Modifiable barriers and enablers of medication adherence among people with schizophrenia: A systematic review and theoretical synthesis

Background: Despite the efficacy of pharmaceutical treatment, medication adherence is reported to be as low as 40-50% among people with schizophrenia. The objectives of this review were to identify and synthesise evidence on modifiable barriers of pharmaceutical medication adherence among people with schizophrenia and generate recommendations for future interventions using Behaviour Change Techniques. Methods: The literature search included qualitative, quantitative, and mixed-methods research published in English from the database inception to May 2024. Three databases (MEDLINE, Embase, and PsycINFO) were searched to identify publications on the modifiable barriers. Data synthesis involved data extraction from included papers, which were then inductively synthesised by mapping onto the sub-components of the Theoretical Domains Framework (TDF) and the Capability, Opportunity and Motivation model of Behaviour. Results: 40 articles met the inclusion criteria. Nine themes were generated: (1) ‘Understanding of experiences’, (2) ‘Knowledge about medication’, (3) ‘Forgetting to take medication’, (4) ‘Relationship with healthcare professionals’, (5) ‘Beliefs about the necessity of taking medication’, (6) ‘Reflecting on past medication use experience’, (7) ‘Fear of side effects’, (8) ‘Feeling social stigma’, (9) ‘Ongoing social support from family/friends’. Six behavioural influences on medication adherence were identified via the TDF (Knowledge, Memory, attention and decision processes, Social/Professional role and identity, Beliefs about consequences, Emotions and Social influences). Conclusion: By highlighting modifiable behavioural influences, findings of this review can be used to inform evidence-based, person-centred approaches that support medication adherence. Potential interventions may involve improving access to information on treatment options, drawing on social support, and reviewing treatment plans to address side effects.