African-Americans and Hispanics with major depressive disorder are less likely to get antidepressants than Caucasian patients, and Medicare and Medicaid patients are less likely to get the newest generation of antidepressants.

Researchers from the University of Michigan School of Public Health examined data from 1993 to 2007 to try to understand the antidepressant prescribing patterns of physicians. They looked at two things: who received antidepressants, and what type of antidepressant was prescribed.

They found that race, payment source, physician ownership status and geographical region influenced whether physicians decided to prescribe antidepressants in the first place. Age and payment source influenced which types of antidepressants patients received.

The study found that Caucasians were 1.52 times more likely to be prescribed antidepressants than Hispanic and African-American patients being treated for major depressive disorders. However, patient race was not a factor in the physician’s choice of a specific type of antidepressant medication.

“This study confirmed previous findings that sociological factors, such as race and ethnicity, and patient health insurance status, influence physician prescribing behaviors,” said Rajesh Balkrishnan, associate professor in U-M SPH and principal investigator. “This is true in particular for major depressive disorder treatment.” Balkrishnan also has an appointment in the College of Pharmacy.

Newer antidepressants, such as SSRI’s and SNRI’s are considered the first-line pharmaceutical treatments for major depressive disorder. Older generation drugs include TCAs, MAOIs, and others, and tend to have more side-effects.

The study found that Medicare and Medicaid patients were 31 percent and 38 percent less likely to be prescribed antidepressants, respectively, compared to those with private insurance.

Geography and physician ownership status also factored into which patients received antidepressants. Sole practitioners compared to non-owners were 25 percent less likely to prescribe antidepressants, and physicians in metropolitan areas were 27 percent less likely to prescribe antidepressants in all patients with depression.

However, physicians who had seen the patients before were 1.4 times more likely to prescribe antidepressants.

Researchers also analyzed which patients received the newer antidepressants or the older antidepressants. Findings included:

-  An increase in patient age was associated with a 7 percent decreased likelihood of physicians’ prescribing only SSRI/SNRI antidepressants compared to only older antidepressants.
-  Compared to private insurance, Medicare and Medicaid patients were 58 percent and 61 percent less likely to be prescribed only newer antidepressants, respectively.
-  HMO patients had a 2.19 times higher likelihood of being prescribed only other newer antidepressants.
-  Compared to the West, physicians who practiced in the Northeast were 43 percent less likely to prescribe other newer antidepressants only, and 43 percent less likely to prescribe combined therapy for patients.

This study revealed important implications for mental health policy, Balkrishnan said.“We need policy makers to design interventions to improve physician practice guidelines adherence,” he said. “This will help eliminate unnecessary variations among physician practices and to obtain optimal health care for patients.”

Other authors on the manuscript include Hsien-ChangLin, Balkrishnan’s former doctoral student, now assistant professor of Health Policy at Indiana University, and Steven Erickson, associate professor at the U-M College of Pharmacy.

The paper, “Physician prescribing patterns of innovative antidepressants in the United States: The care of MDD Patients 1992-2007,” the article appeared online last month in the International Journal of Psychiatry in Medicine.

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The University of Michigan School of Public Health has been promoting health and preventing disease since 1941, and is ranked among the top five public health schools in the nation. Whether making new discoveries in the lab or researching and educating in the field, our faculty, students, and alumni are deployed around the globe to promote and protect our health.

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Written by Laura Bailey