The quality of interactions among married couples is affected by wives’ inability to fall asleep at night, but not by husbands’ sleep problems, suggests new research.

Results show that, among wives, taking longer to fall asleep at night predicted their reports of more negative and less positive marital interactions the next day, and it also predicted their husbands’ reports of less positive marital interaction ratings the following day. In contrast, husbands’ sleep did not affect their own or their wives’ reports of next day’s marital interactions.

"We found that wives’ sleep problems affect their own and their spouses’ marital functioning the next day, and these effects were independent of depressive symptoms," said principal investigator Wendy M. Troxel, PhD, assistant professor of psychiatry at the University of Pittsburgh School of Medicine. "Specifically, wives who took longer to fall asleep the night before reported poorer marital functioning the next day, and so did their husbands."

The relationship between nightly sleep and next day’s marital interactions was stronger than the association between daily marital interactions and subsequent sleep. Curiously, however, husbands’ reports of higher levels of positive marital interactions predicted their own shorter sleep duration the next night.

The study involved 32 healthy, married couples with an average age of 32 years. Participants were free of clinically relevant sleep, psychiatric, or medical disorders. Sleep latency, wakefulness after sleep onset, and total sleep time were measured by actigraphy for 10 nights. The quality of marital interactions was assessed daily over the 10-day assessment using electronic diaries to evaluate positive marital interactions such as feeling supported or valued by spouse, as well as negative marital interactions such as feeling criticized or ignored by spouse. Dyadic, time series analyses helped determine the direction of the relationship between sleep and marital interactions.

According to the authors, the findings show that sleep disorders such as insomnia can have a negative impact on marital relationships.

"These results highlight the importance of considering the interpersonal consequences of sleep and sleep loss," said Troxel.

The study was supported by the National Institutes of Health through the National Heart, Lung, and Blood Institute; and the Clinical & Translational Science Awards. It was presented at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).