Our study showed that, on univariate analysis, self-reported acne severity scores are directly correlated with poorer quality of life and depressive symptoms (DLQI: r = 0.44677, p = 0.0039; PHQ-2: r = 0.33512, p = 0.0345). On multivariate analysis, when controlling for DLQI and PHQ-2, the average subjective sleep score decreased (i.e., worsened) as the objective acne severity score (GAGS) increased and vice versa (p = 0.0306, parameter estimate = −0.09003). In 2015, a French study demonstrated that there is a strong positive correlation between acne and fatigue upon waking (i.e., poor sleep quality) even when adjusting for age (p < 0.0001). It also demonstrated stressed patients have greater fatigue upon waking (p < 0.0001) and are more likely to have acne (OR = 1.975; p < 0.0001) . Although fatigue may be a symptom of depression and patients whose quality of life has been more severely impacted by acne are more stressed, our research demonstrates that, when controlling for depressive symptoms and quality of life impact, subjectively worse sleep quality is associated with objectively worse acne [13,16]. This suggests that there may be an influence of acne severity on subjective sleep quality and vice versa, confirming prior findings of the impact acne has on quality of life and mental health [13,16,17,18].
Our data did not establish a correlation between the PSQI and either subjective (r = 0.19349, p = 0.2316) or objective (GAGS; r = −0.14822, p = 0.3614) scores of acne severity. There was also no correlation (p = 0.2271) between the PSQI and GAGS even when controlling for the DLQI and PHQ-2 like there was for average subjective sleep scores and GAGS. In addition, it is interesting to note that there was no correlation (r = 0.21182, p = 0.1895) between self-reported acne severity and GAGS, 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 [13,16,17,18].
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 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 .
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 . 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 .
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 . The relationship among sleep disturbances, mental health, and the skin microbiome in patients with acne is an area for further investigation.