An estimated 9 percent of adult Americans currently meet the criteria for clinical depression, federal officials reported Thursday.
Rates of depression vary widely from state to state, ranging from a low of 4.8 percent in North Dakota to a high of 14.8 percent in Mississippi, according to researchers from the U.S. Centers for Disease Control and Prevention.
Overall, more people in the Southeast met the criteria for depression, compared with other parts of the nation, the researchers found.
"This is concerning from the perspective that depression is a very common and treatable mental disorder," said report co-author Lela McKnight-Eily, a clinical psychologist and epidemiologist at the CDC.
"When we see a high prevalence of depression there is definitely a concern, particularly when we see it concentrated in certain groups or concentrated in certain areas of the country," she added.
The clustering of depression in the Southeast may be partly due to chronic health conditions, such as obesity, heart disease, stroke and sleep problems, which are also common in the area, she said.
"In addition, there could also be differences in socioeconomic status, the presence of other mental health conditions and also access to health care and treatment," McKnight-Eily said.
The report is published in the Oct. 1 issue of the CDC's Morbidity and Mortality Weekly Report.
For the report, researchers collected data on 235,067 people in 45 states, the District of Columbia and two U.S. territories.
They found that besides state-to-state disparities, those more likely to have major depression -- the most serious kind of depression -- were women, racial and ethnic minorities, those without a high school education, people who were divorced or never married, those unemployed or unable to work, middle-aged people, and those without health insurance.
Of those experiencing another type of depression, the highest rate was found in ages 18-24.
"Depression is definitely undertreated," McKnight-Eily said. "Research has indicated that more people are seeking out treatment, but issues in terms of access to care, health insurance coverage -- particularly mental health coverage -- is an issue. Stigma is another barrier to treatment and care, and so is the availability of mental health providers."
The stigma attached to seeking help for depression keeps many from getting treatment, she noted. "People think they're weak or they have a notion that they should be able to handle it," she said.
The word "depression" is used so commonly to mean one is in a foul mood that people don't realize it's a disease, McKnight-Eily said. "It affects you psychologically and emotionally. It's not just having a bad day," she added.
Symptoms of depression include experiencing crying spells; feeling unhappy, hopeless, guilty or worthless; losing interest in normal activities; having trouble concentrating or making decisions; less interest in sex; sleep problems; and feeling unusual agitation, irritability and restlessness for more than a few weeks' time.
Eva E. Redei, the David Lawrence Stein Professor of Psychiatry in the Department of Psychiatry and Behavioral Sciences at the Feinberg School of Medicine of Northwestern University, said "there are no real surprises in the report."
Still, Redei was startled to learn that only 6.8 percent of those 65 and older were depressed. "That is not what I have seen in other statistics," she said.
Although depression is often unrecognized and undertreated, Redei said the current therapies are also not completely effective. "Current treatment possibilities are very limited," she said. "We are in the stone ages, compared to other areas of medicine."
Redei noted that current antidepressants work for only about half the patients. "We don't know enough about depression, and considering how huge the numbers are, I think it's outrageous," she said.
Depression affects more than 13 million U.S. adults each year and costs billions of dollars in treatment, loss of productivity, workers' compensation, and mortality, according to the CDC.
Moreover, depression affects quality of life and is associated with chronic medical problems, including cardiovascular disease, diabetes, obesity and unhealthy lifestyle choices, such as smoking, physical inactivity and binge drinking, the agency noted.
