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Antidepressant prescribing has risen nearly 400% since 1988, according to data from the Centers for Disease Control and Prevention (CDC). More than 1 in 10 Americans over age 12 now takes an antidepressant, the study finds, and yet two-thirds of those with severe symptoms of depression do not take antidepressants at all.

The new research, led by CDC epidemiologist Laura Pratt, was based on responses from about 12,000 people who took part in a national annual health survey in 2005-08. The findings were released on Wednesday as a National Center for Health Statistics Data Brief.

The findings reflect the paradoxical reality of depression treatment in the U.S. While some observers complain that antidepressants are being handed out like candy, the data show that patterns of prescription generally adhere to what is known about depression prevalence in the U.S. In fact, the research suggests that depression is consistently undertreated.

First of all, depression is common: 9.1% of American adults will suffer from the illness at any given time, according to earlier CDC research. Although the current study finds that antidepressant prescriptions (11%) are more common than depression, earlier data show that about one-fifth of those prescriptions are written to treat conditions other than depression, such as anxiety disorders, pain and menopausal symptoms. That means the “excess” 2% of prescriptions aren’t likely to represent overprescribing. Current rates may even reflect underprescribing: the CDC study finds that only one-third of people with symptoms are taking medication.

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Further, depression is seen twice as often in women than in men. The CDC found that women were overall 2.5 times more likely to take antidepressants than men. That could mean either that women are more likely to seek help than men (which has been shown in earlier studies) or, again, that women are also being treated for anxiety and other disorders, which skew female too.

In terms of age, depression most frequently hits people between the ages of 45 and 64. And indeed, the CDC found that Americans in this age group were more likely than other age groups to receive prescription drugs to treat it. Nearly 23% of women between 40 and 59 took antidepressants in 2005-08.

Fears of overprescribing have also centered on young people — particularly given data suggesting that some of the medications can increase suicide risk among teens — but researchers found that only 2.8% of boys and 4.6% of girls ages 12 to 17 took antidepressants. According to an analysis of data from the National Household Survey on Drug Use and Health in 2005, about 9% of teens in that age group had experienced a major depressive episode in the previous year.

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Perhaps the most concerning finding in the CDC report is that people who take antidepressants are taking them long term. About 60% of people had taken the medications for two years or longer, and 14% had taken antidepressants for more than a decade. On its face, that sounds scary, but since depression can be a chronic disorder, and since research shows that maintenance on antidepressants cuts the risk of relapse in half, long-term use can be appropriate. However, as with the vast majority of medications, there is not much research on long-term effects of the drugs and, clearly, such study is needed here.

The agency did find several areas where prescribing rates failed to follow trends of depression prevalence. One involved race: although blacks and Hispanics are more likely to be depressed than whites, the data showed that antidepressants were taken by 14% of whites, compared with just 4% of blacks and 3% of Hispanics.

Moreover, although depression is much more common among the poor and unemployed, there was no difference in prescribing rates by income.

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The real story here is that depression is depressingly common in the U.S. and that depression sufferers aren’t getting adequate treatment, especially if they are young, poor or members of a minority group. The study also found that less than a third of those taking the medications had seen a mental-health professional within the past year, which means they probably get their prescriptions as their only treatment from a primary-care doctor.

But our overburdened mental-health system isn’t a sexy story — at least not compared with tales about heedless, pill-popping hedonists and the antidepressant makers who supply them.

Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland‘s Facebook page and on Twitter at @TIMEHealthland.