Ever since the killings at Virginia Tech last year, there has been widespread speculation about the relative incidence of mental health disorders among college students. A new study in The Archives of General Psychiatry finds that such disorders are common, and that far fewer students receive treatment than one might like. But the study -- believed to be the largest national comparison of the mental health of college students and comparably aged non-students -- finds that non-students are as likely to have mental health disorders and as unlikely to seek treatment as their peers in college.

The study is based on face-to-face interviews for the 2001-2 National Epidemiologic Survey on Alcohol and Related Conditions, which involved more than 5,000 individuals aged 19-25. Almost half of them, both in college and not, had some disorder, while only a minority in either group sought treatment.

The seven members of the research team that produced the study saw cause for both concern and optimism in their results. "The vast majority of disorders in this population can be effectively treated with evidence-based psychosocial and pharmacological approaches," the study says. "Early treatment could reduce the persistence of these disorders and their associated functional impairment, loss of productivity, and increased health care costs. As these young people represent our nation's future, urgent action is needed to increase detection and treatment of psychiatric disorders among college students and their non–college-attending peers."

The authors are all researchers at Columbia University, the National Institutes of Health, and the New York State Psychiatric Institute.

While the overall trends were similar for both groups of young people, there were some differences. The odds of alcohol use disorders were far greater for college students than for non-students. At the same time, college students were less likely than non-college students to have received treatment in the past year for conditions related to alcohol or drug use (5 percent vs. 9 percent of those with the condition).

College students are less likely than non-students to have nicotine dependence or bipolar disorder.

Here are some of the data, which cover a 12-month period.

Psychiatric Disorders, Personality Disorders and Substance Abuse in Students and Non-Students, 19-25