Across the world, 120 million people suffer from depression. The numbers are increasing but many causes are still unknown. A new study from the School of Public Health examined the disease in older adults and found that depression is linked to living in poor communities and neighborhood violence.

The study was published in journal Health & Place.

“Previous studies have revealed a link between poverty and depression, but few have focused on older adults,” says lead author and epidemiology doctoral student Spruha Joshi. “Studying the effect on older adults is important because they tend to be less mobile and more dependent on the amenities, services, and sources of social support in the neighborhoods where they live.”

Data for the study was drawn from the New York City Neighborhood and Mental Health in the Elderly Study II (NYCNAMES II), a three-year longitudinal study of approximately 1,300 New York City residents aged 65–75 years.

In addition to neighborhood poverty, Joshi’s study tested to see if factors like stressful life events, household income, social engagement, homicide rate, neighborhood physical and social disorder, walkability, and green space influenced the occurrence of depression. Symptoms for depression were identified using a survey answered by the participants.

Joshi and the other researchers found that neighborhood poverty was associated with higher levels of depressive symptoms among older adults. Neighborhood poverty was defined as the percent of households in each participant’s one-km network buffer living below the federal poverty level.

The researchers also found that about 30 percent of the relationship between neighborhood poverty and depression was explained by the existence of higher homicide rates in communities.

“This is the first study of its kind to date and what we need to do now is look at other populations in different cities to see whether we see similar findings,” says Joshi.

If they do, Joshi said it’s possible to reduce violence and improve the mental health of vulnerable populations by investing in violence prevention in high-poverty neighborhoods.

Joshi is advised by Associate Professor Toben Nelson.