The way one thinks while under depression is contagious, finds a group of scientists from University of Notre Dame, according to a report from Science Daily.

We've heard of diseases being contagious, but did you know that even depression and the way you think under this condition can also "rub off" on peers, roommates and family members. Psychological scientists Gerald Haeffel and Jennifer Hames from the University of Notre Dame conducted a study and found this to be true. According to the study findings, when a person is under depression, the way he or she thinks, rubs off on their peers and roommates, who also show signs and symptoms of depression six months later.

Authors of the study found that people who are pessimistic about events that shape out negatively, saying they couldn't do anything to alter the factors affecting the event, are more vulnerable to depression. This state is known as "cognitive vulnerability" and can be used to predict whether a person will fall into depression in the future even if he or she has never experienced depression in the past.

Generally this "cognitive vulnerability" is known to solidify during adolescence and remains constant throughout adulthood and is different for different people. However Haeffel and Hames stated that even in adulthood, this "cognitive vulnerability" can be flexible.

"Our findings suggest that it may be possible to use an individual's social environment as part of the intervention process, either as a supplement to existing cognitive interventions or possibly as a stand-alone intervention," they write. "Surrounding a person with others who exhibit an adaptive cognitive style should help to facilitate cognitive change in therapy."

The authors say that their study aims at making people aware that they should reconsider how they think about cognitive vulnerability.

"Our study demonstrates that cognitive vulnerability has the potential to wax and wane over time depending on the social context," say Haeffel and Hames. "This means that cognitive vulnerability should be thought of as plastic rather than immutable."