Psychosocial factors are strongly associated with insomnia in users and nonusers of prescribed sleep medication: evidence from the HUNT3 study

OBJECTIVE The aim of this study was to examine how neuroticism, stressful life events, self-rated health, life satisfaction, and selected lifestyle factors were related to insomnia both by sex and among users and nonusers of prescribed sleep medication (PSM). DESIGN Cross-sectional data from the Norwegian Nord-Trøndelag Health Study (HUNT3, 2006-2008), a population-based health survey, were linked to individual data from the Norwegian Prescription Database. METHODS Logistic regression analyses were used to investigate the associations between the selected variables and insomnia in both males and females and among subjects using and not using PSM. Individuals were considered to have a presumptive diagnosis of insomnia disorder if they reported difficulty with sleep initiation, sleep maintenance, or early morning awakening several days per week for the last 3 months. PSMs were categorized as anxiolytics or hypnotics; the dose was estimated according to defined daily dose (DDD). RESULTS Of the total 50,805 participants, 6,701 (13.2%) used PSM. The proportions of PSM users were larger among elderly participants. Increased risk of insomnia was strongly associated with poor self-rated health and higher level of neuroticism. These associations were evident for both sexes and were similar among both users and nonusers of PSM. Low satisfaction with life was strongly related to insomnia, but only among nonusers of PSM. Increased doses of PSM were not associated with reduced likelihood of insomnia. CONCLUSION Insomnia is a problem among both users and nonusers of PSM and is associated with psychosocial factors. Our findings suggest that successful treatment for sleep problems should take individual variation into account, such as age, sex, personality traits, satisfaction with life, and health perception.