Correlates of general quality of life are different in patients with primary insomnia as compared to patients with insomnia and psychiatric comorbidity

Chronic insomnia is known to have a negative influence on quality of life (QOL). To date, most studies on chronic insomnia have focused on health-related aspects of QOL. General QOL, which is a different construct, has not been studied in detail. Moreover, it is not known which factors are associated with general QOL in insomnia, and whether the presence of mental disorders, a condition known as comorbid insomnia, affects these variables. The present study focused on identifying sleep and psychosocial variables that might be associated with general QOL in primary and comorbid insomnia. Personality traits, coping variables, anxiety and depressive symptoms, fatigue and subjective sleep variables were assessed in 218 consecutive well-characterized patients with primary and comorbid insomnia, referred to a third line centre for sleep medicine. In primary insomnia, higher extraversion and lower discrepancies in social support were associated with higher QOL. Surprisingly, insomnia severity was not significantly associated with QOL in this group. However, lower fatigue, which can be seen as an important daytime consequence of insomnia was correlated with higher QOL in patients with primary insomnia. In both insomnia groups, low anxiety and depressive symptoms and low fatigue were associated with higher general QOL. In contrast with the primary insomnia group, lower insomnia severity was correlated with higher QOL in patients with comorbid insomnia. These results stress the importance of assessing and treating daytime fatigue in insomnia. In primary insomnia, improving social support might be an important treatment goal. Furthermore, this study supports the concept that treatment of insomnia should not be neglected in patients with comorbid insomnia. Indeed, both insomnia and indices of psychiatric disease are strongly associated with general QOL in this condition.