Depression is one of the most common mental health disorders but it has become even more common during a mother’s childbearing years. There is a strong association between maternal depression and child outcomes as early as birth and throughout later developmental periods. Maternal depression has been shown to contribute to multiple early child developmental problems which include impaired cognitive, social and academic functioning. Whereas children of non-depressed mothers have shown no negative outcomes in their cognitive development. Although there is an association between PPD and children’s cognitive development there is no absolute certainty that one causes the other. The purpose of this literature review is to evaluate research from various studies done on PPD and child outcomes to determine if mother’s mental health after birth is crucial for children’s cognitive development.
Smith-Nielsen, Tharner, Krogh, and Vaever (2010) conducted a longitudinal research study to determine the correlation between PPD mothers and the risk for unfavorable long-term infant developmental outcomes. 28 postpartum depressed mothers (PPD group) and 55 comparison mothers without psychopathology (nonclinical group) were selected to participate in this study. This was a sample of highly educated and first time mothers. Mothers who showed no symptoms of a mental disorder after birth were followed for 13 months through observation including their child. PPD mothers were recruited 2 months post-partum in order to screen for symptoms of depressions using Edinburgh Postpartum Depression Scale by a public health care nurse during routine home visits.
At baseline, both groups were examined for psychological and personality disorders and mental retardation through clinical interviews. Mothers who scored within the clinical range of the Edinburgh Postpartum Depression Scale when screened for postpartum depressive symptoms six to nine weeks postpartum were excluded from the study. The development of infants was also assessed at 4 and 13 months. (Smith-Nielsen et al., 2016 a).
This study determined that there was an association between PPD and poorer cognitive development for four month old infants. Infants at four months of age with currently depressed mothers had lower scores in the cognitive scale, such as low activity levels not only in maternal interaction but with unfamiliar people as well. They were also reported being less responsive to faces and voices and showed distinct patterns of social withdrawal compared to infants of non-depressed mothers ( Smith-Nielsen et al., 2016). These results show that long term effects on infants with PPD mothers only occurs if the problem is persistent since cognitive developmental scores were reported being higher with age when PPD symptoms are no longer present (Smith-Nielsen et al., 2016).
A similar study was conducted by Murray, Arteche, Fearon, Halligan, Croudace and Cooper (2010) in order to understand the association between early cognitive difficulties in children of postnatally depressed mothers and persistence throughout development. Participants for this study were 61 mothers identified with postnatal depression and 42 non-depressed mothers who were randomly selected from the same population with the majority of families in both groups being upper middle class. Mothers were assessed if they had only given birth once, were between the ages of 18–42 years, were cohabiting or married, and had healthy, full-term infants. Researchers collected data through age appropriate assessments to measure cognitive development in children at ages 1 1/2, 5, 8 and finally 16 years old where academic performance was measured (Murray et al., 2010).
For maternal measures mental state was taken into consideration through collection of psychiatric diagnostic criteria and symptom rating scales at 2 months postpartum, 18 months and 5 years. At 8, 13 and 16 years a structured clinical interview was administered to assess mental disorders. Cognitive support and enrichment were other measures used to identify if parenting had an effect on a child’s IQ at 5 and 8 years through observation of mother-child interactions with videotapes. This study determined that only boys of postnatal depressed mothers had lower secondary education exam scores compared to those of control children which was due to the ongoing negative effects of PND on maternal interactions through childhood (Murray et al., 2010).
Another study by (Der Waerden et al., 2016) was conducted on the influence persistent maternal depressive symptoms has on children’s IQ. One thousand thirty-nine mother–child pairs from the French EDEN mother–child birth cohort were followed from 24 to 28 weeks of pregnancy onwards. Participants were excluded if they had more than one pregnancy, a known history of diabetes, the inability to speak and read French or had plans to move out of the study region in the following 3 years.
Researchers used the same scale as the previously mentioned studies which was the Edinburgh Postnatal Depression Scale (EPDS) to measure maternal symptoms of depression during the first year after the child’s birth (4, 8, and 12 months postpartum). Other methods used to collect data were through sociodemographic and biomedical data on the mother and child from medical records, in face to face interviews with the mother, and by mother’s self-completed questionnaires during pregnancy and after birth (4, 8, 12, 24 months, 3, 4, and 5 years), (Waerden et al., 2016). In this study I also found similar results to the previously mentioned studies where the continuing exposure of maternal depression is more crucial than timing for children’s cognitive development. For children of mothers who had higher levels of postpartum depression there was a decrease in IQ compared to children with non-depressed mothers and also a stronger association in boys than in girls.
Other studies have looked at the effects of postpartum depression on social development such as the longitudinal study performed by Wu, Selig, Roberts, and Steele (2011) where they demonstrate that during early childhood there is a long-term association between postpartum depression and children’ social skills. In this study there was a total of 1,364 mothers of mixed ethnicity of whom 705 were boys and 659 were girls. The average age for mother’s was 28 years old (Wu et al., 2011).
In order to measure for maternal depression the Center for Epidemiological Studies Depression Scale was given to mothers in their homes or at a child care setting for children throughout different life stages between 1-3 years old. Using the scale just mentioned, mothers were asked to rate how often they experienced depression symptoms in the last week. Their scores indicated further assessment for depressive symptoms was needed. To measure children’s social skills the Social Skills Rating System was used. This system assessed children’s problem behaviors and social skills and focused on skills specific to social interactions, such as the ability to make friends or ability to control one’s temper when arguing with others.The SSRS was given to mothers in the lab or at home when children were 4 and 6 years old. Teachers completed the SSRS in school when children were 6.0 years old (Wu et al., 2011). The results showed that symptoms of maternal depression declined at a faster rate only during the initial period rather than over time. Also, exposure of high depression symptoms in mothers to infants at 1 month old reported lower social skills for older children, these results confirm previous findings where postpartum depression during early childhood is critical as it can predict poor social outcomes for children. (Wu et al., 2011).
The last study reviewed was conducted by Kurstjens and Wolke (2001) where they examined the effects maternal depression has on children’s intellectual development. During the first seven years of life children were assessed in three different occasions. In South Bavaria, Germany a sample of 8421 children (7505 being at-risk children and 916 healthy born children) and their mothers were followed since birth and assessed several times until the 5th year of the children’s life (Kurstjens & Wolke, 2001). When children were 6 years of age an interview was conducted on mothers for maternal physical and mental health by trained clinical psychologists, who were all unaware of the premature baby’s risk status.
Depressive symptoms were screened from the SADS and psychiatric history was assessed from a well-validated instrument. Timing, recency, severity, number, and duration were distinguished features of maternal depression that were assessed.The children were assessed for general development using the Griffiths Scales of Babies’ Abilities at 20 months, the Columbia Mental Maturity Scales (CMM) at 4 and 8 years for cognitive development and the Kaufman Assessment Battery for Children (K-ABC) at 3 and 6 years for intellectual development. From the results postnatal depression had no negative effects on the development of children during the first 7 years of life except for boys who were at risk of chronically depressed mothers (Kurstjens and Wolke, 2001).
From reviewing five articles on children’s exposure to postpartum depression it has been found that there is a correlation between maternal depression and impaired cognitive, social and academic performance. These studies indicate that long term effects in children are only present if persistence of PPD occurs and are more prevalent in boys due to them being more vulnerable of PPD exposure.
Limitations of these Studies
Limitations for most of these studies were small sample sizes, socioeconomic disadvantages and unhealthy behaviors as well as not finding evidence for a specific timing effect of maternal depression in the postnatal period which could have lead them to be assigned to a group with persistent symptoms and affected result outcomes. Another limitation was not having available observations on children’s social skills over time and not controlling for pre-existing depressive symptoms. This is another limitation because it is one of the major predictors of postpartum depression.
Conclusion and Future Study
Although there have been numerous studies that have shown a correlation between postpartum depression and children’s cognitive development we cannot conclude that PPD causes low cognitive scores in infants. Through investigation on this topic it has not shown that PPD has long term effects on children’s cognitive development it has only been found that when children’s low cognitive assessments scores are present it is due to the persistence of PPD symptoms.