title: Predicting adherence to medications using health psychology theories: a systematic review of 20 years of empirical research.
abstract: OBJECTIVE
  This review sought to identify the empirical evidence for the application of models from sociocognitive theory, self-regulation theory, and social support theory at predicting patient adherence to medications.
  
  
  METHODS
  A systematic review of the published literature (1990-2010) using MEDLINE, EMBASE, Cochrane Library, CINAHL, and PsychINFO identified studies examining the application of health psychology theory to adherence to medication in adult patients. Two independent reviewers extracted data on medication, indication, study population, adherence measure, theory, model, survey instruments, and results. Heterogeneity in theoretical model specification and empirical investigation precluded a meta-analysis of data.
  
  
  RESULTS
  Of 1756 unique records, 67 articles were included (sociocognitive = 35, self-regulation = 21, social support = 11). Adherence was most commonly measured by self-report (50 of 67). Synthesis of studies highlighted the significance (P ≤ 0.05) of self-efficacy (17 of 19), perceived barriers (11 of 17), perceived susceptibility (3 of 6), necessity beliefs (8 of 9), and medication concerns (7 of 8).
  
  
  CONCLUSIONS
  The results of this review provide a foundation for the development of theory-led adherence-enhancing interventions that could promote sustainable behavior change in clinical practice.
authors.affiliation: Centre for Health Economics & Medicines Evaluation. Electronic address: e.holmes@bangor.ac.uk.
authors.forename: Emily A F
authors.initials: EA
authors.lastname: Holmes
authors.affiliation: Centre for Health Economics & Medicines Evaluation.
authors.forename: Dyfrig A
authors.initials: DA
authors.lastname: Hughes
authors.affiliation: School of Psychology, Bangor University, Bangor, Gwynedd, UK.
authors.forename: Valerie L
authors.initials: VL
authors.lastname: Morrison
mesh_terms: D036262:Empirical Research; D015438:Health Behavior; D006801:Humans; D055118:Medication Adherence / Q000523:psychology*; D008960:Models, Psychological; D012944:Social Support
keywords: adherence; health psychology; medications; systematic review