MONDAY, April 4 (HealthDay News) -- People with low incomes are more likely to suffer mental illness, a new study suggests.

It also found that a decrease in income is associated with increased risk of anxiety, substance abuse and mood disorders.

Researchers analyzed data from nearly 35,000 adults aged 20 and older who took part in the U.S. National Epidemiologic Survey of Alcohol and Related Conditions. The participants were interviewed twice, three years apart.

"Participants with household income of less than $20,000 per year were at increased risk of incident mood disorders during the three-year follow-up period in comparison with those with income of $70,000 or more per year," wrote Dr. Jitender Sareen, a professor of psychiatry at the University of Manitoba in Canada, and colleagues.

Participants whose household income dropped between interviews were also at an increased risk of mood and anxiety disorders and substance abuse compared to participants whose income didn't drop.

The research did not show that poverty or a drop in income causes mental illness, only that people with low incomes are more likely to experience it than those with higher incomes.

There was also no association between a rise in income and increased or decreased risk of mental health problems.

The findings, published in the March issue of the Archives of Psychiatry, could prove important in terms of public health.

"Most important, the findings suggest that income below $20,000 per year is associated with substantial psychopathologic characteristics and that there is a need for targeted interventions to treat and prevent mental illness in this low-income sector of the population," the researchers concluded. "The findings also suggest that adults with reduction in income are at increased risk of mood and substance use disorders."

More information

The American Psychiatric Association has more about mental illness.