American women face a greater risk of depression in states where personal income levels vary widely, according to a new study covering 50 U.S. states.

Huge income gaps in a community can make people feel impoverished, even when they are not poor by economic standards - and blaming themselves for their “failure” may add to depression risk, researchers said.

The effect was stronger for women than for men, they report in the Journal of Epidemiology and Community Health.

“Mental health has some individual components to it, but there are also powerful social forces that can act on it,” said Nancy Beauregard, from the University of Montreal in Canada, who was not involved in the research.

The current study shows that “where you live matters, unfortunately,” Beauregard told Reuters Health.

Past research has found similar trends on the local scale, but Roman Pabayo, a researcher at Harvard University’s School of Public Health in Boston, and his colleagues wanted to get a broader national picture.

The researchers analyzed data from a previous national mental health survey that included 34,653 adults. They also used a formula to calculate levels of income inequality in each state, and then divided the states into five groups, from the most equal to the least.

They found that women living in states with the broadest income ranges, like New York and the District of Columbia, are nearly twice as likely to experience depression compared to those in more equal states such as Utah and Alaska.

In states with the greatest income differences, an average of 14 percent of the population lived in poverty compared to 9 percent in the more equal states.

To rule out other personal factors that could explain a person’s depression risk, the researchers adjusted for family history of depression, poor physical health, unemployment, education, age, gender and other variables. They also looked at whether a person lived in an urban, suburban or rural environment.

After the adjustments, the link between state-level income inequality and depression remained strong for women in the study, but was not seen among men.

The drive to ‘keep up with the Joneses’ and pursue the American dream despite low-paying jobs could build up frustration and disappointment, the study authors speculate in their report.

Pabayo told Reuters Health women should demand better access to mental health services by voting or talking to local and state representatives.

Paradoxically, “during tough economic times, the response is to cut taxes for the wealthy and cut back on social programs,” he said.

On top of fraying social programs, jobs traditionally filled by women, like teaching and home care aid, generally do not get paid what they are worth to society, said Naoko Muramatsu of the University of Illinois in Chicago.

“Women are more likely than men to have jobs where even if they work harder, they cannot change the situation,” said Muramatsu, who was not part of the study.

“We need to have social policies in place to protect vulnerable populations,” she said, pointing to recent efforts by fast food workers to raise minimum wage as one example.

“It’s important to think about what society can do, and not just women,” Muramatsu added.

SOURCE: Journal of Epidemiology and Community Health, online September 24, 2013.

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Income inequality among American states and the incidence of major depression

Methods We used data from the National Epidemiologic Survey on Alcohol and Related Conditions (n=34 653). Respondents completed structured diagnostic interviews at baseline (2001–2002) and follow-up (2004–2005). Weighted multilevel modelling was used to determine if US state-level income inequality (measured by the Gini coefficient) was a significant predictor of depression at baseline and at follow-up, while controlling for individual-level and state-level covariates. We also repeated the longitudinal analyses, excluding those who had a history of depression or at baseline, in order to test whether income inequality was related to incident depression.

Results State-level inequality was associated with increased incidence of depression among women but not men. In comparison to women residing in states belonging to the lowest quintile of income inequality, women were at increased risk for depression in the second (OR=1.18, 95% CI 0.86 to 1.62), third (OR=1.22, 95% CI 0.91 to 1.62), fourth (OR=1.37, 95% CI 1.03 to 1.82) and fifth (OR=1.50, 95% CI 1.14 to 1.96) quintiles at follow-up (p

<0.05 for the linear trend).

Conclusions Living in a state with higher income inequality increases the risk for the development of depression among women.

  Roman Pabayo,
  Ichiro Kawachi,
  Stephen E Gilman

  Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts, USA
  Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
  Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, USA

  Correspondence to Dr Roman Pabayo, Department of Social and Behavioral Sciences, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; .(JavaScript must be enabled to view this email address)