LAUSR

Background Minocycline has neurological anti-inflammatory properties and has been hypothesised to have antipsychotic effects. Aim The aim of this study was to investigate, using routinely collected United Kingdom primary health care data, whether adolescent men and women are more or less likely to receive an urgent psychiatric referral during treatment for acne with minocycline compared with periods of non-treatment. Method A self-controlled case series using United Kingdom Clinical Practice Research Datalink to calculate the incidence rate ratio of urgent psychiatric referrals for individuals, comparing periods during which minocycline was prescribed with unexposed periods, adjusted for age. Results We found 167 individuals who were at the time exposed to minocycline for a mean of 99 days and who received an urgent psychiatric referral. There was no difference in psychiatric referral risk during periods of exposure compared with periods of non-exposure: incidence rate ratio first 6 weeks of exposure 1.96, 95% confidence interval 0.82–4.71, p=0.132; incidence rate ratio remaining exposure period=1.97, 95% confidence interval 0.86–4.47, p=0.107. Conclusions We found no evidence in support of a protective effect of minocycline against severe psychiatric symptoms in adolescence.