What Makes You Blue?

Gender, income and more may affect the balance of good and bad days

Everyone has bad days -- days when you feel sad or depressed, perhaps for no specific reason.

But not everyone has the same number of these days, and research indicates that your gender, income, education and age have something to do with it.

"This is the first study that looked at this measure of depression," lead researcher Rosemarie Kobau, a public health analyst at the National Center for Chronic Disease Prevention and Health Promotion, told HealthDay .

"Mood disorders are a major public health problem in the U.S. ," she said. "They impose a substantial burden of disability and impaired quality of life." But, she added, "feeling sad, blue or depressed three days a month as a result of a stressful life situation is perfectly normal."

Depending on how depression is measured, about 11 percent of Americans have depressive disorders, Kobau said.

She and her colleagues studied 166,000 responses to the question: "During the past 30 days, for about how many days have you felt sad, blue, or depressed?" They found that young adults (those between 18 and 24) reported the highest number of days during which they experienced depressive symptoms.

However, being active keeps the blues away, according to the study. People who exercised had 1.3 fewer days with depressive symptoms during the preceding month than did sedentary people, the study found.

Researchers found that women had these feelings an average of 3.5 days a month; men had them 2.4 days.

The study also found that having money and being educated helped keep people's spirits up. College graduates and people with incomes of more than $50,000 had two sad, blue or depressed days a month, compared with almost five days for people without a high school education, and 6.1 days for people with yearly incomes of less than $15,000.

People unable to work had the most depressed days -- an average of 10.2 days a month.

Researchers also found that people who had more blue days also engaged in unhealthy behaviors such as cigarette smoking, binge drinking and not using seat belts.

"Most of those unhealthful behaviors are among the leading risk factors for disease and death in the U.S. ," Kobau said.

And when people are depressed or lose interest in things that they enjoy for more than about two weeks a month, that signals a serious problem, she said, and people should talk to their doctors about treatment.

"This is a significant study which answers some important questions and raises new ones," Dr. Ian A. Cook, an associate professor of psychiatry from the University of California, Los Angeles Neuropsychiatric Institute, told HealthDay .

While earlier work has shown that people with major depression have more disability, less quality of life and increased mortality, the study expanded what is known about less severe levels of depression -- called subsyndromal depression -- and sadness, Cook said.