0312 Rumination and Sleep: A Gender-Differentiated Analysis

Abstract Introduction Chronic insomnia disorder (CID) is often accompanied by pre-sleep cognitive arousal, notably ruminative thought, which has been linked to poorer sleep quality by both objective and subjective sleep indicators. Rumination specifically has been consistently characterized as a cognitive symptom with a greater prevalence among women. We hypothesized that rumination would impact polysomnographic characteristics indicative of sleep quality more strongly in women than in men. Methods Twenty participants (nwomen=12, nmen=8) with insomnia symptoms completed 2 overnight in-lab stays to receive both an active and sham cTBS condition. Data for this abstract were extracted from the sham condition only (i.e., no intervention was administered). The Glasgow Content of Thoughts Inventory (GCTI) was administered at baseline and pre- and post-sham-stimulation assessments. For this data, GCTI scores closest to sleep (post-sham-stimulation) were used. Bivariate correlations were used to examine relationships between GCTI rumination scores and PSG sleep parameters in women and men separately. Parameters of sleep quality included sleep onset latency (SOL), N2 latency, and REM duration. Results In men, GCTI scores were not associated with PSG sleep parameters. In women, higher GCTI scores correlated with longer SOL (r = 0.728, p = 0.007,) and longer N2 latency (r = 0.782, p = 0.003,). No significant relationships were found between GCTI and REM duration in women. Conclusion Despite limited sample size, significant relationships were discovered between measures of pre-sleep rumination and PSG sleep parameters. Consistent with our hypothesis, pre-sleep mental activity was associated with difficulty falling asleep. Such cognitive activity may be disruptive to the early stages and overall stabilization of sleep, warranting further investigation into how this relationship fits into cognitive models of insomnia. Moreover, the association was only evident in women, suggesting that sex-specific differences influence the way pre-sleep rumination affects sleep. However, this difference might be an artifact of small sample size; future work will be needed to evaluate this possibility. These results highlight the potential importance of considering a sex-stratified approach to understanding associations between cognitive factors and sleep difficulties. Support (if any)