The $290 billion that poor medication adherence costs the U.S. economy every year cuts across every imaginable disease state, but one in which it can be particularly problematic is mental health.
According to pharmacy benefit manager Express Scripts, depression accounts for more than $83 billion in medical costs every year, making it a major cause of disability. According to the National Institute of Mental Health, major depressive disorder affects 6.7% of adults in the United States per year, while 11.2% of adolescents experience the disorder at some point between the ages of 13 and 18 years.
One study conducted by Express Scripts and published in the Journal of Managed Care Pharmacy found that patients with depression who started therapy with generic drugs were as likely to remain adherent as those who started on branded drugs. The study — which analyzed data on antidepressant usage from more than 16,000 patient records in Express Scripts’ MarketScan database — showed that patients who started with generic versions of selective serotonin reuptake inhibitors and selective norepinephrine reuptake inhibitors had a therapy-discontinuation rate of 44.2%, compared with 46.8% among those taking branded SSRIs and SNRIs. But at the same time, drug costs for those taking generics were almost 50% lower, and total healthcare costs were approximately 20% lower, costing an average of $3,660 for patients starting on a generic and $4,587 for those starting on a branded drug.
Depression as a side effect of medications can affect adherence as well, such as with interferons used to treat hepatitis C. According to a 3,607-patient study conducted by PBM Medco Health Solutions in April, adherence among hepatitis C patients may improve when they take antidepressants in addition to their interferons. “A common side effect of interferon use is depression, but little research has been done looking at the impact of treating depression on a patient’s adherence with their hepatitis C medications,” Medco Advanced Clinical Science and Research Group director of clinical innovation Mary Cassler said.
The study found that 40% of hepatitis C patients taking interferons — which include Genentech’s Pegasys (peginterferon alfa-2a) and Merck’s PegIntron (peginterferon alfa-2b) — were not adherent, which could put them at risk of the disease progressing, but those who were taking antidepressants as well as interferons had the highest rates of adherence, with 68.5% taking their drugs properly.