Does Adherence to Antidepressants Impact Healthcare Costs Among Patients with Mood Disorders?

The objective of the study was to examine the effect of antidepressant adherence on healthcare costs in patients diagnosed with bipolar disorder, as well as in patients being treated for depression. Although not approved by the Federal Drug Administration, antidepressants are commonly prescribed to patients diagnosed with bipolar disorder.

This study included patients that were under 62 years of age who were being treated for a mood disorder and did not have cancer or HIV infection. The patients had to receive at least two prescriptions for an antidepressant between April 2007 and September 2008. The patients’ adherence level during that time period was measured by the medication possession ratio (MPR: the percentage of time the patient had access to the medication). Patients were classified by their MPR level as adherent (80% and higher), partially adherent (60% to 80%), or non-adherent (less than 60%). Total healthcare costs were then reviewed for an 18 month follow-up period by MPR group.

Of the 56,195 patients included in the study, 70% were diagnosed with depression and 10% with bipolar disorder. For the patients with depression, those who were fully or partially adherent to antidepressants had statistically significant lower healthcare costs than patients who were non-adherent. However, among patients diagnosed with bipolar disorder, there was no statistically significant difference in healthcare costs among the three adherence groups.

The results of this study add to earlier research questioning the use and effectiveness of antidepressants in the management of bipolar disorder.

Dr. David Muzina, Zhuliang Tao, Dr. Inderpal Bhandari and Dr. Steven Bowlin¹

Based on a study by the Medco Research Institute^TM presented at the 2010 American Psychiatric Association’s 62nd Institute on Psychiatric Services

¹Medco Health Solutions, Inc., Franklin Lakes, NJ