to fall back asleep within 20 minutes, then he or she does not have insomnia,” explains sleep expert Dr. Jeffrey Young.