Rats—Even the Thought of Them—Can Cause Depression

A new study suggests the presence of rats in one's community can cause symptoms of depression. REUTERS/Krishnendu Halder

The presence of rats is enough to ignite feelings of repulsion in most people, and a new study finds that living among these rodents can also lead to serious and chronic feelings of sadness and anxiety. According to the study, published March 16 in the Journal of Community Psychology, the presence of these vermin can have an emotional impact as serious as experiencing threats of violence and witnessing drug sales.

For the study, researchers looked at data on 448 residents recruited from poor neighborhoods in Baltimore between March 2010 and December 2011. The data was extracted from a study on whether addressing depressive symptoms could help reduce behaviors like drug abuse and risky sex.

Of that group, half reported seeing rats on a weekly basis on their block, while 35 percent reported seeing them daily. Thirteen percent of study participants saw rats inside their home, with a small number of people (5 percent) reporting the pests have a presence almost daily in their home. Nearly 32 percent of the study participants said the animals are a sign of living in a bad neighborhood—almost all (80 percent) who felt that way had actually seen a rat outside in the streets.

"Those who live in areas where the perceived rat problem is the greatest are more pessimistic about their own ability to control rats, have less confidence in their neighbors' commitment to rat eradication and have relatively little faith that the city would act if called upon to address the rat problem," Danielle German, assistant professor at Johns Hopkins University Bloomberg School of Public Health and lead author on the study, said in a press statement.

The researchers found that people who considered rats a serious problem where they lived were 72 percent more likely to experience acute depressive symptoms than people who lived in similar neighborhoods but said rat infestation wasn't an issue.

Rats, like many other urban scourges, tend to make their home in areas that provide access to shelter and food. This typically means they lurk in underprivileged communities where sanitation services can be poor and vacant housing is plentiful.

Rats aren't the only freeloading, unwanted guests that can wreck havoc on a homeowner or renter's mental health. In 2013, the American Journal of Case Reports published a case study of a 62-year-old woman who committed suicide after contending with a bedbug infestation in his home. The woman had existing mental health problems, including bipolar disorder and a suspected personality disorder—but the tiny bloodsuckers pushed her over the edge. After waking up at 3 a.m. and finding a spot of blood on her nightgown, she wrote a suicide note and an email to her friend in which she said, "I cannot stand to live in fear of me being eaten alive.…" The next morning she jumped from her 17th floor balcony to her death.

The authors of the case report concluded that "given the recent surge in infestations, rapid action needs to be taken not only in an attempt to control and eradicate the bedbugs but also to adequately care for those infested by bedbugs."

The authors of the rat study come to a similar conclusion, suggesting that "attention is needed to appreciate and address psychosocial effect and environmental justice aspects of rat infestation in urban areas." They also say addressing a rat problem could help reduce the stress that results from other factors—such as drugs and violence—in poorer communities.