Reducing stigma towards incarcerated populations: a systematic review of intervention studies

To evaluate the effectiveness of interventions aimed at reducing stigma or discrimination against people with lived experience of incarceration (PLEIC), and to assess the role of 'Key Active Ingredients (KAI)' in influencing changes in stigma-related knowledge, attitudes and behaviours. Systematic review (registered with PROSPERO CRD42024508685). MEDLINE, Emcare, EMBASE, PsycINFO, HeinOnline, Sociology Source Ultimate and Web of Science were searched from January 2010 to September 2024. Included studies were intervention-based, published in English from 2010 to present, where at least one primary or secondary outcome was stigma-related. There were no restrictions on context, type or level of stigma or study populations. We adapted the KAI model for effective anti-stigma interventions as an a priori framework. An 'Active Ingredient Score (AIS)' was developed to measure the impact of KAIs on each anti-stigma intervention. Quality assessment was conducted using the Cochrane Collaboration's Risk of Bias and the Joanna Briggs Institute Meta-Analysis of Statistical Assessment and Review Instrument. 3926 articles were screened, of which 16 were included, covering 8815 participants across five countries. No studies from low or middle-income countries were found. 12 studies investigated the post-intervention impact on knowledge (positive=11), 12 investigated the impact on attitude (positive=10) and 8 investigated the impact on behaviour (positive=2) towards PLEIC. Of the eight KAIs, only 'myth-busting' correlated with greater post-intervention effects on knowledge and attitudes. Both online and face-to-face interventions were equally effective. Overall, study methods were strong for the included randomised control trials (n=3), but weak to moderate for the non-randomised interventions (n=13). Anti-stigma interventions are highly effective at impacting stigma-related knowledge and attitudes towards PLEIC, with myth-busting emerging as an important component. More research, particularly involving women and adolescents, is needed to identify ways to achieve positive impacts on stigma-related behaviour, with longer study follow-up durations.