Non-adherence to mood stabilizers and antipsychotics among persons with bipolar disorder – A nationwide cohort study

Abstract

BackgroundNon-adherence to medications is common in bipolar disorder but its prevalence estimations have varied significantly. In addition, non-adherence is known to increase the risk of poor clinical outcomes. Therefore, we studied how common primary non-adherence for mood stabilizers and antipsychotics is in Finland and which factors are associated with it. MethodsNationwide sample of persons diagnosed with bipolar disorder during 1987–2018 were identified from registers. Dispensings of their electronic prescriptions during 2015–2018 were followed up to define rates of primary non-adherence. Primary non-adherence was defined as having at least one non-dispensed mood stabilizer or antipsychotic prescription during 2015–2018. In a broader definition, non-adherence was defined as having ≥20 % of mood stabilizer and/or antipsychotic prescriptions non-dispensed. Adjusted logistic regression was used to assess risk factors for non-adherence. ResultsThe study cohort included 33,131 persons and 59.1 % had at least one non-dispensed mood stabilizer or antipsychotic prescription. 31.0 % of the cohort was non-adherent to ≥20 % of their mood stabilizer and/or antipsychotic prescriptions. Lithium and clozapine had the lowest proportions of non-dispensed prescriptions. Especially young age, recent bipolar disorder diagnosis, multiple hospitalizations due to bipolar disorder, and use of benzodiazepines or antidepressants were associated with an increased risk of non-adherence. LimitationsThis study was based on register data, and patient-reported reasons for medication non-adherence could not be included. ConclusionsThe majority of patients with bipolar disorder do not use their medications as prescribed. Patient-specific risk for non-adherence should be assessed and those at high risk for non-adherence should be followed closely.