Unemployment significantly affects the mental health of adults, especially those who do not have jobs for 27 weeks or more. Based on a new study, the longer Americans are unemployed, the higher the risk of depression. The Bureau of Labor Statistics calls this period "long-term unemployed."

Based on a survey, one in five Americans who are out of work for a year or more are depressed. This is nearly double the rate of those who are unemployed for only five weeks or less.

Gallup, an American consulting company famous for its public opinion polls, surveyed 356,599 Americans and 18,322 unemployed adults in 2013. 5.6 percent of those who have full-time jobs were depressed or receiving treatment for depression. The rate of depressed unemployed adults is 12.4 percent, almost twice the rate of depressed employed adults. People who were "long-term unemployed" are almost thrice as likely to become depressed compared to people who have jobs.

"It's not a surprise, but it's still something of a hidden problem," career coach and job recruiter Kathryn Lorenzen from Kansas City said. "Isolation is the enemy here. When someone is unemployed for a long time, they tend to lose touch with people. They withdraw from scheduled activities. And the longer they go without structured activities, the easier it is to slip into depression."

Previous studies showed that half of participants reported "embarrassment and shame" that resulted to being isolated from friends and family. Gallup asked the participants if they had laughed or smiled the day before the survey. 82.5 percent of all participants said they laughed or smiled a lot the day prior. 81.1 percent of those who were out of job for six months or less said they laughed or smiled the previous day. However, only 70.7 percent of long-term unemployed adults said they laughed or smiled the day before.

Previous studies also said that unemployed people who attend networking events and job clubs do a better job in avoiding depression. Gallup said that almost one-third of long-term unemployed people said that they socialize with friends or family less than two hours per day. This is in comparison with a quarter of all Americans.

Psychologists have always linked unemployment with different psychological ailments such as low self-esteem, anxiety and depression. It could be that unemployment causes depression or that being depressed could make it more difficult to be hired.