Nonadherence With Mood Stabilizers: Prevalence and Predictors.

Background: The prevalence of nonadherence with mood stabilizers ranges from about 18% to 52%. Only 1% of publications on mood stabilizers address this issue. This study aimed to explore the prevalence and predictors of nonadherence in a cohort of individuals with affective disorders receiving long-term treatment with mood stabilizers.

Method: Subjects receiving lithium, carbamazepine, and/or valproate were identified from biochemistry laboratory data. Ninety-eight of these subjects had major depressive disorder (N=20) or bipolar disorder (N=78) (DSM-IV) and gave informed consent to participate in a structured clinical interview to assess their medication adherence and the factors that influenced it.

Results: Just under 50% of subjects (46/98) acknowledged some degree of medication nonadherence in the previous 2 years, and 32% (29/92) reported only partial adherence in the last month (missing 30% or more of their prescribed medication). Backward stepwise logistic regression demonstrated that partially adherent subjects were best distinguished from adherent subjects by a more frequent past history of nonadherence, denial of severity of illness, and greater duration of being prescribed a mood stabilizer.

Conclusion: Rates of mood stabilizer nonadherence are high. Attitudes and behaviors are better predictors of nonadherence than side effects from medication. Clinicians need to inquire routinely about problems with adherence.