The study, authored by Jason C. Ong, PhD, and colleagues at Stanford University, consisted of 312 patients, who were categorized as morning, intermediate and evening chronotypes based upon scores on the Morningness-Eveningness Composite Scale. Group comparisons were made on self-report measures of nocturnal sleep, sleep period variability and waking correlates and consequences of insomnia.

Compared to the morning and intermediate types, people with insomnia who prefer evening activities (i.e., “night owls”) reported the most sleep/wake irregularities and waking distress, even after adjusting for severity of sleep disturbance.

“Our findings indicate that further research should investigate the relationship between circadian rhythms and insomnia, especially with the severity of the ‘night owl’ group,” said Ong. “These factors may serve to perpetuate the insomnia disorder, and might be particularly important to consider when treating this subgroup of insomniacs.”

Insomnia, a classification of sleep disorders defined by difficulty falling asleep or staying asleep, waking up too early, or poor quality sleep, is the most common sleep complaint at any age. About 30 percent of adults have symptoms of insomnia.

The amount of sleep a person gets affects his or her physical health, emotional well-being, mental abilities, productivity and performance. Recent studies associate lack of sleep with serious health problems such as an increased risk of depression, obesity, cardiovascular disease and diabetes.

Experts recommend that adults get between seven and eight hours of sleep each night to maintain good health and optimum performance.

Those who think they might have insomnia, or another sleep disorder, are urged to discuss their problem with their primary care physician, who will issue a referral to a sleep specialist.

Source: American Academy of Sleep Medicine