Insomnia comorbidity and impact and hypnotic use by age group in a national survey population aged 16 to 74 years

Study Objectives: To compare age-group differences in somatic/psychiatric comorbidity, impact, and pharmacotherapy associated with sleep disturbance across a broad adult age range. Design: Cross-sectional national mental health survey. Setting: Adults living in private households in England, Scotland, and Wales. Participants: 8,580 people aged 16 to 74 years. Measurements and Results: Insomnia (4 symptom/syndrome definitions), depression, generalized anxiety disorder, and daytime fatigue were defined from the revised Clinical Interview Schedule. Any insomnia was reported by 37% of the sample, moderate insomnia by 12%, insomnia with fatigue by 13%, and symptoms fulfilling diagnostic criteria for primary/secondary insomnia by 5%. All categories of insomnia were associated with mental disorders, worse physical health, and fatigue to a similar degree in all decade age groups. The associations between insomnia categories and separated, divorced, or widowed marital status were strongest in younger participants. Insomnia categories were of longer reported duration and more strongly associated with worse physical health-related quality of life (SF-12) in older age groups. For participants with any definition of insomnia, benzodiazepine hypnotics were more commonly reported in older age groups. Conclusions: The association between insomnia and impaired quality of life is most pronounced in older age groups. Associations with physical and mental health status and those with daytime fatigue do not vary in strength between age groups. Older people with insomnia in this population were more likely to be taking benzodiazepine hypnotics.