Medication Adherence and Persistence in Patients with Severe Major Depressive Disorder with Psychotic Features: Antidepressant and Second-Generation Antipsychotic Therapy Versus Antidepressant Monotherapy

BACKGROUND: Major depressive disorder with psychotic features, or psychotic depression, is a severe mental health disorder often associated with a worse depression-related symptom profile when compared with major depressive disorder without psychotic features. While combination pharmacotherapy with an antidepressant and an antipsychotic is recommended as first-line therapy, antidepressant monotherapy has been found to be useful and efficacious in psychotic depression. OBJECTIVE: To assess the rates of antidepressant adherence and antidepressant persistence in Texas Medicaid patients with psychotic depression who used antidepressant plus second-generation antipsychotic (AD/SGA) therapy or antidepressant (AD) monotherapy. METHODS: Using Texas Medicaid prescription and medical claims data from September 2007 to December 2012, adult patients aged 18-63 years were included if they had no confounding psychiatric disorders, no antidepressant claims during a 6-month pre-index period, and at least 1 diagnosis for severe major depressive disorder with psychotic features (ICD-9-CM codes 296.24 and 296.34). The first claim date for an antidepressant served as the index date. All patients were required to have at least 2 antidepressant claims, and those in the AD/SGA cohort were required to have 2 or more claims for an SGA. Study covariates included age, gender, race/ethnicity, residence, Charlson Comorbidity Index (CCI) score, and tobacco use/dependence. Statistical analyses included descriptive statistics, univariate analyses, logistic regression, and Cox proportional hazards regression. RESULTS: A total of 926 patients met study criteria (AD cohort = 510; AD/SGA cohort = 416). The overall sample had a mean [±SD] age of 40.5 [±13.2] years and was primarily female (66.8%) and non-Caucasian (74.8%). When compared with the AD cohort, patients in the AD/SGA cohort had a 52.3% higher likelihood of being adherent to antidepressant therapy based on proportion of days covered (PDC; OR = 1.523; 95% CI = 1.129-2.053; P = 0.006). Similarly, antidepressant adherence was 42.0% higher for the AD/SGA cohort based on medication possession ratio (MPR; OR = 1.420; 95% CI = 1.062-1.898; P = 0.018). Younger patients, African Americans, and tobacco users/dependents had significantly worse likelihoods of antidepressant medication adherence based on PDC and MPR. The risk of antidepressant nonpersistence was 23.2% lower for patients in the AD/SGA cohort (HR = 0.768; 95% CI = 0.659-0.896; P = 0.001), compared with those in the AD cohort. Antidepressant nonpersistence was significantly higher in younger patients, African Americans, Hispanics, and tobacco users/dependents. CONCLUSIONS: Better antidepressant adherence and persistence outcomes were associated with combination pharmacotherapy with an AD and an SGA antipsychotic. This study provides real-world estimates that support the current first-line treatment recommendations for psychotic depression; however, it should be noted that the majority of study patients used AD therapy only. Future research in psychotic depression is needed.