Depressive symptoms might be transmitted from mother to child through early interactions

A study of mothers and their infants found that mothers with depressive symptoms tend to display fewer supportive responses to their infants’ positive emotions. In turn, infants who receive fewer supportive responses are more likely to exhibit depressive symptoms during toddlerhood. The paper was published in Development and Psychopathology.

Depressive symptoms refer to a range of emotional, cognitive, and physical experiences associated with depression. Emotionally, individuals may feel persistent sadness, hopelessness, or emptiness, often accompanied by a loss of interest or pleasure in activities they once enjoyed. Cognitively, depression can lead to difficulty concentrating, making decisions, or remembering details, along with feelings of worthlessness or excessive guilt. Physical symptoms include fatigue, changes in appetite or weight, sleep disturbances (insomnia or oversleeping), and unexplained aches or pains. The severity and duration of these symptoms can vary, but they typically interfere with daily functioning and quality of life.

Studies have established that depressive symptoms are often transmitted intergenerationally (between generations), particularly between mothers and their children. These studies demonstrate that children exposed to maternal depressive symptoms in the first year of life are more likely to develop internalizing symptoms (e.g., anxiety, depression, social withdrawal) between the ages of 2 and 19. However, the precise mechanisms underlying this transmission remained unclear.

Study author Gabrielle Schmitt and her colleagues sought to investigate how depressive symptoms are transmitted from mothers to toddlers. They hypothesized that mothers with elevated depressive symptoms in the first year after childbirth would display fewer supportive responses to their infants’ positive emotions. Consequently, infants receiving less support for their positive emotions would exhibit more depressive symptoms in toddlerhood.

The study involved 128 mothers and their infants, recruited through various means from Toronto, Canada, as part of a larger longitudinal study on early childhood development. Mothers were required to be proficient in English, at least 18 years old, and without major medical conditions. Infants needed to weigh more than 2,500 grams at birth.

Data were collected at three time points: in early infancy (when infants were around 6–7 months old), late infancy (around 12 months old), and toddlerhood (around 20 months old). By the third data collection point, 90 mother-child pairs (70%) remained in the study. Data collection involved Qualtrics online surveys. Mothers completed assessments of their own depressive symptoms using the Edinburgh Postnatal Depression Scale at the first and second time points and of their toddlers’ depressive symptoms using the Child Behavior Checklist for Ages 1½–5 at the third time point.

Additionally, researchers visited participants’ homes to video record mothers interacting with their infants for 30 minutes. Mothers were given a standardized set of toys and instructed to interact with their infants as they normally would. These interactions were divided into three 10-minute episodes: the first involved free interaction, the second involved the use of toys, and the third involved interaction without toys. Study authors used these videos to assess infants’ manifestations of positive emotions and mothers’ responses to those emotions.

Results showed that 22% of the mothers exhibited clinical levels of postpartum depression. On average, mothers displayed twice as many supportive responses as non-supportive responses to their infants’ positive emotions. Mothers’ responses did not vary based on the infant’s sex.

Overall, mothers with elevated postpartum depressive symptoms tended to display fewer supportive responses to their infants’ positive emotions. In turn, infants who received fewer supportive responses exhibited more depressive symptoms in toddlerhood.

The study authors tested a statistical model suggesting that the number of supportive responses an infant receives mediates the link between mothers’ and toddlers’ depressive symptoms. Results supported the possibility of such a relationship.

“Findings suggest that maternal socialization of infant positive affect is an important mechanism in the intergenerational transmission of depressive symptoms. These results emphasize the need for preventative interventions early in development,” the study authors concluded.

The study sheds light on the potential mechanism behind the transgenerational transmission of depression. However, it is important to note that both toddlers’ and mothers’ depressive symptoms were reported by the mothers themselves, leaving room for reporting bias that may have influenced the results.

The paper, “Intergenerational transmission of depressive symptoms: Maternal socialization of infant positive affect as a mediator,” was authored by Gabrielle Schmitt, Brittany Jamieson, Danielle Lim, and Leslie Atkinson.