Multivariable adjusted odds ratio (95% CI) associating partially remitted insomnia and persistent insomnia with sociodemographic, medical, and behavioral factors as compared to fully remitted insomnia
Interestingly, behavioral factors (i.e., caffeine, cigarettes, and alcohol consumption) were not significantly associated with the remission or persistence of insomnia. Furthermore, SDB did not predict the persistence of insomnia. These results remained unchanged even if we used a more severe threshold (AHI ≥ 15) to define SDB.
Because of the observed effects of mental health problems on the persistence of insomnia, we further examined in a subsample of subjects that completed the MMPI-2 at baseline whether differences existed in terms of the personality profile of the 4 study groups while controlling for potential confounders. The groups of persistent insomnia and/or partially remitted insomnia showed significantly higher elevations in all MMPI-2 scales when compared to normal sleepers. In contrast, in the group with fully remitted insomnia, only hypochondriasis and depression were significantly higher than the group with normal sleep. Furthermore, the group of persistent insomnia and/or partially remitted insomnia had significantly higher elevations in 2 scales (i.e., 6-Paranoia and 9-Hypomania) compared to the group of fully remitted insomnia.