depressed mothers have poorer peer relationships and less adequate social skills than teens of nondepressed control mothers (Beardslee, Schultz, and Selman, 1987; Billings and Moos, 1985; Forehand and McCombs, 1988; Hammen and Brennan, 2003).
Researchers have found significant associations between maternal depression and two psychobiological systems in children that have been found to play a role in emotion regulation and expression. The first is stress responses measured in either (a) autonomic activity (higher heart rate and lower vagal tone) or (b) stress hormonal levels (higher cortisol as an index of HPA axis activity). Field (1992) found that infants of depressed mothers have higher cortisol levels, especially following interaction with their depressed mothers (Field, 1992). Harsh parenting, which is sometimes associated with maternal depression, has also been linked to higher cortisol levels in children (Hertsgaard et al., 1995). Both findings suggest an association between children’s HPA axis functioning and the depressed mothers’ failure to provide sensitive, responsive care.
The second significant association with maternal depression is cortical activity in the prefrontal cortex and particularly the pattern of greater relative right frontal EEG asymmetries. This pattern is associated with the experience of withdrawal emotions in children and with depression in adults and adolescents (Davidson et al., 1990; Dawson, 1999; Dawson et al., 1992; Finman et al., 1989). Even 1-week-old infants of depressed mothers, as well as 1-month-old infants, showed greater relative right frontal EEG asymmetry compared with infants of nondepressed mothers, and these early EEGs are correlated with EEGs at 3 months and 3 years (Jones et al., 1997a), suggesting continuity of this effect. Dawson and colleagues saw similar patterns in 18-month-olds (Dawson et al., 1997). These patterns show remarkable stability from as early as age 1 week to age 3 years, suggesting that the early measures are reliably detecting a pattern of individual differences (Dawson et al., 1997, 2003; Jones et al., 1997a). Further, although restricted to a small sample, Dawson found support for both contextual stressors (marital discord and levels of stress) and children’s frontal brain activation mediating the association between a history of maternal depression and children’s behavior problems when the children were 3 years old.
Among possible moderators of associations between maternal depression and children’s frontal brain activation are the extent of exposure to depression in mothers, especially prenatal exposure. For example, the number of prenatal months of exposure to maternal depression marginally predicted left frontal lobe activation from EEG (Ashman and Dawson,