Intimate Partner Violence and Depression Symptom Severity among South African Women during Pregnancy and Postpartum: Population-Based Prospective Cohort Study

Abstract

Background

Violence against women by intimate partners remains unacceptably common worldwide. The evidence base for the assumed psychological impacts of intimate partner violence (IPV) is derived primarily from studies conducted in high-income countries. A recently published systematic review identified 13 studies linking IPV to incident depression, none of which were conducted in sub-Saharan Africa. To address this gap in the literature, we analyzed longitudinal data collected during the course of a 3-y cluster-randomized trial with the aim of estimating the association between IPV and depression symptom severity.

Methods and Findings

We conducted a secondary analysis of population-based, longitudinal data collected from 1,238 pregnant women during a 3-y cluster-randomized trial of a home visiting intervention in Cape Town, South Africa. Surveys were conducted at baseline, 6 mo, 18 mo, and 36 mo (85% retention). The primary explanatory variable of interest was exposure to four types of physical IPV in the past year. Depression symptom severity was measured using the Xhosa version of the ten-item Edinburgh Postnatal Depression Scale. In a pooled cross-sectional multivariable regression model adjusting for potentially confounding time-fixed and time-varying covariates, lagged IPV intensity had a statistically significant association with depression symptom severity (regression coefficient b = 1.04; 95% CI, 0.61–1.47), with estimates from a quantile regression model showing greater adverse impacts at the upper end of the conditional depression distribution. Fitting a fixed effects regression model accounting for all time-invariant confounding (e.g., history of childhood sexual abuse) yielded similar findings (b = 1.54; 95% CI, 1.13–1.96). The magnitudes of the coefficients indicated that a one–standard-deviation increase in IPV intensity was associated with a 12.3% relative increase in depression symptom severity over the same time period. The most important limitations of our study include exposure assessment that lacked measurement of sexual violence, which could have caused us to underestimate the severity of exposure; the extended latency period in the lagged analysis, which could have caused us to underestimate the strength of the association; and outcome assessment that was limited to the use of a screening instrument for depression symptom severity.

Conclusions

In this secondary analysis of data from a population-based, 3-y cluster-randomized controlled trial, IPV had a statistically significant association with depression symptom severity. The estimated associations were relatively large in magnitude, consistent with findings from high-income countries, and robust to potential confounding by time-invariant factors. Intensive health sector responses to reduce IPV and improve women’s mental health should be explored.

Abstract

In a population-based prospective cohort study, Alexander C. Tsai and colleagues examine bidirectional associations between intimate partner violence and depressed mood among pregnant and postpartum women living near Cape Town, South Africa.

Editors' Summary

Background

Violence against women perpetrated by an intimate partner is a common and widespread problem. Rates of intimate partner violence (IPV, also called domestic violence) vary widely between countries but, globally, nearly a third of women experience IPV at some time in their life. IPV is defined as physical, sexual, or emotional violence that is perpetrated on an individual by a current or former partner or spouse. Physical violence includes slapping, pushing or shoving, hitting with a fist or another object, and threatening or attacking a partner with a weapon; sexual violence means forcing a partner to take part in a sex act when the partner does not give consent; and emotional violence includes threatening a partner by, for example, preventing them seeing their family. The adverse effects of IPV against women include physical injury and sexual and reproductive health problems such as HIV infection and unwanted pregnancies.

Why Was This Study Done?

Studies undertaken in high-income countries have also shown an association between IPV and adverse mental health outcomes among women, such as depression (long-lasting and overwhelming feelings of sadness and hopelessness) and suicidal behavior. However, few if any studies on the association between IPV and depression have been conducted in sub-Saharan Africa, where the rates of IPV against women are among the highest in the world. In this population-based prospective cohort study, the researchers analyze longitudinal data collected during a cluster-randomized trial that involved more than 1,200 women living in townships near Cape Town, South Africa. The primary aim of this randomized trial was to investigate whether regular visits by “mentor mothers” (women who had successfully raised children in the face of adversity) improved maternal and child health in the 3 y following the child’s birth. As part of this trial, the researchers collected data at multiple time points (longitudinal data) on women’s experiences of IPV and symptoms of depression. Here, the researchers conduct a secondary analysis of these data to estimate the association between IPV severity and depression symptom severity among women during and following pregnancy.

What Did the Researchers Do and Find?

During the cluster-randomized trial, the researchers asked the women about their exposure to physical IPV during the past year in surveys undertaken at baseline, 6 mo, 18 mo, and 36 mo. Depression symptom severity was also measured in the women at these time points using a version of the ten-item Edinburgh Postnatal Depression Scale in the local language Xhosa; this scale is an instrument that screens for postnatal depression by asking questions about depressive symptoms experienced during the past seven days by women who have recently had a baby, such as how often they have felt sad or miserable. Statistical analyses of these data indicated that, after allowing for other factors that might affect depression symptom severity, IPV intensity had a statistically significant association (an association unlikely to have arisen by chance) with depression symptom severity. That is, an increase in IPV severity among the study participants was associated with an increase in depression symptom severity over the same period. Notably, this association was bidirectional. That is, depression symptom severity also had a statistically significant association with IPV intensity.

What Do These Findings Mean?

These findings show that, among women living in poor neighborhoods in Cape Town who have recently had a baby, IPV severity had a statistically significant association with depression symptom severity. The magnitude of this association was relatively large and consistent with findings from high-income countries. The accuracy of these findings may be limited by certain aspects of this study. For example, because the study participants were not asked about sexual violence, the severity of IPV exposure may be underestimated. Nevertheless, these findings—in particular, the demonstration that the association between IPV and depression is bilateral—have important policy and programmatic implications for women’s health in sub-Saharan Africa. Specifically, because IPV and depression may be intertwined in a vicious cycle, with IPV increasing the risk of future depression and depression increasing the risk of future victimization, multi-component interventions that combine a broad-based package of services (for example, provision of legal aid, transitional housing, and childcare support) with interventions designed to treat depression (for example cognitive-behavioral therapy) may be needed to reduce IPV and improve women’s mental health.

Additional Information

This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001943.

• A PLOS Medicine Research Article by Devries et al. reviews the evidence from high-income countries for an association between IPV and depression

• The World Health Organization provides detailed information on intimate partner violence and on depression (some information in several languages)

• The UK National Health Service Choices website provides information about intimate partner violence, including some personal stories, and detailed information about depression

• The US Centers for Disease Control and Prevention provides information about intimate partner violence and links to further resources

• The US National Domestic Violence Hotline provides confidential help and support to people experiencing IPV; its website includes personal stories of IPV

• The US National Institute of Mental Health provides information on all aspects of depression

• MedlinePlus provides links to other resources about domestic violence and about depression (in English and Spanish)

• More information about the "mentor mother" trial is available