Objective: To determine whether subjects with insomnia report greater reductions in quality of life (QoL) than subjects without insomnia when assessed with self-report instruments.
Methods: Questionnaires were completed by individuals recruited through media advertisements and screened with a structured telephone interview. Data obtained from 261 individuals with insomnia (INS group) were compared with those of 101 individuals with no sleep complaint, or controls (CTL group).
Results: Subjects in the INS group obtained lower mean sum scores on the Medical Outcomes Study Cognitive Scale than did subjects in the CTL group (25.34 +/- 0.34 vs 31.91 +/- 0.58, t = 9.53, p < 0.0001). The INS group also obtained lower mean scores on all subscales of the SF-36 Questionnaire compared with those in the CTL group (each, p < 0.0001 or lower), indicating impairments across multiple QoL domains. Psychiatric assessment revealed that subjects in the INS group obtained significantly higher mean item scores than subjects in the control group on the Zung Depression Scale (2.22 +/- 0.03 vs. 1.52 +/- 0.03, p < 0.0001) and the Zung Anxiety Scale (1.96 +/- 0.02 vs. 1.40 +/- 0.04, p < 0.0001). In addition, subjects in the INS group reported significantly greater impairments in specific QoL domains on the QoL inventory, and the Work and Daily Activities Inventory. No differences were observed between subjects in the INS group who were receiving treatment for insomnia versus those who were untreated.
Conclusions: The results of this study indicate that significant QoL impairments are associated with insomnia.