The effect of minocycline on symptoms in schizophrenia: Results from a randomized controlled trial

Schizophr Res. 2019 Apr;206:325-332. doi: 10.1016/j.schres.2018.10.023. Epub 2018 Nov 16.


Background: Studies have hypothesized that immunological abnormalities might contribute to schizophrenia, and basic science studies, as well as several clinical trials suggest that minocycline could be efficacious in ameliorating both positive and negative symptoms of schizophrenia. In this study we examined the effect of minocycline on schizophrenia in a large randomized controlled trial.

Methods: We performed a 16-week, multi-center, double-blind, randomized, placebo-controlled study on 200 subjects with schizophrenia or schizoaffective disorder randomized to receive either minocycline (200 mg/day, n = 100), or placebo (n = 100) as an add-on to anti-psychotic treatment. The primary outcome measure was the PANSS total score.

Results: Mixed models for repeated measures showed no significant difference between minocycline and placebo for total PANSS (p = 0.862), PANSS subscales, CGI or BACS.

Conclusions: Minocycline did not improve symptoms or cognition in schizophrenia.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Antipsychotic Agents / administration & dosage
  • Antipsychotic Agents / therapeutic use*
  • Cognition
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Minocycline / administration & dosage
  • Minocycline / therapeutic use*
  • Psychiatric Status Rating Scales
  • Psychotic Disorders / drug therapy*
  • Psychotic Disorders / physiopathology
  • Schizophrenia / drug therapy*
  • Schizophrenia / physiopathology
  • Schizophrenic Psychology
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Antipsychotic Agents
  • Minocycline

Associated data

  • EudraCT/2010-023982-23