An economic interrogation of depression

Women of colour – particularly mothers – are especially vulnerable to depression in South Africa, and their children, in turn, are likely to become depressed too. How socio-economics affect depression and its transmission has been the focus of Dr Katherine Eyal’s research.

During 2012, the South African government made several changes to the eligibility criteria for child support grants, including increasing the maximum age of eligible children from six to 17. With the inclusion of this new demographic, Eyal, a senior lecturer at UCT’s School of Economics, set out to establish whether – and in which ways – this grant had an impact on the lives of adolescents and their caregivers.  

During her PhD, Eyal used data from the multi-year National Income Dynamics Study (NIDS) to look at, among other things, school enrolment. NIDS, implemented by the Southern Africa Labour and Development Research Unit based at UCT, is part of an intensive effort by the government to track and understand the shifting face of poverty in South Africa.
 

National Income Dynamics Study is part of an intensive effort by the government to track and understand the shifting face of poverty in South Africa.

Eyal found that more teenagers were going to school because of the child support grant. But more than this, she also examined the influence of the grant on the mental health of its recipients.

A snapshot of depression in South Africa

Largely neglected in South Africa’s policy reforms of the past two decades and still relatively understudied, mental health has remained a taboo subject. Relevant support structures and resources are sorely lacking, especially for those most in need.  

“It’s a simple question of data and priorities, really,” explains Eyal. “Mental health wasn’t part of the United Nation’s Millennium Development Goals, which means, globally, it hasn’t been prioritised in public health.”

The most recent, nationally representative mental health survey was conducted 16 years ago. This has left a huge gap in data on mental illnesses in the country.

However, when NIDS launched in 2008, it included a short module of 10 questions on mental health that has shed light on the state of depression in South Africa.
 

“Mental health wasn’t part of the United Nation’s Millennium Development Goals, which means, globally, it hasn’t been prioritised in public health.”

“The questions were worded in such a way that respondents wouldn’t necessarily realise they were being asked about mental health, which is crucial. Because there is still so much stigma around mental illness, people don’t want to talk about it,” says Eyal.

The NIDS survey revealed a depression rate of 25% among all respondents. Women of colour – specifically mothers – were shown to be the most vulnerable group with a rate of depression between 30% and 40%. Among adolescent respondents, 18% were depressed, of which most were female from low- and middle-income settings.

The transmission of depression

Given these high rates of depression among mothers and adolescents, Eyal decided to look at how a parent’s mental health may influence that of their adolescent children and whether alleviating socio-economic challenges could improve this.
 

...an adolescent’s risk of being depressed increased by 30% if their mother was depressed

She found that an adolescent’s risk of being depressed increased by 30% if their mother was depressed. While this showed that the transmission of depression from parent to child was a huge factor in adolescent mental health, it wasn’t clear whether this was due to genetic or environmental factors.

“If it’s genetic, no matter what your environment is – you could be rich – and you could still develop depression,” Eyal explains.

“If it’s environmental, you can be otherwise healthy but in a bad situation – and usually that’s a socio-economic situation – you’ll get depressed. The thing is, if it’s environmental, we can help out; if it’s genetic we can’t really,” explains Eyal.

Nature vs nurture

One of Eyal’s students, Simeme Mthembu, as part of her honour’s thesis, took on disentangling the genetic and environmental components of the transmission of depression, focusing on African mothers and their adolescent children.

Using NIDS data, Mthembu eliminated shared environmental stressors so that she could isolate the genetic components of the transmission of depression. She also controlled for past and present mental health in parents and isolated the environmental factors that affect parents and children simultaneously.
 

She found that when it comes to the intergenerational transmission of depression from African mothers to their adolescent children, the effect of nurture surpasses nature.

She found that when it comes to the intergenerational transmission of depression from African mothers to their adolescent children, the effect of nurture surpasses nature. In other words, the effect of environmental factors on the mental health of respondents far outweighed the effect of genetics.

One of the most illuminating findings from the study was that when a depressed mother was not resident in the household, the size of the maternal effect on adolescent depression decreased significantly.

“The likelihood of adolescent depression is 33% when a depressed mother is resident in the household, and in the same wave, when a mother is not resident, the likelihood decreases to approximately 9%,” Mthembu writes in her SALDRU working paper.

Halving the risk

Eyal has recently expanded on these findings, circling back to her original research on the child support grant and its effect on adolescent mental health. She discovered that in homes where the mother is depressed, receiving the child support grant halts and halves the risk of intergenerational transmission of depression.

“This doesn’t mean that the child support grant makes you less depressed, or your mom less depressed. It means that it stops transmission. It halves it.

“So, if your mom being depressed raises the probability of you being depressed by 30%, receiving the child support grant takes this risk down by half,” she explains.

More than this, however, Eyal’s and Mthembu’s research has highlighted the importance of mental health data in South Africa. With the NIDS possibly not continuing with a sixth wave, it’s crucial that alternative nationally representative, targeted surveys with a mental health component are conducted on a more regular basis. This will help to ensure that the mental health of vulnerable population groups – such as African women and their adolescent children – receive the attention they desperately need.