Researchers have found that people in the lowest income brackets had higher overall rates of attempted suicide, mood and personality disorders than those with the highest income .

The findings, published today in the Archives of General Psychiatry, are consistent with previous studies that have shown a link between low income and higher rates of mental disorders. However, the direction of that link has been unclear - it's also possible that having a mental disorder means people are likely to make less money. 

Surveys wrere analysed of almost 35,000 adults in the U.S. conducted on two separate occasions that were 3 years apart. Interviewers assessed study participants for a range of mental disorders, as well as asking them about their total household income.

Among all participants, about 1 in 5 had some kind of mental disorder at the time of the second survey.

In general, lower income was linked with a higher rate of almost all mental disorders the researchers analyzed, including mood disorders, anxiety disorders, and substance abuse disorders.

People in the lowest income bracket making less than $20,000 per year were also more likely to have a personality disorder, such as borderline or antisocial personality disorder, than those in the highest income bracket, with a household income of $70,000 per year or higher.

Those with the lowest income were also more likely to have attempted suicide at some point.