While depression is often linked with physiological factors, the larger human environment appears to contribute to and worsen existing depression. The degree to which this is true, however, and how much impact public health and safety efforts might help mitigate depression in the populace, is less certain.

A 2011 study in the American Journal of Epidemiology, “Collective Efficacy and Major Depression in Urban Neighborhoods,” looked at data from a New York City-based study that surveyed 4,000 participants at random. The demographics of the group were: 38.1% white, 27% African American, 5% Asian, 27.2% Hispanic, and 2.5% belonging to other racial groups. The researchers controlled for variables such as socioeconomic status, unemployment and major illness.

A social science term, “collective efficacy” is defined as a community’s general measure of “social cohesion and informal social control, or by related measures of social capital and social disorder.” Neighborhoods that have more social control and cohesion may diminish the number of stressful events with which residents must cope.

The study’s findings include:

• Lower neighborhood collective efficacy was associated with a higher rate of depression; residents in neighborhoods in the lowest quartile of collective efficacy had a 5.3% rate of major depression compared to a 2.5% rate among the neighborhoods with the highest collective efficacy.
• The degree of collective efficacy had the largest impact on residents 65 years of age or older. For those living in neighborhoods with high degrees of cohesion and control, the rate of major depression was estimated to be 2% for seniors. But under low collective efficacy conditions, the rate of major depression was 8.2% for seniors.
• Of those who identified their marital status as “separated,” the overall rate of major depression for participants, across all neighborhoods, was 10.2%.
• The highest rate of depression over all neighborhoods was within the 45-to-54 age group, with a 4.5% rate of major depression.
• Among those with less than a high school diploma, the major depression rate was 7.7% across all neighborhoods, making them the most susceptible group by education level.

The researchers concluded that, particularly for the elderly, “facilitation of collective action in high collective efficacy communities could improve local services and amenities, and such improvements may affect behaviors as well as mental and physical health.”

Tags: African-American, Hispanic, Latino, race, ethnicity and community, mental health, depression, residence characteristics, social environment