Most adults with depression in the United States are not receiving treatment for the disorder, according to new research published Monday in the journal JAMA International Medicine.

The study also found, however, that most American adults who are receiving treatment for depression — particularly antidepressants — do not actually screen positive for it.

In other words, large numbers of Americans are being either undertreated or overtreated for depression.

About 15.7 million adults in the U.S. have at least one major depressive episode in a given year, according to the National Institute of Mental Health. Earlier this year, the U.S. Preventive Services Task Force recommended that all adults be screened for depression as part of their routine medical care.

As background information in the new study points out, anti-depressants are not generally recommended for patients with mild or less severe depression because studies have shown they are no more effective than a placebo in such cases.  Other interventions, especially talk therapy (psychotherapy or psychological counseling) and lifestyle changes (regular exercise and stress reduction), have been found to be more helpful for this group of patients. 

Yet, antidepressant prescriptions have risen substantially in recent years, becoming the most commonly prescribed class of medication in the U.S. 

This new study appears to add weight to concerns that antidepressants are being inappropriately prescribed.

Self-reported details

For the study, a team of researchers led by Dr. Mark Olfson, a psychiatrist at Columbia University, analyzed data collected from a nationally representative sample of more than 46,000 people who participated in the Medical Expenditure Panels Survey in 2012 and 2013. The survey included a short screening questionnaire that assesses possible symptoms of depression within the previous two weeks. Participants were also asked if they had been treated for any mental-health conditions within the past 12 months and, if so, what that treatment had been and what kind of health professional had prescribed it.

The analysis showed that 8.4 percent of the survey’s participants appeared from their answers to have depression. Yet only 28.7 percent of the people who screened positive for depression had received any treatment.

On the other hand, among the survey’s participants who were receiving treatment for depression, only 29.9 percent actually screened positive for the disorder on the questionnaire, and an even smaller percentage of that group — 21.8 percent — had serious psychological distress.

Furthermore, people with mild symptoms of depression were more likely than those with serious distress to have been prescribed antidepressants.

“The clinical reasons for this pattern are unclear,” write Olfson and his colleagues, “but may include a tendency to overestimate the effectiveness of antidepressants in treating mild depression, insufficient time to provide alternative interventions for mild depression, and errors in clinical assessment.” 

Other findings

Most people in the survey who were treated for depression received that treatment from a general medical professional (73.3 percent). People were much less likely to be under the care of a psychiatrist (23.6 percent) or other mental health specialist (12.6 percent).

Interestingly, people being treated exclusively by general medical professionals for their depression were less likely to screen positive for depression or serious psychological distress. Yet, they were more likely to be taking antidepressants — and less likely to be receiving psychotherapy.

Here are some other findings from the study:

• People in the lowest income bracket were five times more likely to screen positive for depression than those in the highest income bracket. Screen-positive depression was also more likely among individuals who were separated, divorced or widowed, and who had less than a high school education.
• People who screened positive for depression were more likely to be receiving treatment if they were aged 35 to 64, female, white, non-Hispanic, had health insurance, and had completed high school.
• Antidepressants were the most common treatment for depression ((87 percent), followed by psychotherapy (23.2 percent), anti-anxiety medications (13.5 percent), antipsychotics (7 percent) and mood stabilizers (5.1 percent).
• Among people with serious psychological distress, young adults (aged 18 to 34) were four times more likely to receive a combination of anti-depressant drugs and psychotherapy than older adults (aged 65 and older). In addition, people with college degrees were almost twice as likely to receive both therapies as those with only a high school degree.

Challenges persist

The study has several limitations. Most notably, the data that was analyzed came from people’s own reports about their use of mental-health services. Such self-reports can be unreliable. Also, although scores based on the short questionnaire used in this study to screen for depression have been found to correlate with several psychiatric disorders, the questionnaire is not considered, on its own, a diagnostic tool.

Still, the study helps update our knowledge about how we’re doing at getting help to people with depression.

And, as the findings suggest, we’re doing a poor job of it.

“With the increase in antidepressant use over the last several years, it may come as a surprise to learn that widespread challenges persist in accessing depression care,” said Olfson in a released statement.”

“There are also challenges in connecting depressed patients to the appropriate level of care,” he added.

FMI: The study can be downloaded and read in full on the JAMA Internal Medicine website.