rats depression
People who see rats daily are more at risk of depressionGetty Images

People who live in neighbourhoods where rats are common face significant risks of depression, a study suggests. In Baltimore's deprived neighbourhoods, residents are confronted to report important public health problems, including frequent exposure to rats.

For the first time, scientists from the John Hopkins Bloomberg School of Public Health have looked at how this contact with rodents may impact on the psychological well-being of the population that has to deal with them on a daily basis.

In their study, published in the Journal Of Community Psychology, they find that these people face a heightened risk of suffering from depressive symptoms, such as sadness and anxiety. They could not explain these psychological problems by other factors, such as higher criminality rates.

50% see rodents weekly

Between 2010 and 2011, 448 residents were recruited as part of a study aimed at reducing risky behaviours linked to sex and drugs, by addressing depressive symptoms. African-Americans made up 87% of the participants, and a bit more than half of them (54%) were male.

They were surveyed about the health issues they faced every day and the state of the environment around them. Drug abuse and sexually transmitted infections were amongst their main worries, but the scientists also discovered that rats were a recurrent problem. Half of those surveyed reported seeing a rat at least once a week, and 35% almost every day.

For 32% of the participants the rodents were seen as "a real problem". Among this group, the scientists found that people were 72% more likely to experience acute symptoms of depression than those who did not see the animal as problematic or were not in regular contact with it.

"This study provides very strong evidence that rats are an under-appreciated stressor that affects how people feel about their lives in low-income neighbourhoods. The good news is it's modifiable. If we can do something to reduce the number of rats in these neighbourhoods, we can improve people's well-being", says lead study author Danielle German.

Improving residents' outlook

German believes the study should be an opportunity for local authorities to change their approach to rat population control. The rodent is usually considered a vector for disease, but not for depression. Recognising that it can also be a burden for the mental health of residents may lead to more vigorous actions to get rid of the animal from neighbourhoods.

"Eradicating rats from Baltimore City is a hard goal, but making it so no neighbourhood has to see rats every day is a goal we can strive for. It would go a long way towards improving the outlook of people who live in poor neighbourhoods", she concludes.