even when controlling for the PSQI, PHQ-2, and DLQI (p = 0.1486). The GAGS in our study may have been more congruent with our patient’s self-reported acne severity had our patients been more severe as determined by the GAGS. This seems likely given that prior research has shown that a patient’s perception of their acne is directly correlated to the impact it has on their quality of life, and objective severity does not always correlate with the impact of the disease experienced by the patient [19,20].= Future research should include subjects with greater acne severity given the impact acne severity has on quality of life, stress, and mental health [13,16–18]. Further limitations of our study were its smaller sample size and the lack of a physiological measure of sleep quality (e.g., polysomnography). A power analysis was not performed for our study. Our sample size was determined based on review of similar research and the assumption that our Clocks&Sleep 2019, 1 513 sample would be normally distributed. Informed by our experience and findings, future studies with larger cohorts are necessary to both confirm our findings and to ascertain whether or not a type II error occurred for our non-significant findings due to a lack of power. Additionally, although the PSQI generates a standardized score, it still is based on self-reporting and may be less reflective of actual sleep disturbances [21]. Despite these limitations, our data and the data of others does suggest a complex relationship between sleep and acne. The relationship between acne and sleep quality are likely the consequence of a dynamic interplay between psychiatric and pathophysiologic factors given the correlation among DLQI, PHQ-2, and sleep quality. This is further supported by the correlation between sleep quality and objective acne severity rather than subjective severity demonstrated in this analysis. Insufficient sleep duration has been linked to numerous inflammatory systemic diseases, including diabetes, hypertension, obesity, psychiatric diseases, and increased all-cause mortality [17]. Several mechanisms have been postulated to explain these relationships. In one study, using in situ hybridization, facial skin biopsies from patients with acne were found to have higher expression of corticotropin-releasing hormone receptors in acne-involved sebaceous glands when compared with normal and uninvolved skin. These findings imply a role in stress-induced, sleep-related development and exacerbation of acne [22]. There are also numerous studies exploring the inter-relationship between the internal circadian clock and the commensal microbiome as it relates to host immune function as well as digestive and metabolic functions [23,24]. Studies have demonstrated greater metagenomic diversity of C. acnes in patients with acne vulgaris versus their healthy skin counterparts, and it would be interesting to investigate the influence of circadian function specifically on cutaneous C. acne populations [25]. The relationship among sleep disturbances, mental health, and the skin microbiome in patients with acne is an area for further investigation. This was a single-center, non-interventional research study conducted in the Department of Dermatology at University Hospitals Cleveland Medical Center in Cleveland, OH. The study received approval from the University Hospitals Institutional Review Board (IRB). There was no amendment to the trial protocol after it was initiated. 4.2. Recruitment and Study Population Patients were identified and invited to join the study through dermatology clinics, local advertisements, hospital-wide recruitment events, and our department’s own research patient database. Inclusion criteria required subjects to be 18 years of age or older, have acne vulgaris, be in general good health, able to provide informed consent, and able to comply with all study activities. Subjects were considered to be in “general good health” if life-threatening acute medical conditions (e.g., active infection, cancer, etc.) were absent, and chronic medical conditions (e.g., diabetes, hypertension, etc.) were well controlled based on investigator assessment. Women who were pregnant or actively nursing were excluded. Active