Minocycline as an adjunct for treatment-resistant depressive symptoms: A pilot randomised placebo-controlled trial

Muhammad I. Husain, Imran B. Chaudhry, Nusrat Husain, Ameer B. Khoso, Raza R. Rahman, Munir M. Hamirani, John Hodsoll, Inti Qurashi, John F.W. Deakin, Allan H. Young

Research output: Contribution to journalArticlepeer-review


Background: Evidence suggests that anti-inflammatory medication may be effective in the treatment of depressive symptoms. In this study, we aimed to investigate whether minocycline added to treatment as usual (TAU) for 3 months in patients with treatment-resistant depression will lead to an improvement in depressive symptoms. Methods: Multi-site, 12-week, double-blind, placebo-controlled, pilot trial of minocycline added to TAU for patients suffering from DSM-5 major depressive disorder, whose current episode has failed to respond to at least two antidepressants. The primary outcome measure was mean change in Hamilton Depression Rating Scale (HAMD-17) scores from baseline to week 12. Secondary measures were the Clinical Global Impression scale (CGI), Patient Health Questionnaire-9 (PHQ-9), the Generalised Anxiety Disorder scale (GAD-7) and EuroQoL (EQ-5D) quality-of-life questionnaire. Side-effect checklists were also used. Minocycline was started at 100 mg once daily (OD) and increased to 200 mg after 2 weeks. Results: A total of 41 participants were randomised, with 21 in the minocycline group and 20 in the placebo group. A large decrease in HAMD scores was observed in the minocycline group compared to the placebo group (standardised effect size (ES) -1.21, p < 0.001). CGI scores in the minocycline group also showed a large improvement compared with placebo (odds ratio (OR): 17.6, p < 0.001). PHQ-9, GAD-7 and EQ-5D total showed more moderate improvements (ES ∼ 0.4-0.5). Conclusion: The findings indicate that adjunctive minocycline leads to improvement in symptoms of treatment-resistant depression. However, our findings require replication in a larger sample.

Original languageEnglish
Pages (from-to)1166-1175
Number of pages10
JournalJournal of Psychopharmacology
Issue number9
Early online date31 Aug 2017
Publication statusPublished - 1 Sept 2017


  • depression
  • Inflammation
  • minocycline


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