Twenty-five years ago, there were two groups of children. Some were poor, others were not. They all lived in a rural region, and their families agreed to talk every year to a team of researchers, for eight years in a row. The researchers meticulously recorded the mental health of these children.

It was a routine exercise for four years, and then an interesting thing happened.

A portion of this rural community suddenly had a significant increase in their income. A casino opened in their neighbourhood, and the casino’s operators distributed their profits to each local family every six months. Many other businesses came to that region, supporting the casino, and eventually nearly half of the families living in that locality were not poor anymore.

Moving out of poverty had an immense effect on the children. The frequency of psychiatric symptoms, which was high in the first four years, considerably dropped over the next four years.

This was so dramatic that by the fourth year, the symptom level was the same in children who moved out of poverty as in children who were never poor. It was as if some of their mental health issues were wiped away with a magic eraser! But increasing the income of families who were never poor in the first place had no effect on the frequency of psychiatric symptoms.

Income intervention specifically improved behavioural symptoms like conduct disorders but did not have much effect on emotional symptoms like anxiety.

This fascinating ‘quasi-experimental’ study is called The Great Smoky Mountains Study. It was led by Elizabeth Jane Costello of Duke University and published in 2003 in the medical journal JAMA.

Cited more than 1,200 times, it is a classical paper that argues strongly for social justice. While it is hard to argue against individual (physiological or behavioural) determinants of mental health using observations such as the one reported here, an interesting inference emerges from this.

When everyone has equal opportunities, individual differences affecting cognitive, interpersonal, and behavioural abilities play a key role in our mental health. But in the midst of social inequality, these specific individual effects on our mental health are likely to be much weaker than wider social effects.

You can read more at:
Costello EJ, Compton SN, Keeler G, et al. Relationships Between Poverty and Psychopathology: A Natural Experiment. JAMA 2003;290:2023–9.

By: Lena Palaniyappan