Over the past 20 years, American antidepressant use has grown. Almost nine percent of the U.S. populace received at least one antidepressant prescription per month from 2005 to 2008, according to the Centers for Disease Control and Prevention, and these meds are the third most commonly prescribed class of drugs in the United States. Who’s to blame? Non-psychiatrist doctors who prescribe antidepressants even in the absence of a psychiatric diagnosis, reported a study by Baltimore’s Johns Hopkins Bloomberg School of Public Health researchers and published in Health Affairs.

For the study, researchers examined data from the 1996-2007 National Ambulatory Medical Care Surveys regarding visits to doctors’ offices by patients, ages 18 years and older.

The scientists contrasted patients who were prescribed antidepressants without a psychiatric diagnosis, those with prescriptions accompanied by psychiatric diagnoses, and also those who received neither antidepressants nor psychiatric diagnoses.

Findings showed prescription of antidepressants without an accompanying psychiatric diagnosis increased from almost 60 percent in 1996 to nearly 73 percent in 2007. That means, during that time, the number of providers willing to prescribe antidepressants without a psychiatric diagnosis climbed from 30 percent to about 55 percent.

“With non-specialists playing a growing role in the pharmacological treatment of common mental disorders, practice patterns of these providers are becoming increasingly relevant for mental health policy,” said lead author Ramin Mojtabai, MD, PhD, an associate professor with the Bloomberg School’s Department of Mental Health.

Antidepressant prescriptions were given out most often to people with less severe and more vaguely defined mental health issues, according to Mojtabai.

What’s his take on the situation? That health care providers should rethink their prescription practices and communicate better with mental health practitioners.

Click here to read about antidepressant limitations for treating less severe forms of depression.