Objective: The composition of the gut microbiota varies significantly among healthy individuals, as well as insomniacs, hypersomniacs, and healthy people. On the other hand, a substantial bacterial strain is shared across these populations with distinct intra-population, mother-to-infant, and intra-household transmission patterns. Based on these premises, we propose a hypothesis stating that person-to-person bacterial transmission can change the sleep pattern in couples.

Patients and Methods: In this pilot study, 157 couples who had been married and living together for an average of 5.91 months were enrolled. A wide range of questionnaires were administered to participants to measure sleep patterns. Gut microbiota composition was analyzed at two-time points: baseline and 3 months later.

Results: Three months after the marriage, spouses with healthy sleep patterns were significantly more likely to resemble their insomniac or hypersomniac couples. Gut microbiota composition in participants with normal sleep patterns was significantly changed and became similar to that of the participant’s spouse, i.e., if the spouse was insomniac or hypersomniac, then gut composition became similar to his/her insomniac or hypersomniac spouse, respectively. The results of mediation analysis confirmed the association between the changes in the sleep pattern and changes in the gut microbiota. We provide for the first time evidence of gut microbial community structure alterations in newly married couples, which parallels reduced sleep quantity and quality.

Conclusions: The research will have important implications in terms of diagnosis and treatment of sleep disturbances through microbiota modulation, particularly from the perspective of diagnostic, predictive, preventive, and personalized medicine.