Abstract
Background Most research on interventions to counter stigma and discrimination has focused on shortterm outcomes and has been conducted in highincome settings. Aims To synthesise what is known globally about effective interventions to reduce mental illnessbased stigma and discrimination, in relation first to effectiveness in the medium and long term (minimum 4 weeks), and second to interventions in lowand middleincome countries (LMICs). Method We searched six databases from 1980 to 2013 and conducted a multilanguage Google search for quantitative studies addressing the research questions. Effect sizes were calculated from eligible studies where possible, and narrative syntheses conducted. Subgroup analysis compared interventions with and without social contact. Results Eighty studies (n = 422 653) were included in the review. For studies with medium or longterm followup (72, of which 21 had calculable effect sizes) median standardised mean differences were 0.54 for knowledge and-0.26 for stigmatising attitudes. Those containing social contact (direct or indirect) were not more effective than those without. The 11 LMIC studies were all from middleincome countries. Effect sizes were rarely calculable for behavioural outcomes or in LMIC studies. Conclusions There is modest evidence for the effectiveness of antistigma interventions beyond 4 weeks followup in terms of increasing knowledge and reducing stigmatising attitudes. Evidence does not support the view that social contact is the more effective type of intervention for improving attitudes in the medium to long term. Methodologically strong research is needed on which to base decisions on investment in stigmareducing interventions. Copyright © 2015 The Royal College of Psychiatrists, unless otherwise stated.