Depression is common and is associated with serious impairment and disability worldwide.1,2
The majority of research on depression has been conducted in high-income countries; however, there is accumulating evidence that the prevalence of depression is high among the poor and in poor countries.3–5
Extensive research over the past several decades demonstrates that women are roughly twice as likely to experience depression as men.6
This gender disparity emerges in adolescence and is most prominent during the childbearing years.7,8
Maternal depression is doubly concerning due to its effects not only on the women who suffer from it, but also because of its impact on family functioning and child development. Women are typically the primary caregivers of children; symptoms of depression such as depressed mood, irritability, disrupted sleep, low energy and hopelessness can clearly impair mothers’ capacities to nurture and interact with their children. A growing literature demonstrates that maternal depression is associated with poorer development of children cognitively and physically.9–12
Whereas there has been increasing empirical research regarding the assessment and prevention of maternal depression in high-income countries,13
greater attention to this problem is needed in low- and middle-income countries.5,14
Of the estimated 2.2 billion children in the world, 1.9 billion are growing up in developing countries with 1 billion of those in poverty.15
Multiple studies conducted in low- and middle-income countries demonstrate high rates of depression during pregnancy and during the post-partum period.16
Given the extreme demands involved in raising healthy children in contexts of severe poverty—e.g. seeking to provide adequate nutrition and shelter and prevent disease in resource-poor settings—it has been argued that maternal depression is an even greater concern in the developing world where children are particularly vulnerable to health and safety risks.3,17,18
A large body of psychological research has demonstrated that a major psycho-social risk factor for depression is exposure to stressors that cannot be adequately managed with existing resources. According to the empirically supported transactional model of stress and coping, psychological stress is viewed as mediated by the person’s assessment of the type and controllability of the stressor and the resources available to respond to the stressor.19
For mothers in low- and middle-income countries, the experiencing of economic demands without adequate economic resources would be expected to serve as a source of psychological stress. Reviews of the literature provide evidence for an association between lower socio-economic status (SES) and increased levels of psychological disorders in a range of low- and middle-income countries, with the most consistent pattern found for lower levels of education.5,18,20
Studies of the relationship between SES and maternal mental health have primarily relied on cross-sectional designs; thus, it is difficult to determine the causal direction of effects.
Can decreases in poverty help alleviate maternal depression? Recent experimental and quasi-experimental studies conducted in the USA have found mixed effects of welfare to work and housing voucher programmes on maternal mental health.21
The rapid growth of conditional cash transfer (CCT) poverty reduction programmes for extremely poor families in dozens of low- and middle-income countries since the mid-1990s provides a key context for rigorous investigation of this question. CCT programmes generally involve the government’s provision of income supplements to poor families contingent on their adherence to activities that are expected to promote healthier child development. Evaluation results of CCT programmes from Brazil, Mexico, Argentina and Nicaragua show that CCT programmes raise household consumption; increase school enrolment rates; improve health conditions in children such as anaemia and stunting and are linked with lower behavioural problems for children.22–25
Across countries, mothers typically are the beneficiaries of additional cash transfers from the government, the strategic assumption being that mothers will be more involved in child welfare.26
Thus, although the intended outcomes of these human capital investment programmes are for ‘children’, their mothers are the conduits by which these programmes are implemented.
To what extent does participating in a CCT programme improve the mental health of mothers, even though the mental or physical health of mothers is not targeted by the intervention? Although we could not identify any published, peer-reviewed papers on this question, two working papers by the World Bank reported on the experimental effects of government cash transfer programmes on maternal depression among very poor families in Ecuador and Nicaragua: in Ecuador, there were no effects for women who had received non-conditional (i.e. not contingent on any behaviours on the part of the family) income supplements for 17 months27
and the Nicaraguan study found a ‘borderline’ significant effect on maternal depression after 9 months of conditional cash transfers.28
In Ecuador and Nicaragua, the income supplement was equivalent to 10–15% of the family’s monthly income.
The present study further addresses this question regarding the effects on maternal depression of one of the largest and earliest CCT programmes in Latin America, the Oportunidades
programme implemented by the Mexican government. Oportunidades
) began in 1997 with an initial roll-out in rural areas with an extension to urban areas. By 2004, 5 million families in all 31 states of Mexico had enrolled in Oportunidades
. To provide a context for understanding the poverty levels addressed by the programme, the average hourly wage for rural Mexicans who work in agriculture is 7 pesos (roughly equivalent to US$0.09 or €0.07).29
The income supplementation provided by Oportunidades
was ~25% of household income. Mothers whose families participated in Oportunidades
received benefits only when family members complied with required activities, including pre-natal care, nutrition monitoring and supplementation, well infant care and immunization, preventive checkups and participation in educational workshops. Participation was monitored on a regular basis.30
Systematic evaluation of the Oportunidades
programme has demonstrated beneficial effects on child health, including physical growth, fewer sick days, cognitive development and behavioural problems.22,24,31
Women participating in the present study had received income supplementation for between 3.5 and 5 years; this time frame allows for more opportunity for potential effects on maternal mental health to be realized than in the prior evaluations conducted in Ecuador and Nicaragua. In addition, the 25% income supplement studied here for the Mexican programme represented a more substantial and potentially more psychologically impactful alleviation of the family’s level of extreme poverty.
Prior cross-sectional research with women participating in Oportunidades
identified perceived stress and perceived control as the strongest predictors of depressive symptoms.32
Although the improvement of maternal mental health was not an explicit focus of Oportunidades
, we believe that it is plausible and consistent with the large literature on stress and coping to hypothesize that this programme aimed at relieving poverty and improving child health could exert a non-trivial side effect on maternal depression. Oportunidades
may meaningfully reduce economic stress for women, reduce some stress related to the health problems and poor development of their children and increase their perception of control over their lives. Thus, we further expected that reductions in perceived stress and increases in perceived control might mediate the effects of participation in Oportunidades
on maternal depression. Our model for the potential mediators of programme effects is displayed in . Since inadequate social support could serve as a cause of both higher perceived stress and depression, we also include social support in our mediation model.
Diagram of mediation relationships