New research suggests that unemployment can change peoples' core personalities.

Researchers found that these personality changes include making some less conscientious, agreeable and open, which may make it difficult for them to find new jobs.

"The results challenge the idea that our personalities are 'fixed' and show that the effects of external factors such as unemployment can have large impacts on our basic personality," researcher Christopher J. Boyce, said in a statement. "This indicates that unemployment has wider psychological implications than previously thought."

For the study, Boyce and his colleagues examined samples of nearly 7,000 German adults who took a standard personality test at two points over four years, from 2006-2009. Of this group, 210 were unemployed for anywhere from one to four years during the experiment; another 251 of them were unemployed less than a year but then got jobs.

They looked at the so-called "Big Five" personality traits -- conscientiousness, neuroticism, agreeableness, extraversion and openness. They found that men experienced increased agreeableness during the first two years of unemployment, compared to men who never lost their jobs. But after two years, the agreeableness levels of the unemployed men began to diminish and, in the long run, were lower than those of the men with jobs. For women, agreeableness declined with each year of unemployment.

"In early unemployment stages, there may be incentives for individuals to behave agreeably in an effort to secure another job or placate those around them, but in later years when the situation becomes endemic, such incentives may weaken," researchers wrote.

With respect to conscientiousness, the longer men spent without jobs, the larger their reduction in this trait, which is also tied to enjoying one's income, according to the researchers. In comparison, women became more conscientious in the early and late stages of unemployment but experienced a slump in the middle of the study period. The researchers theorized that women may have regained some conscientiousness by pursuing non-work-related activities traditionally associated with their gender, such as caregiving.

Unemployed men showed steady levels of openness in their first year of joblessness, but the levels decreased the longer they were unemployed. Women, in contrast, showed sharp reductions in openness in the second and third years of unemployment but rebounded in year four, according to the study.

The study suggests that the effect of unemployment across society is more than just an economic concern -- the unemployed may be unfairly stigmatized as a result of unavoidable personality change, potentially creating a downward cycle of difficulty in the labor market.

The findings are detailed in the APA's Journal of Applied Psychology.