Insomnia Subtypes in Depressive Disorders and their Relationship to Clinical Outcomes

Abstract

Objective : To investigate the insomnia subtypes found in patients with depressive disorders, those in both remission and non-remission groups.
Methods : This report describes the insomnia subtypes found in outpatients with depressive disorders after 3 months of treatment. Two hundred and twenty-four participants with depressive disorder were evaluated using the Hamilton Depressive Rating Scale (HAM-D) insomnia subscale at the baseline and at a three-month follow-up. The insomnia subtypes found at each of these points were compared. Clinical Global Impression was applied to define the presence or not of remission, and the influence of each insomnia subtype on HAM-D scores over time analyzed.
Results : Ninety-three percent of the participants were found to have insomnia. The most common subtype was simultaneous initial, middle and terminal insomnia, with 52% showing this subtype at the baseline, and 15% at the 3-month follow-up. The mean score for simultaneous early, middle and terminal
insomnia decreased more among those in the remitted group than in those from the non-remitted group (mean difference = -1.76, 95% CI = -0.24 to -1.19). All three subtypes were significant predictors of HAM-D scores over time (p < .0001) and the initial and terminal subtypes also appeared to have an
effect when interacting with time.
Conclusions : The most common subtype is simultaneous early, middle and terminal insomnia, the decrease in insomnia severity is related to remission among depressive disorders.