Some limitations of the study include the use of self-reporting to measure insomnia, depression, and anxiety; the measurement of only morning salivary cortisol levels; and the researchers' failure to control for shared lifestyle factors such as diet. Additionally, due to financial restraints, bacterial samples were only collected from the tonsils and pharynx, rather than the full oral microbiome.

Nonetheless, the study raises some interesting questions for future research.

“Since this study is associational, further research is needed to establish whether this association is causal,” the researchers said. “If it is determined that this association is indeed causal, it could have significant implications for contemporary research.”