Sleep polysomnography as a predictor of recurrence in children and adolescents with major depressive disorder

Adults with major depressive disorder (MDD) demonstrate certain sleep polys omnographic abnormalities, including sleep continuity disturbances, reduced slow-wave sleep, shortened rapid eye movement (REM) latency, and increased REM density. Findings of sleep EEG studies in depressed children and adole scents have yielded conflicting results, possibly because of methodological variations across the studies. Generally, however, studies have demonstrat ed that depressed children and adolescents exhibit less sleep continuity an d non-REM sleep differences in comparison with control subjects than do adu lts. Thus, results from adult sleep polysomnography studies cannot necessar ily be generalized to children and adolescents. Depressed adults who have r educed REM latency during the symptomatic episode appear more likely to hav e a relapse once treatment is discontinued than those with normal REM laten cy. No studies of the relationship between sleep polysomnographic variables and clinical course have been reported in depressed children and adolescen ts. Data for baseline clinical variables and 3 nights of sleep polysomnogra phy were examined in 113 depressed children (less than or equal to 12 yr: n = 51) and adolescents (greater than or equal to 13 yr; n = 62) (56 in-pati ents and 57 outpatients) where data was available on at least I yr of natur alistic follow-up. Subjects came from 2 studies of sleep polysomnography in children and adolescents with MDD. Clinical course was assessed using the Kiddie-Longitudinal Interval Follow-Up Evaluation IK-LIFE). This interview was used to define recovery from the index episode of MDD and recurrence, a new episode of meeting hill criteria for MDD. Clinically within 1 yr of in itial evaluation 102/113 subjects had recovered from their index episode of depression (minimal or no symptoms for 60 d). Of the 102 subjects who reco vered, 36 (35.3 %) had a recurrence of MDD. The majority of subjects (55 %) who had a recurrence were not on medication at the time of recurrence. Sub jects who had a recurrence were more likely to report suicidal thoughts or attempts at baseline compared to those without a recurrence (67 vs. 37%; F = 8.77; p = 0.004). On baseline sleep polysomnography, subjects with a late r recurrence had decreased sleep efficiency and delayed sleep onset (sleep latency > 10 min). Probability of recurrence at 12 months was 0.39 compared to 0.15 in subjects with non-delayed sleep onset (p = 0.005). Baseline sui cidal ideation and sleep dysregulation on sleep polysomnography predicted r ecurrence in a large sample of depressed children and adolescents. Depressi on in children and adolescents is frequently a chronic, recurrent illness. Factors that can predict clinical course are important in increasing our un derstanding of depression in this age group.