Poverty marks a gene, predicting depression

http://www.eurekalert.org/pub_releases/2016-05/du-pma051916.php

Public Release: 24-May-2016
Poverty marks a gene, predicting depression
New study of high-risk teens reveals a biological pathway for depression
Duke University

A long line of research links poverty and depression. Now, a study by Duke University scientists shows how biology might underlie the depression experienced by high-risk adolescents whose families are socio-economically disadvantaged.

The study, published May 24, 2016 in the journal Molecular Psychiatry, combined genetics, brain imaging and behavioral data gathered as adolescents were followed for more than three years as part of a larger study.

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Adolescents growing up in households with lower socioeconomic status were shown to accumulate greater quantities of a chemical tag on a depression-linked gene over the course of two years. These "epigenetic" tags work by altering the activity of genes. The more chemical tags an individual had near a gene called SLC6A4, the more responsive was their amygdala -- a brain area that coordinates the body's reactions to threat -- to photographs of fearful faces as they underwent functional MRI brain scans. Participants with a more active amygdala were more likely to later report symptoms of depression.

"This is some of the first research to demonstrating that low socioeconomic status can lead to changes in the way genes are expressed, and it maps this out through brain development to the future experience of depression symptoms," said the study's first author Johnna Swartz, a Duke postdoctoral researcher in the lab of Ahmad Hariri, a Duke professor of psychology and neuroscience.

Adolescence is rarely an easy time for anyone. But growing up in a family with low socioeconomic status or SES -- a metric that incorporates parents' income and education levels -- can add chronic stressors such as family discord and chaos, and environmental risks such as poor nutrition and smoking.

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