Unstable sleep and rest-activity rhythms in adolescents at-risk for bipolar disorder: Links to mood symptoms and the effect of sleep stabilization.

BACKGROUND

Adolescents with a parental history of bipolar disorder (BD; High-Risk) are more likely to develop BD than those without such history (Low-Risk). Actigraphy studies in adults indicate that instability in sleep and rest-activity rhythms (RAR) may be associated with progression to BD. However, it remains unclear whether High- and Low-Risk adolescents are differentially affected by sleep and RAR instability and their impact on emerging mood symptoms.

METHODS

We recruited 50 adolescents unaffected by BD (mean age[SD] = 15.97[1.31], 58% female) stratified into High-Risk (N = 22) and Low-Risk (N = 28) groups. All participants completed two weeks of Baseline actigraphy; a subset of 11 High-Risk participants then completed a two-week sleep stabilization Manipulation at home targeting regular sleep timing and duration. Depression and mania rating scales were collected at Baseline and post-Manipulation. We examined between-group differences in sleep duration variability, midsleep variability, and Circadian Function Index (CFI; measure of circadian activity robustness), tested group moderation of associations with mood symptoms, and examined effects of the sleep stabilization protocol.

RESULTS

We found no between-group-differences (P-values>0.05). Among High-Risk participants only, greater sleep duration variability was linked to higher levels of depressive (β[95%CI] = 0.012[0.006,0.018]) and mania (β[95%CI] = 0.011[0.003,0.019]) symptoms, and lower CFI was linked to greater mania symptoms (β[95%CI] = -8.236[-12.525,-3.940]). The sleep stabilization protocol reduced sleep duration (P < 0.001) and midsleep (P = 0.005) variability and improved CFI (P = 0.044), with trend-level reductions in subthreshold mania symptoms.

CONCLUSIONS

These findings highlight that sleep and RAR instability may have a stronger impact on mood in High-Risk adolescents but simple behavioral interventions stabilizing sleep and rhythms could buffer against BD risk.