The chance of developing major depressive disorder (MDD) is much higher in patients who have acne, according to a retrospective cohort analysis published as a research letter.

“The onset of acne, when patients present for treatment because of active disease, is associated with a greater risk of developing depression” wrote Isabelle A. Vallerand, an MD/PhD student at the University of Calgary (Alta.), and her associates. “Although the severity of acne was not assessed directly in the current study, this finding suggests a potential dose/response relationship such that more active disease may lead to a greater risk of depression.”

Ms. Vallerand and her colleagues conducted a retrospective cohort study using patient information collected from the Health Improvement Network (THIN), a database in the United Kingdom, from 1986 to 2012. All patients in the study were between the ages of 7 and 50 years, with one or more Read codes associated with acne. For comparison, a general population cohort without acne was established. All patients were then followed from their start date for 2 or more years until the first appearance of MDD. Patient baseline factors of age, sex, obesity, smoking status, alcohol use, comorbidities, and socioeconomic factors were measured.

In total, 134,437 acne patients and 1,731,608 patients without acne were identified from THIN. Over a 15-year follow-up, the probability of developing MDD was 18.5% among patients with acne, and 12% for those without acne. This risk was much higher within the first year after diagnosis (adjusted hazard ratio, 1.63; 95% confidence interval, 1.33-2), which subsequently decreased.

The researchers found that patients with acne tended to be younger (67.6% vs. 22.8%), female (58.6% vs. 48.6%), and of a higher socioeconomic status (24.4% vs. 22.1%) compared with patients without acne. Those with acne tended to smoke (58.4% vs. 48.6%) and to have comorbidities (17.2% vs. 13.8%). Conversely, acne patients were less likely to use alcohol (17% vs. 39%) and less likely to be obese (2.3% vs. 6.6%) (all P less than .001).

Although these results are promising, there are several limitations that could have influenced the study findings. The misclassification of patients with acne and MDD could have occurred if patients did not present themselves to a physician for treatment. Another limitation was that isotretinoin was the only acne treatment that was considered by the researchers. Considering that treatment has been shown to reduce depressive symptoms, the researchers believe that their estimates are conservative.

“Given the tremendous burden of MDD and its temporal association with active acne, it is critical that physicians monitor mood symptoms in patients with acne and initiate prompt MDD management or seek consultation from a psychiatrist when needed” wrote Ms. Vallerand and her colleagues.

Ms. Vallerand received funding for this study from the Alberta Innovates Health Solutions MD-PhD Studentship and from the Mach-Gaensslen Foundation of Canada. None of the other authors had disclosures to report.

SOURCE: Vallerand I et al. Br J Dermatol. 2018 Feb 7. doi: 10.1111/bjd.16099 .