Introduction
Depression and anxiety disorders are among the most prevalent psychopathology in children (Kashani and Orvaschel
1990) and adults (Alonso et al.
2004; Jacobi et al.
2004; Kessler et al.
2005). Depression and anxiety aggregate in families, in other words parents’ depression and anxiety disorders constitute risk for depression and anxiety in the offspring (Beardslee et al.
2011; Beidel and Turner
1997; Turner et al.
1987). Infants born to depressed or anxious parents not only inherit a genetic vulnerability that predisposes them to depression and anxiety, but they also grow in socio-emotional environments marked by alterations in parents’ emotional expressions (Eley et al.
2015; Hettema et al.
2001; Nivard et al.
2015). Despite the significant family loading, some children with depressed/anxious parents never develop depression/anxiety. For those who do, there is a big variability in the outcomes. A developmental psychopathology perspective on the intergenerational transmission of depression and anxiety embraces the diversity in the developmental pathways to depression and anxiety (Cicchetti and Toth
1998; Dadds and Vasey
2001). Differently from previous work that addressed this diversity (Creswell and Waite
2015; Goodman and Gotlib
1999; Murray et al.
2009), the current review specifically focuses on infants’ exposure to depressed/anxious parents’ negative emotions as an early developmental pathway to the intergenerational transmission.
From a developmental psychopathology perspective, both adaptation and maladaptation arise from complex and dynamic transactions across psychological, biological, and social mechanisms operating at the intrapersonal and the interpersonal levels (Cicchetti and Dawson
2002; Sroufe
1990; Sroufe and Rutter
1984). It is therefore important to keep in mind that exposure effects that constitute the main scope of the current review are only one among many developmental mechanisms that may contribute to parent-to-child transmission of depression and anxiety. Isolated consideration of exposure effects can therefore not be sufficient to explain the observed variation in the child outcomes, or in the emergence of psychopathology in the offspring of depressed and anxious parents. Understanding how multiple transactions between infants’ exposure to parental depression and anxiety and other characteristics of the parent, the child and the environment dynamically determine the outcomes in the offspring remains essential (Goodman and Gotlib
1999; Murray et al.
2009).
The developmental models of parent-to-child transmission of depression (Goodman and Gotlib
1999) and anxiety (Murray et al.
2009) propose that children’s repeated exposure to parents’ depressed and anxious moods is a potential mechanism that contributes to risk for the development of psychopathology. Goodman and Gotlib (
1999) proposed that this mechanism consists of 5 inter-related components in the case of maternal depression. Here, we briefly summarize these components and extend them to anxiety disorders and to fathers. (1) Depression and anxiety in parents are defined by heightened duration, frequency and intensity of negative emotions, moods and behaviors (see American Psychiatric Association (APA)
2013). Depressed parents experience more flat and negative affect (sadness, irritability, anger, and guilt) in their interactions in everyday life. Anxious parents experience excessive fear, anxiety and worry either in response to certain specific situations or stimuli or in general (in the case of generalized anxiety disorder). (2) Due to their negative emotions/affect, parents with depression and/or anxiety may not be able to provide the optimal interpersonal environment for their children. (3) The lack of an optimal interpersonal environment will adversely affect children’s socio-emotional development. (4) Because of these adverse effects, children will acquire negative behaviors and moods that look like negative behaviors and moods of depressed parents. Finally, (5) acquisition of these negative behaviors and moods will put infants at risk for the development of anxiety and depression.
How do exposure effects dynamically change throughout development? Are there developmentally sensitive periods where the adverse effects of exposure to maternal depression/anxiety are especially pronounced? Is there a time in development where the offspring becomes immune to exposure to parents’ negative moods? To seek for answers to these questions, it is necessary to place exposure effects in a developmental framework. Building on the available evidence, the current study proposes that the first postnatal year constitutes a developmentally sensitive period for the effects of exposure to parental depression and anxiety.
Why is it important to specifically focus on the first year of life to discuss exposure effects in the intergenerational transmission of depression and anxiety? Higher prevalence of depression and anxiety in the postnatal years reveals that early years of parenthood may be a vulnerable period for the depression and anxiety in parents (Matthey et al.
2003; O’Hara and Swain
1996; Ross and McLean
2006). In turn, the rapid, experience-dependent development of emotional brain systems at this period seems to make infants particularly vulnerable to the effects of exposure to parental depression and anxiety (Leppänen
2011; Leppänen and Nelson
2009). Leppänen and colleagues suggest that infants’ exposure to parents’ expressions of emotion during daily parent–infant interactions plays an essential role in the neural fine-tuning of infants’ emotional brain systems in typical development (Leppänen
2011; Leppänen and Nelson
2009). Findings on face processing in typically developing infants illustrate the important role that exposure to primary caregivers’ faces may have on shaping attention in the first year of life: Because of being predominantly exposed to mothers’ faces, infants whose mothers are their primary caregivers show enhanced attention to mothers’ (vs. strangers’) neutral faces (3-to-6 months, De Haan and Nelson
1997,
1999; Montague and Walker-Andrews
2002). Infants’ exposure to mothers’ faces seems to also shape their attention to strangers’ faces: 3-month-old infants look longer to stranger faces if the gender of the stranger matches the gender of their primary caregiver (Quinn and Slater
2003; Quinn et al.
2002). Thus, exposure to parents’ faces in typical development tunes infants’ attention into the caregiving parents’ faces, ensuring enhanced processing of the most relevant and most frequently encountered stimuli in the environment.
Given this specific importance of environmental exposure for the development of emotional brain systems, Leppänen predicts that the influence of an atypical emotional environment provided by depressed and/or anxious parents in the early years would be
‘especially detrimental’ for later development of emotion processing abilities (Leppänen
2011, p. 185). In a parallel vein, Goodman and Gotlib (
1999) suggest that the time of exposure to parents’ depression and anxiety determines the strength of influence on child outcomes, with early years of life constituting the most vulnerable period.
But what are the effects of parental depression and/or anxiety in the first year of life on the offspring’s current and later functioning? Evidence on the effects of parental depression and anxiety in the postnatal year on later psychopathology in childhood and beyond has only started to accumulate. Research in this area is limited by certain methodological issues (such as reliance on mothers’ report of infants’ functioning, and lack of control for prenatal or concurrent depression). Nevertheless available evidence provides preliminary support for the idea that parents’ depression and anxiety may have prolonged effects on offsprings’ functioning and psychopathology. For example, longitudinal links were shown between mothers’ depressive symptoms in the first year and child behavioral and/or emotional problems at 2 (Avan et al.
2010), and 5 years of age (Murray et al.
1999). Evidence also shows a significant increase in the risk of overall psychopathology at the age of 11 in children of postnatally depressed mothers (Pawlby et al.
2008), and an increase in depression and anxiety diagnoses at the age of 13 (Halligan et al.
2007) and of 16 (Murray et al.
2011). Likewise, paternal depression was found to be linked to more behavioral and emotional problems in later childhood (Ramchandani et al.
2008; Ramchandani and Psychogiou
2009). Moreover, it seems that paternal depression may have effects on child outcomes that are specific and independent of mothers’ depression (Ramchandani et al.
2005). The available evidence on the effects of postnatal maternal anxiety reveals similar links to negative psychological outcomes in childhood (Glasheen et al.
2010) and adolescence (Glasheen et al.
2013), while the effects of exposure to paternal anxiety on later child outcomes remain to be investigated. Despite this preliminary evidence on a longitudinal link between parents’ depression and anxiety in the postnatal year and later functioning and psychopathology in their children, we know little about specific developmental pathways that contribute to the emergence of psychopathology in the offspring at specific stages of development. For the time being, it is difficult to delineate the separate and joint contributions of the diverse developmental pathways—including exposure to parental negative emotions and other genetic and environmental factors—to maladaptive child outcomes.
Which aspects of infants’ emotional development we should look for early dysfunction? From a developmental psychopathology perspective, failures of adaptation in certain developmental processes precede the emergence of psychopathology. These are probabilistically linked to the development and course of psychopathology (Sroufe
1990). In our current discussion on the early exposure to parental depression and/or anxiety, we focus on two aspects of infants’ emotional development, namely infants’ expressions of emotion during their early interactions with parents, and their attention to facial expressions of emotion. Alterations in emotional expressions in daily interactions and in attention to negative emotion are considered to be important indices of preverbal infants’ socio-emotional functioning, and correspond to the core domains where dysfunction occurs in childhood and adulthood forms of depression and anxiety (Leppänen
2006; Van Bockstaele et al.
2014). Therefore, these aspects may be particularly useful to consider to detect early effects of exposure and risk for psychopathology in preverbal infants.
What are the transitions and phenomena in infants’ socio-emotional development in the first year of life that are important to consider while discussing the effects of exposure to parental emotions? Two milestones in the socio-emotional domain that we address in the current discussion (Striano and Reid
2006) are the onset of dyadic parent–infant, and triadic parent–infant–object face-to-face interactions (D’Entremont et al.
1997; Messinger and Fogel
2007). Mothers’ positive affect and contingent responding to infants’ expressions of emotion in early dyadic face-to-face interactions are essential for the development of infants’ expression and regulation of emotions in the interpersonal domain in the first half year of life (Als et al.
1979; Cohn and Tronick
1987; Tronick
1989). In triadic parent–infant–object interactions that emerge at the second half of the first year, the parent and infant communicate affective states about an external object, person, situation or event in the environment (i.e., joint attention in the second half of the first year; Carpenter et al.
1998). Between 10 and 14 months, infants start to actively use adults’—most frequently parents’—emotional signals to regulate their behavioral reactions to ambiguous/novel aspects of the environment (so-called social referencing [SR]; Feinman
1982; Feinman et al.
1992). Parents’ emotional expressions in triadic parent–infant–object interactions serve as a basis for infants’ expression and regulation of emotional and behavioral reactions to novelty.
An important milestone that emerges in the transition from the first to the second half year of life in the domain of attention is the emergence of negativity bias in infants’ emotion processing (for a review see Vaish et al.
2008). Studies on behavioral and physiological correlates of infants’ attention consistently reveal that infants start to allocate more attention to negative (vs. positive) stimuli between 5 and 7 months of age (e.g., De Haan et al.
2004; Geangu et al.
2011; Hoehl et al.
2008; Kotsoni et al.
2001; Peltola et al.
2013). A bias for negative emotion was also reported in child behavior in SR situations: Infants change their reactions more strongly when the referee expresses negative as compared to positive emotions. Prioritized processing of negative emotion from parents was suggested to be functional at this period because it enhances the survival chances of crawling/walking infants who may come across potential dangers while exploring the more distant environment (Bertenthal and Campos
1990; Boyer and Bergstrom
2011; Campos et al.
2000; Leppänen
2011). However, repeated exposure to depressed and/or anxious parents’ negative emotions may at the same time influence emerging negativity bias in infants’ emotion processing, and behavior (Vaish et al.
2008). Vaish et al. (
2008) suggested that infants’ exposure to positive facial expressions earlier in the first year is necessary to skew the distribution of infants’ exposure to faces toward the positive end, to ensure that negative faces are perceived as more novel and more salient in the second half of the first year. Thus, changes in exposure to parents’ positive and negative affect in the first year may affect the distribution of infants’ overall exposure to positive and negative emotions, and later negativity bias.
In the current review, we incorporate child temperamental dispositions in the discussion of early exposure effects. Child temperamental predispositions are a biologically determined source of variation in infants’ emotional reactivity, expressions and arousal. Infants with a negative temperamental predisposition (also referred as negative reactivity in infancy or behavioral inhibition [BI] from toddlerhood onwards) are more likely to react to change or novelty in the environment with fearful, withdrawn, shy and avoidant responses than infants without such a predisposition (Fox et al.
2005; Kagan and Snidman
1999; Rothbart
2007). Children of depressed and anxious parents are more likely to be behaviorally inhibited than children of reference parents, and behaviorally inhibited children are more likely to develop depression and anxiety (Biederman et al.
1995; Bruder-Costello et al.
2007; Rosenbaum et al.
1993). Infants’ temperamental characteristics may additionally modulate the impact of early environmental adversity on current and later outcomes. Diathesis-stress (Zuckerman
1999) and vulnerability-stress (Ingram and Luxton
2005; Nigg
2006) models predict that infants with negative temperamental dispositions are more vulnerable to the effects of exposure to depression and anxiety from parents. Differential susceptibility to environmental influences hypothesis additionally stresses the buffering role of an adaptive rearing environment for infants with temperamental dispositions (Belsky et al.
2007; Belsky and Pluess
2009).
To address the continuity in exposure effects across clinical and non-clinical parent populations, the current discussion incorporates evidence on exposure to negative emotions in healthy parents without diagnosis in addition to parents diagnosed with depression and/or anxiety. In line with the multi-component model of exposure effects by Goodman and Gotlib (
1999), we review evidence on the depression and anxiety-related alterations in parents’ expressions of negative emotion in early parent–infant interactions, together with links of these alterations to infants’ emotional expressions in everyday interactions with parents and to infants’ attention to others’ emotional expressions.
1 First, we focus on the direct links between infants’ exposure to parents’ negative emotions, and infants’ facial expressions of emotion during daily dyadic face-to-face interactions with their parents. Second, we focus on triadic parent–infant–object interactions to look at the direct links between exposure to parental negative reactions and infants’ emotional and behavioral reactions to novel stimuli. Third, we address indirect effects of exposure by reviewing evidence on the associations of exposure to parents’ emotional facial expressions with infants’ attention to others’ emotional facial expressions. The review finishes with a discussion on potential links between exposure to parental depression and/or anxiety in the first postnatal year and later psychopathology in the offspring, followed by a discussion of mechanisms, future directions and clinical implications.
Discussion
The present study brought the first postnatal year into the spotlight to present an overview of little research evidence available on the links of infants’ exposure to parents’ negative emotions to infants’ emotional development, and to guide future research on parent-to-child transmission of depression and anxiety in this early, developmentally sensitive period. We focused on infants’ everyday interactions with the parents, and their attention to facial expressions as indices of child emotional development (see Table
1 for an overview of key findings). Our review shows parallels between parents’, and infants’ expressions of negative facial expressions in early interactions. That is, infants are less positive and more negative/flat when exposed to less positive and more negative/flat affect from depressed parents in face-to-face interactions (e.g.: Campbell et al.
1995; Cohn et al.
1990; Forbes et al.
2004). Similarly, when exposed to parents’ anxious reactions to novel stimuli in SR situations, infants become more avoidant of these stimuli if they are temperamentally fearful (Aktar et al.
2013; De Rosnay et al.
2006; Möller et al.
2014; Murray et al.
2008). Thus, infants’ fine-tuning into the parents’ expressions of emotion is essential for infants’ survival, development and socialization in the first year of life, whereas it may create a vulnerability for the effects of exposure to negative emotions in infants who have early temperamental dispositions, and/or parents with clinical depression and/or anxiety. It is important to note here that the limited number of studies that incorporated child temperamental dispositions provided support for diathesis-stress and vulnerability models as they revealed that temperamental anxiety dispositions enhance the influence of parental negative signals on child reactions (De Rosnay et al.
2006; Murray et al.
2008).
Table 1
An overview of the preliminary findings from the current review
Preliminary findings
|
Dyadic parent–infant interactions
|
Depression in mothers and fathers is linked to less positive and more negative/flat affect in parents and in infants |
Children of depressed mothers interact more positively with their non-depressed fathers or other familiar figures than they do with depressed mothers |
Comorbid anxiety in depressed parents is linked to a more pronounced decrease in positive affect in parents and children |
Mothers and fathers with anxiety disorders (without comorbid depression) do not differ from parents without diagnosis in their expressions of positive and negative affect |
Triadic parent–infant–object interactions
|
Daughters, but not sons, of depressed mothers are more positive and less negative than infants of non-depressed mothers |
Infants of depressed mothers are less likely to engage in toy exploration |
Social anxiety disorder in mothers and fathers is related to more expressed anxiety in parents during SR |
More expressed anxiety in fathers and mothers is related to more avoidance of novelty in children with temperamental dispositions for anxiety |
Attention to emotion
|
More exposure to sad faces from depressed mothers is indirectly linked to less attention to sad faces in infants |
More exposure to fearful faces from anxious parents is indirectly linked to less interest to high-intensity fear faces in infants |
Our review reveals distinct associations of parents’ depression versus anxiety diagnoses with parents’ and infants’ expressions of negative emotion in their interactions. Infants of depressed parents are exposed to less positive and more negative/flat affect in early interactions (Aktar et al.
2016; Campbell et al.
1995; Cohn et al.
1990). In contrast, expressions of affect in parents with anxiety disorders (without comorbid depression), and in their infants, do not seem to differ from reference parents in dyadic interactions (Aktar et al.
2016; Kaitz et al.
2010; Murray et al.
2007; Weinberg et al.
2008). Thus, the idea that mothers with anxiety disorders would expose their infants to more negative emotions was not supported in dyadic interactions. The alterations in anxious parents’ emotional expressions seem to be only visible in triadic interactions involving the specific situations that trigger anxiety on the side of the parent (Aktar et al.
2013; Murray et al.
2008).
The evidence on the links between infants’ exposure to parents’ facial expressions of emotions and their attention to emotional facial expressions showed that infants’ exposure to mothers’ positive affect is related to their attention to strangers’ positive versus negative emotions in typical development (De Haan et al.
2004). The link between more exposure to a certain emotion from the mother and less attention to others’ expressions of that emotion seems to hold across infants of mothers from community and clinical samples of parents. That is, typically developing infants who have been exposed to high levels of maternal positive affect in everyday life seem to attend less to the happy (vs. fearful) facial expressions (De Haan et al.
2004), while infants of depressed mothers who are exposed to increased levels of flat/negative faces of their mother seem to attend less to sad (vs. happy) facial expressions (Field et al.
1998,
2009; Hernandez-Reif et al.
2006; Striano et al.
2002). This is likely to be due to relatively increased familiarity/decreased novelty of sad faces for infants of depressed parents. Although it was tested with neutral expressions, the study by Jones et al. (
2013) also reveals a link between more anxiety in parents and less attention to mothers’ facial expressions. Note that this pattern is the opposite of an anxious/depressed information processing style defined by more attention to negative stimuli in parents and children with depression and anxiety (Leppänen
2006; Van Bockstaele et al. 2004). As preliminary evidence by Creswell et al. reveals in the case of parental SAD (2008, 2011), less attention to negative expressions may be an adaptive response that shields the infants from repeated exposure to parents’ negative moods in early interactions. In contrast, a subgroup of children with attention biases toward negative stimuli seem to be at risk for later anxiety disorders.
Reviewed evidence on the exposure effects in the first year of life is overall in line with the multi-component model by Goodman and Gotlib (
1999). Namely, it shows that parents with depression and anxiety express more negative/flat emotional expressions in everyday interactions with their infants. Due to experience-dependent nature of early emotional development, and parents’ heightened negative affect expressions, depression and anxiety diagnoses may make parents less than optimal social partners in early interactions. The interpersonal environment that they provide may be less than optimal for children’s emotional and social development. The evidence revealing more negative and flat affect and less attention to others’ negative emotion in infants of depressed and anxious parents reveals that this suboptimal interpersonal environment may affect infants’ emotional and social development. The direct links between parents’ and infants’ emotional expressions in everyday interactions are in line with the idea that children acquire negative and avoidant interactive styles that look like negative behaviors and moods of depressed/anxious parents. In turn, the indirect link between infants’ overall exposure to parental negative emotion and attention to others’ emotional expressions reveal a negative, rather than a positive association. In other words, when exposed to high levels of a certain emotion from the parent, infants seem to attend less to that emotion. We conclude that exposure to parents’ negative emotions does not necessarily have only adverse links to infants’ emotions’ processing, but it may also desensitize infants to others’ negative emotions, thus pushing infants’ processing toward the non-anxious, non-depressed information processing style. The links between infants’ expression and attention to emotion remain to be investigated in future multi-method longitudinal studies combining the observation of everyday interactions with the measurement of infants’ attention to emotional stimuli.
In contrast, the current review does not allow any evidence-based conclusions on the last component of the model by Goodman and Gotlib (
1999), i.e., on the links of exposure-related alterations in infants’ emotional development and the development of anxiety disorders and depression in childhood or adolescence. It remains unknown whether the increased negative/flat affect expressions in infants is a predisposition for later development of depression and anxiety. Longitudinal designs incorporating the measurement of socio-emotional development together with the diagnostic measurements that identify depression and anxiety in the offspring are needed to answer this question.
Our conclusions on the links of exposure to parental negative emotions to infants’ emotional development are only preliminary as only few studies addressed exposure effects in infancy, mostly in simple correlational and cross-sectional designs. This precludes strong conclusions on a causal longitudinal association between exposure to parental depression/anxiety in the first year and later psychological outcomes in the offspring. The available longitudinal work is limited to short-term prospective designs that, most of the time, did not directly assess clinical outcomes. Second, because the reviewed evidence is from highly educated, higher-middle SES parents and their infants in Western countries, the current conclusions have limited generalizability. Considering that parents’ emotional expressions in everyday interactions are part of socialization practices largely shaped by culture, it is crucial to consider the variation accounted for by cultural differences in infants’ emotional development (Halberstadt and Lozada
2011). Moreover, recent evidence reveals that infants’ attention to emotions and emotional expressions in everyday interactions differ as a function of SES, illustrating the importance of including SES in future studies as a potential source of individual differences (Clearfield and Jedd
2013; Tacke et al.
2015). In the next section, we put the findings in the context of intergenerational transmission by addressing potential mechanisms that may link exposure effects in infants’ emotional expressions, behavioral reactions and infants’ attention to the intergenerational transmission of depression and anxiety in infancy.
Intergenerational Transmission of a Depressive Interpersonal Style from Parents in Infancy
The findings consistently show that depressed mothers trigger a depressed interaction style characterized with less positive and more negative/flat affect from their infants in early interactions. Field and colleagues (Field
1984; Field et al.
1998) suggest that this may generalize to infants’ expression of emotion in their interactions with other adults and contribute to an overall less positive and more negative affective tone from the infant. The environmental transmission of this depressive interpersonal style from parents to infants may contribute to the intergenerational transmission of parental depression.
The association between more exposure to parents’ depressed mood and the less attention allocation to happy (vs. sad) expressions from strangers implies a different influence of exposure to parental depression on infants’ attention allocation (Field et al.
1998,
2009; Hernandez-Reif et al.
2006; Striano et al.
2002). That is, infants of depressed parents attend to others’ positive rather than sad facial expressions that they are already familiar with from their interactions with mothers. Infants of depressed parents also show more interest to mothers’ happy facial expressions (Striano et al.
2002). More attention to positive expressions may be adaptive for infants of depressed parents as this would increase infants’ chances for exposure to more positive emotions. In other words, infants’ increased attention to happy expressions in this period may be a protective mechanism that shields the infant from exposure to negative or flat emotional expressions of depressed mothers by directing their attention to mothers’ and others’ positive expressions. In turn, an interest to negative or flat expressions of the depressed mother may be an early risk in the intergenerational transmission of depression.
Mechanisms of Transmission
Field (
1984) suggested two potential mechanisms for the early transmission of a depressive interpersonal style from depressed parents to children in infancy. First, infants’ may acquire a dysphoric interaction style by mirroring parents’ expressions of emotion during dyadic face-to-face interactions. In line with this idea, positive associations were reported not only between infants’ and mothers’ expressions of specific emotions, but also between infants’ and mothers’ use of eye and brow muscles while expressing these emotions during face-to-face interactions (Malatesta and Haviland
1982). Second, the decreased positivity of depressed parents may render the dyadic interactions less arousing, exposing infants to lower than optimal levels of stimulation (Field
1984). In addition to a decrease in positive arousal specifically stemming from the decreased positivity in parents’ emotional expressions, depressed parents seem to provide overall a less stimulating environment for infants. For example, depressed mothers are less likely to tell stories to their infants, while depressed fathers are less likely to play with, and sing to their infant (Paulson et al.
2006).
Intergenerational Transmission of Anxious/Avoidant Reactivity Patterns from Parents in Infancy
The findings consistently reveal a significant effect of exposure to parental expressions of anxiety on infants’ emotional expressions/reactions to novel/ambiguous stimuli at the end of the first year (Aktar et al.
2013; De Rosnay et al.
2006; Möller et al.
2014; Murray et al.
2008). The increase in infants’ expressions of fear and behavioral avoidance toward novel/ambiguous stimuli was found to be especially more pronounced for infants with a temperamental disposition for anxiety. Thus, temperamental dispositions seem to modulate the link of exposure to parental anxiety to child avoidant reactions, and exacerbate the effects of exposure to parental anxiety.
Mechanisms of Transmission
The mechanisms explaining the links between repeated exposure to fearful/anxious expressions from parents with anxiety disorders and the resulting increase in infants’ fear/avoidance responses in infancy have been operationalized within the framework of fear acquisition models (Fisak and Grills-Taquechel
2007; Murray et al.
2009; Rachman
1977). Together with the learning experiences that involve direct confrontations with threat (i.e., classical conditioning), indirect acquisition of fear via verbal or non-verbal forms of social learning is among the major pathways for fear acquisition (Olsson and Phelps
2007; Rachman
1977). Classical conditioning and observational learning precede language (and instructional learning) in our evolutionary history and seem to rely on the same emotional brain systems (i.e., amygdala-mediated fear learning pathways, Olsson and Phelps
2007) in the brain. In line with this, vicarious learning is often conceptualized as a form of classical conditioning where fearful/anxious signals from parents serve as an unconditional stimulus, triggering fearful/anxious reactions. Following the pairing of these signals with ambiguous stimuli, the ambiguous stimuli become conditioned stimuli, evoking fearful/anxious reactions from the child (see Askew and Field
2008 for a review). Considering that anxious parents, by definition, have more frequent and intense experiences of anxiety triggered by ambiguity, parents with anxiety disorders are more likely to provide threat signals increasing the chances for associative learning of fear, leading to an increase in infants’ negative reactions. In addition to fear responses, infants’ observational learning of anxious parents’ anxious/avoidant behavioral styles via repeated exposure, and the resulting increase in infants’ overall perception of threat in the environment were suggested to contribute to the social transmission of anxiety from parents with anxiety disorders (Fisak and Grills-Taquechel
2007; Rapee
2001). Finally, anxious parents’ reinforcement of infants’ anxious/avoidant behaviors has been stressed as a form of operant conditioning. (Fisak and Grills-Taquechel
2007). Differently from reference parents who reinforce approach and exploration of novelty with their infants, parents with anxiety disorder can reinforce anxious/avoidant coping styles due to their own excessive reactions, or to previous aversive experiences in anxiety-provoking situations.
A preference for low-intensity negative expressions was reported in infants of parents with SAD (Creswell et al.
2008,
2011). Infants’ decreased attention to high-intensity negative faces in the case of maternal anxiety may be part of a protective mechanism that protects the infant from exposure to mothers’ fearful/anxious expressions by directing the attention away from negative emotions. Less exposure to high-intensity negative faces from others may help in bringing the distribution of overall exposure to positive and negative affect in infants of anxious parents closer to those of typically developing infants.
Exposure to the Other Parents’ Emotional Expression as a Moderator of Exposure to Depression and Anxiety
Exposure to mothers’ and fathers’ emotional expressions mostly happens together in development and jointly determines the distribution of infants’ overall exposure to emotions. This is why it is important to look at the joint effects of infants’ exposure to emotions from mothers and fathers. The implicit assumption that mothers are more important than fathers seems to considerably restrict our knowledge about fathers in this field of research, just like in other domains of developmental psychopathology. Evolutionary models of parenting challenge this assumption by assigning fathers a differential role in typical development, and in the development of psychopathology (Bögels and Perotti
2011; Bögels and Phares
2008). As our review of the evidence reveals, the effects of exposure to mothers’ and fathers’ exposure effects have rarely been investigated together. Considering our limited knowledge on the interplay of gender of the parents with psychopathology, in this section, we simply assume mothers’ and fathers’ influences are equivocal, and we refer to the secondary caregiver parent as ‘the other parent’.
Two important aspects that are likely to determine whether the influence of exposure to the other parents’ emotional expressions is a risk or a buffer are the other parent’s involvement in infant care and the other parent’s psychopathology, especially depression and/or anxiety. Involvement determines the extent of infants’ exposure to the parents’ expressions of emotion, while psychopathology determines the proportion of exposure to positive versus negative emotions from the other parent. Fathers’ availability and mental health appear as a moderator of exposure to mothers’ depression in the developmental model of intergenerational transmission of depression by Goodman and Gotlib (
1999). In accordance with this model, we suggest that exposure to the other parents’ emotions can become a risk factor in infancy when higher frequencies of exposure to the other parent co-occur with depression and anxiety in the other parent. Thus, when the other parent is highly involved in the infants’ care and has a depression and/or anxiety, the other parent may exacerbate the effect of depression and anxiety in one parent. Due to assortative mating, parents with depression and anxiety disorders are more likely to choose partners that do have similar types of psychopathology, resulting in significant associations between couples’ depression and anxiety diagnoses (Goodman
2004; Matthey et al.
2003), and in higher risk for psychopathology in the offspring (Merikangas et al.
1988a;
b). Psychopathology in the other parent not only contributes to a more pronounced genetic and biological risk for intergenerational anxiety, but also to more pronounced alterations in the overall distribution of infants’ exposure to parental emotions when the other parent is highly involved in care. In line with this idea, a study in a clinical sample of depressed mothers revealed that exposure to postpartum maternal depression is linked to later internalizing and externalizing problems in the offspring in the toddlerhood, only in the presence of paternal psychopathology (Dietz et al.
2009). Furthermore, a community study reported that exposure to fathers’ depression in infancy strengthens the association between early exposure to mothers’ depression in infancy and children’s behavioral problems in the kindergarten only if the father is involved in care (Mezulis et al.
2004). These findings suggest that the other parents’ depression, together with his/her involvement, may create more pronounced alterations in infants’ exposure and lead to poorer outcomes when both parents are depressed. Similarly, when both the mother and the father have anxiety, and are involved in infants’ care, a higher frequency of exposure to parental expressions of anxiety in anxiety-provoking situations would be expected to be associated with less optimal outcomes than in the case of a single parent having anxiety disorder.
Alternatively, in cases where the other parent has no diagnosis of depression or anxiety, and is involved in infant care, exposure to the other parents’ emotional expression may provide the infants the opportunity to interact more positively with the other parent on a regular basis, which may help to bring the distribution of infants’ overall exposure closer to the typically developing infants’ exposure. The findings suggesting that fathers compensate for mothers’ depression by expressing more positive affect than their depressed partners in their face-to-face interactions with the infant support this idea (Edhborg et al.
2003; Hossain et al.
1994). However, contrasting evidence revealing no significant differences in the interactions of depressed mothers and non-depressed fathers with their infants (Chabrol et al.
1996), and less optimal interactions in non-depressed fathers when the mother is depressed (Goodman
2008) show that the other parent may not always be able to compensate for partners’ depression and anxiety. Thus, the other parent’s ability to compensate may depend on several factors including their own depression and the negative influences of living with a depressed partner on fathers’ own functioning and on the marital relationship quality. Future studies focusing on the joint effect of exposure to maternal and paternal emotions should thus consider dynamic transactions between the other parents’ involvement, psychopathology, along with other factors related to the marital functioning.
Parents’ Emotion Coaching as a Potential Mechanism in the Intergenerational Transmission of Depression and Anxiety
Our review on parent and infant emotional expressions and reactions in everyday interactions illustrates the extent to what infants rely on parents’ skills to regulate their negative emotions in the first year of life. Considering this early regulatory function of parents’ emotional reactions and expressions on infants’ emotion in early interactions (also see Bornstein
2013), parent-to-offspring transmission of emotion regulation difficulties may play a role in parent-to-offspring transmission of depressed or anxious moods (Campbell-Sills and Barlow
2007). Impairments in the down-regulation of negative emotion characterize both childhood and adulthood forms of depression and anxiety disorders (Cisler et al.
2010; Joormann and Gotlib
2010). Because depressed and/or anxious parents have difficulties in down-regulating their own negative emotions, they may also be less likely to detect, accept, or acknowledge infants’ experience of negative emotions in everyday interactions. Emotion coaching is the term that refers to the extent to which parents welcome infants’ negative emotions and provide guidance for infants’ recognizing, understanding and dealing with the experience of negative emotions (Gottman et al.
1997). Higher levels of parental emotion coaching have been linked to better emotion regulation skills, better adjustment and less internalizing problems in childhood and adolescence (Gottman et al.
1996; Stocker et al.
2007). Moreover, in line with differential susceptibility to environmental influences hypothesis, recent evidence reveals that children benefit from parents’ emotion coaching especially if they have a disposition for negative emotion (Dunsmore et al.
2016). This evidence on a buffering/protective function of parental emotion coaching on child functioning in older children of non-diagnosed parents raises the question of whether better emotion coaching in depressed and/or anxious parents may alleviate some of the observed alterations in depressed/anxious parents’ emotional expressions with their infants in daily life. Considering higher rates of emotion regulation difficulties in depression and anxiety, and higher rates of negative temperamental dispositions in children of depressed/anxious parents, it is important to investigate how better parental emotion coaching skills may be related to parents’ affect during interactions, and to infants’ emotional development in early years.
The Effect of Exposure to Parental Depression and Anxiety on Infants’ Emotional Development: Future Directions
Our review on the associations between exposure to parents’ emotional expressions and infants’ emotional development in the first year of life reveals the paucity of longitudinal research that addressed the hypothesized links between exposure to maternal and paternal negative emotion, emotional development in infancy, and later psychological outcomes in the offspring. A better understanding of how environmental influences such as exposure to parents’ depression and anxiety contribute to maladaptive outcomes (alone and in interaction with other non-environmental influences) crucially depends on future longitudinal designs that will include assessment of these components from prenatal years to childhood/adolescence in the offspring of depressed/anxious (vs. control) parents.
Recent years were marked by a growing interest in understanding behavioral and neural markers of psychopathology in infancy. Several ongoing longitudinal projects are currently underway to investigate the longitudinal links between observed maternal and paternal emotional expressions/reactions in everyday situations in infancy to later outcomes in childhood (see work the social development study by Bögels and colleagues; e.g., Aktar et al.
2013,
2014; Nikolić et al.
2016) and in adulthood (see longitudinal work by Murray and colleagues on the intergenerational transmission of depression, and social anxiety (e.g., Murray et al.
2007,
2008; Prenoveau et al.
2017) years. Another ongoing project (by Pérez-Edgar and colleagues) addresses the links between infants’ temperamental negative affect, attention biases (obtained via behavioral and physiological measurements) and psychopathology in the first two years of life. The findings from these studies will shed light on the developmental pathways to psychopathology in children of depressed/anxious parents.
Based on our review, we suggest that the following specific issues should be given priority in future research. First, it is important to notice that previous investigations of exposure to parental emotion effects in daily interactions, and in infants’ attention did not include measurements of purely genetic and biological influences. It is therefore unclear to what extent the associations in parents’ and infants’ expressions of emotions and reactions to novel stimuli are explained by environmental exposure after controlling for genetic and biological vulnerabilities in the offspring of parents with depression and anxiety. The studies investigating the links between overall exposure to parents’ depression/anxiety and infants’ attention have relied on mothers’ report. Observations of parents’ negative emotions constitute a more objective index of infants’ actual exposure and therefore must be considered in future studies. Second, exposure effects have not been investigated longitudinally or cross-sectionally in the first year across the developmental transitions signaling the onset of dyadic parent–infant and triadic parent–infant–object associations. For example, we know that mothers with depression are less positive and more neutral/flat during parent–infant interactions in the first half year of life, but we do not know whether these parents also express less positive emotion during infants’ exploration of objects in triadic parent–infant–object interactions in the second half year of life. Future longitudinal investigations of the exposure effects should take into account the milestones in infants’ emotional development. The third issue concerns the associations between behavioral and physiological correlates of infants’ emotional reactivity and of attention allocation. Future research should aim at elucidating the links between infants’ emotional expressions, behavioral reactions and attention to emotion for a more complete picture of infants’ emotional development at different levels of analysis. The final issue is the inclusion of fathers. Previous evidence reviewed above on exposure effects in typically developing infants and in infants of depressed and/or anxious parents predominantly comes from mothers. For a more complete understanding of the exposure effects in the family contexts in early years, it remains essential to investigate differential and interactive effects of exposure to mothers’ and fathers’ negative moods in everyday interactions on infants’ emotional development. Inclusion of both parents is important to understand the compensating or exacerbating effect that the ‘secondary’ caregiver can have in case of a depressed and/or anxiety disordered mother.
Transactions Between Exposure Effects and Other Mechanisms in the Intergenerational Transmission of Depression and Anxiety: Future Directions
How does exposure to parental depression and anxiety in the first postnatal year interact with inherited genetic/biological predispositions, and other environmental mechanisms to determine adaptive/maladaptive outcomes in the offspring? Inherited genetic markers for depression and anxiety and innate dysfunction in early neuro-regulatory systems in the offspring of prenatally depressed and anxious parents (Goodman and Gotlib
1999) may create additional vulnerabilities, and strengthen the effect of the deviations related of exposure effects on later psychopathology. For example, both depression and anxiety disorders in mothers show high continuity between the prenatal and postnatal years, infants of depressed mothers are therefore likely to have already been exposed to mothers’ depression prenatally (Heron et al.
2004). Newborns of prenatally depressed mothers show altered biochemical/physiological responses (e.g., lower levels of dopamine, higher levels of cortisol levels, and lower vagal tone) that resemble their mothers’ responses (Field et al.
2006). The observed effects of exposure may be partially explained by these biochemical/physiological alterations. Alternatively, the link between exposure to parents’ negative emotions and later psychopathology may be stronger in children of prenatally depressed mothers due to these early vulnerabilities. Likewise, other environmental mechanisms that are at work during and after the first year of life including low marital quality/satisfaction, parenting stress, and socioeconomic disadvantages may diminish/exacerbate exposure effects.
It is therefore important to incorporate other environmental, biological and genetic mechanisms that operate in intrapersonal and interpersonal levels before, during and after infancy together with exposure to parental emotional expressions in future longitudinal studies on early intergenerational transmission of depression and anxiety disorders. Considering the diversity of outcomes in the offspring of anxious and depressed parents, parallel longitudinal measurements of other environmental and genetic factors, along with exposure effects, are crucial in delineating the effects of environmental exposure on concurrent socio-emotional development and subsequent development of depression and anxiety. Family, twin and adoption studies may provide important insights to how exposure-related vulnerabilities in infancy cross-sectionally and longitudinally interact with other genetic or environmental vulnerabilities to determine offsprings’ emotional development and psychopathology. This requires a shift from reliance on self-report measures of psychopathology to the integration of different methodologies allowing the assessment of environmental, biological and genetic mechanisms in future studies addressing intergenerational transmission of depression and anxiety.
Clinical Implications
The findings reviewed above on the links of exposure to parental depression and/or anxiety on infants’ emotional development highlight the importance of interventions targeting mood and anxiety disorders in the first year of parenthood to decrease the early risk posed by exposure to parents’ negative moods. Although interventions targeting maternal depression are efficient in decreasing parents’ experience of negative emotions (like stress), it remains unclear if they also improve the expression and regulation of negative affect in early parent–infant interactions (Forman et al.
2007). Studies testing the effects of additional interventions targeting parent–infant interactions in addition to mother’s depressive symptoms revealed promising results, although the outcomes were related to other aspects of dyadic functioning (like parental responsivity) than emotional expressions (see Poobalan et al.
2007). Thus, it remains to be investigated whether the interventions targeting expression and regulation of emotion in parent–infant dyads can reestablish the typical emotional expression patterns in early parent–infant interactions. Similarly, relationship-focused (e.g., Promoting First Relationships, Kelly et al.
2008), attachment-based (Bakermans-Kranenburg et al.
2003) and mindfulness-based (Potharst et al.
2017) approaches in early intervention have revealed promising improvements in parents’ functioning and in child behavior (e.g., responsitivity and contingency), while it remains to be tested whether they are also beneficial in the case of parental depression and/or anxiety. It is important that these interventions are compared in future RCT designs that incorporate the measurement of emotional expressions, as well as emotion regulation in diagnosed parents and their infants in the early postnatal years.