The use of isotretinoin to treat acne was not associated with an increase in adverse neuropsychiatric outcomes, compared with the use of oral antibiotics, in a large retrospective cohort study published in the British Journal of Dermatology.

Although severe neuropsychiatric effects associated with isotretinoin therapy in patients with acne have been reported, “the evidence base ... is mixed and inconclusive,” and many studies are small, Seena Fazel, MBChB, MD, of the department of psychiatry, Oxford University, England, and co-authors write in the study.

The study results suggest that isotretinoin is conferring protection against adverse neuropsychiatric outcomes, particularly when compared with using oral antibiotics to treat acne, Dr. Fazel, professor of forensic psychiatry at Oxford University and the study’s senior author, said in an interview.

In the study, the investigators reviewed electronic health records (2013-2019) from a primarily United States–based dataset (TriNetX) of patients with acne aged 12-27 who had been followed for up to 1 year after their prescriptions had been dispensed.

There were four arms: those prescribed isotretinoin (30,866), oral antibiotics (44,748), topical anti-acne treatments (108,367), and those who had not been prescribed any acne treatment (78,666). The primary outcomes were diagnoses of a neuropsychiatric disorder (psychotic, mood, anxiety, personality, behavioral, and sleep disorders; and non-fatal self-harm) within one year of being prescribed treatment.

After using propensity score matching to adjust for confounders at baseline, the investigators determined that the odds ratio for any incident neuropsychiatric outcomes among patients with acne treated with isotretinoin was 0.80 (95% confidence interval, 0.74-0.87), compared with patients on oral antibiotics; 0.94 (95% CI, 0.87-1.02), compared with patients on topical anti-acne medications; and 1.06 (95% CI, 0.97-1.16), compared with those without a prescription for anti-acne medicines.

Side effects of isotretinoin – such as headache, dry mouth, and fatigue – were higher among those on isotretinoin than in the other three groups.

The authors concluded that isotretinoin was not independently linked to excess adverse neuropsychiatric outcomes at a population level. “We observed a consistent association between increasing acne severity as indicated by anti-acne treatment options and incidence of adverse neuropsychiatric outcomes, but the findings showed that isotretinoin exposure did not add to the risk of neuropsychiatric adverse outcomes over and above what was associated with oral antibiotics,” they write.

Isotretinoin treatment “appeared to mitigate the excess neuropsychiatric risk associated with recalcitrant moderate-to-severe acne,” they add.

The dermatology community has been interested in the impact isotretinoin has on mental health, and “I think clinically, they see that people get better on isotretinoin and their mental health improves,” Dr. Fazel told this news organization.

Asked to comment on the study results, John Barbieri, MD, MBA, director of the Advanced Acne Therapeutics Clinic, Brigham and Women’s Hospital, Boston, commended the investigators for the design of the trial.

“One of the strengths of this study is that they use a technique called propensity-score matching, where you try to make the groups of patients similar with respect to their other characteristics to minimize the risks of confounding and bias in the study, which I think is a real strength,” he told this news organization. “The other thing that they do, which I think is a strength, is to think about the impact of acne severity on these outcomes, because we know acne itself is associated with depression and risk for suicide and other neuropsychiatric outcomes.”

Including a cohort of patients who had acne and received oral antibiotics for comparison “is a nice way to address the potential for confounding by severity and confounding by indication,” Dr. Barbieri said. “Those who get antibiotics usually have more severe acne. They may not have it as severely as those who get isotretinoin, but it is a nice approach to account for background levels of depression and neuropsychiatric outcomes in patients with acne. I think that is a real strength of the study. This is one of the best studies to have looked at this question.”

However, although the study found that isotretinoin decreased the excess psychiatric risk associated with refractory moderate-to-severe acne, it does not rule out the possibility that individuals may experience an adverse psychiatric outcome while on isotretinoin, Dr. Barbieri said.

“While I think on a population level, we absolutely can feel reassured by these data, I do think there are individual patients who have idiosyncratic, unpredictable reactions to isotretinoin where they have mood changes, whether it be irritability, depression, or other mood changes,” he cautioned. “Given the association of acne itself with mental health comorbidities, it is important to screen for comorbidities such as depression in all patients with acne.”

The study was funded by the Wellcome Trust, which provided Dr. Fazel and the first author with financial support for the study. One author is an employee of TriNetX; the other authors had no relevant disclosures. Dr. Barbieri reported no financial disclosures. He is cochair of the AAD’s Acne Guidelines Workgroup and associate editor at JAMA Dermatology.

A version of this article first appeared on Medscape.com.

Study provides new analysis of isotretinoin and risk for adverse neuropsychiatric outcomes