Age comparison of treatment adherence with antipsychotic medications among individuals with bipolar disorder.

Background: Few studies have evaluated medication adherence among older vs younger individuals with bipolar disorder (BPD). We compared adherence with antipsychotic medication among older (age 60 and older) and younger individuals using a large case registry (n = 73,964).

Methods: Adherence was evaluated using the medication possession ratio (MPR) for patients receiving antipsychotic medication.

Results: Twenty six thousand five hundred and thirty younger individuals (mean age 46.9) and 6,461 older individuals (mean age 69.2) were prescribed antipsychotic medication. Among older individuals, 61.0% (n = 3,350) were fully adherent, while 19.0% (n = 1,043) were partially adherent and 20.0% (n = 1,098) were non-adherent. Among younger individuals, 49.5% (n = 10,644) were fully adherent, while 21.8% (n = 4,680) were partially adherent, and 28.7% (n = 6,170) were non-adherent. As with younger patients, comorbid substance abuse and homelessness predicted non-adherence among older patients with BPD.

Conclusion: Older individuals with BPD were more adherent with antipsychotic medications compared to younger individuals. However, a substantial proportion (approximately 39%) of older patients with BPD still have difficulties with adherence.