Promoting treatment adherence in patients with bipolar disorder
Consider your patients’ perspectives and goals when choosing interventions
BD adherence studies
Treatment adherence in BD is challenged by the chronic remission-relapse pattern of the disorder. Manic episodes carry the highest risk of nonadherence.2 Scott and Pope8 evaluated self-reported adherence to mood stabilizers (lithium, carbamazepine, or valproate) among 98 patients with major depressive disorder and 78 with BD. They found that 32% of patients were partially adherent (defined as having missed >30% of doses in the past month) and >60% of these patients had sub-therapeutic plasma levels of mood stabilizers.
In a study of 106 BD outpatients treated with lithium who completed scales regarding their attitudes toward and knowledge of lithium and the Medication Adherence Rating Scale (MARS), 86% of patients had a therapeutic serum lithium level (.6 to 1.2 mEq/L), and knowledge of lithium was correlated with adherence.9 Jónsdóttir et al10 looked at medication adherence among 280 patients with schizophrenia and BD by comparing patient self-reports to provider reports and measuring serum drug concentrations; adherence was defined as having a serum concentration within the reference level for the specific medication. BD patients had an adherence rate of 66%, and self-reported adherence as measured by MARS and provider reports correlated with serum concentrations.
In a study of 71 adolescents with BD followed for 1 year after their first hospitalization for a manic or mixed episode, DelBello et al11 defined nonadherence as taking medication <25% of the time and partial adherence as taking medication 25% to 75% of the time. They found that 42% of patients were partially adherent and 23% were nonadherent.
Strakowski12 followed 46 adults from Taiwan and 96 from the United States for 1 year after their first manic or mixed episode and found that 79% of the Taiwanese patients and 50% of U.S. patients were adherent. Using the medication possession ratio (MPR)—which is calculated based the number of days between expected and actual prescription refills—to determine adherence, Sajatovic13 found that 54% of 44,637 veterans being treated for BD with lithium or anticonvulsants were fully adherent (MPR >.80), 25% were partially adherent (MPR >.50 to .80), and 21% were nonadherent (MPR ≤.50). In a survey of 131 randomly selected psychiatrists and 429 of their adult BD patients, Baldessarini14 found that 34% of patients reported missing ≥1 medication dose in past 10 days, but psychiatrists recognized only 18% of patients as nonadherent.
What affects adherence?
Although all BD patients share the same diagnosis, the factors that ultimately result in their medication adherence are as variable as the individuals themselves. Patients’ age, sex, culture, symptom severity, worldview, socioeconomic status, opinion of mental illness, and self-image influence their individual decisions on adhering to a prescribed medication regimen.1,15
Perception of medication efficacy. Not surprisingly, if a medication does not seem to decrease debilitating symptoms, a patient is unlikely to continue taking it. Patients with BD feel more affected by depressive symptoms than by manic symptoms, and have indicated that they are more likely to adhere to and view as successful treatments that reduce depressive symptoms.16,17
Tolerability. In an Internet-based survey, 469 patients with BD indicated that medication-related weight gain and cognitive impairment were the most important factors that affected adherence.16 Individuals’ concerns about possible side effects may contribute more to nonadherence than actually experiencing side effects.17 Concerns about long-term metabolic side effects from atypical antipsychotics also may limit adherence.17
Neurocognitive impairment. Whether caused by BD, aging, or a combination of these factors, deficits in memory, attention, and executive functioning can lead to unintentional nonadherence. In a study that assessed medication management ability among middle-aged and older adults, patients with BD were found to make 2.8 times more errors than healthy controls.18
Therapeutic alliance and psychoeducation. Patients’ expectations for pharmacotherapy vary from specific symptom relief to hopes for a complete cure, and their fears may be influenced by media and advertisements.17 Nonetheless a positive therapeutic alliance with the treating provider improves illness outcomes.19
A clinician’s ability to help patients build insight is invaluable for their current and future treatment. In a survey of 435 veterans with BD, nonadherence was greater among patients with limited insight about the role of medication in their illness.20 A study of 65 BD patients that evaluated insight into medication adherence at initial interview and 1 year later found that difficulty with adherence at the initial interview predicted future nonadherence and was correlated with lack of insight.21 Rosa et al9 found that BD patients in denial of their illness and those who had little psychoeducation were more frequently nonadherent with lithium treatment.
