The principal findings of the present study demonstrate the importance of examining the interdependent relationship between biological and sociocultural components of children’s pain experiences. As hypothesized, maternal NLE experienced in the previous 12 months were related to children’s laboratory pain responses, but not in the manner we predicted. Based on our prior findings16
and those of Chambers et al.,15
we expected that maternal perceptions of NLE would be associated with girls’ laboratory pain responses but not with boys.’ However, in multivariate analyses, we found that more negative perceptions of adverse life events in mothers was related to a number of increased pain responses in girls and lower
pain responses in boys, after controlling for child age, children’s NLE perceptions, and maternal somatization (see ). In girls, maternal NLE were associated with greater heat and pressure pain intensity whereas in boys, maternal NLE were related to lower
heat pain intensity and higher heat tolerance (see and ).
The present findings are somewhat at odds with previous studies in non-clinical samples which demonstrated that maternal characteristics in the form of maternal anxiety sensitivity16
and mothers’ responses to the cold pressor task were strongly related to girls’ laboratory pain responses but unrelated to boys’ pain responses 15
. On the other hand, the present findings are consistent with sex differences found elsewhere in the maternal and child stress literature. A similar interaction has been reported for boys and girls’ stress responses to maternal post traumatic stress disorder symptoms (PTSS)31
. Boys and girls displayed similar levels of stress when mothers reported low levels of PTSS. However, elevated PTSS in mothers was associated with a corresponding increase in stress symptoms in girls, and a decrease
in stress symptoms in boys. These findings and those of the current study suggest that elevated maternal stress may be associated with distinct meanings and behaviors for girls versus boys.
Notably, sex differences in the association between maternal NLE and child pain responses were only found for heat and pressure pain and not for cold pressor pain. Differences may have resulted from distinct demands of the tasks. Divergent results for varying pain tasks and parameters are commonly reported, which likely reflects different pain processing pathways 20, 32, 33
. The cold pressor task is thought to be most similar to acute clinical pain34
and may be less generalizable to every-day pain experiences. In fact, cold and heat pain tasks appear to represent markedly different genetic and environmental influences, with environmental factors accounting for greater variance in heat than cold pain, and genetic factors accounting for greater variance in cold than heat pain 35
. It is possible that the measure of maternal stress used in the present study represented an environmental influence in children’s pain, and was thus more closely related to the heat than the cold pain task. By extension, it is possible that maternal stress in the form of negative events impacts on children through social factors. Through social learning processes, girls may model their mother’s vulnerability to stress, psychological resources and coping when experiencing pain, while boys may model the wider culture’s views on acceptable male responses to stress when experiencing pain.
One explanation for sex differences in response to maternal stress involves social roles. Boys are encouraged to emulate models of independence and toughness, such that the tougher the situation, the more stoic the boy needs to be36
, in contrast to girls who are encouraged to display openness and expressive vulnerability37
. These sex differences in social roles often translate as differences in stress-related appraisal, coping and behavior. Compared to boys, girls are more likely to rate life events as negative38
, use emotion-focused coping37
and exhibit sensitivity to the stress of others39
. Within pain norms, boys are often pushed to withstand pain, while girls are free to report pain40
. In accord, we recently found in a subset of children from the present sample that higher self-reported masculinity in boys was associated with lower heat pain intensity32
. However, it should be noted that when we conducted additional analyses including masculinity scores in our present models of maternal NLE, the results did not change.
Given socialized differences in reacting to stress and pain it is perhaps unsurprising that maternal perceptions of NLE were associated with opposite responses in boys and girls in the current study. It is possible that as mothers experience stress, boys are reinforced for increasing levels of stoicism, while girls imitate and are reinforced for modeling their mother’s stress, which may generalize to displays of pain. Although the role of other family members was not tested in the present study, boys may imitate the responses of their fathers, who may respond to family stress in typically masculine ways, including displays of strength. These possibilities are speculative and require further testing including the examination of the impact of fathers’ behavior and child pain. Such efforts to examine parent-child pain relationships based on the sex of the parent as well as the sex of the child are currently underway in our laboratory.
Our findings revealed that maternal variables such as somatization and reports of NLE were more consistently related to child pain than children’s own reports of NLE. Mothers’ somatization was related to higher pressure intensity across sex suggesting that children may model maternal distress responses under certain laboratory pain conditions. Child self-appraised NLE on the other hand, were unrelated to their own responses to laboratory pain. As reviewed by Scharff41
, evidence of the influence of child-experienced NLE on pain complaints has been inconsistent. Some studies show no differences between children with chronic pain and controls in life events while others have reported adolescent patients with functional somatic complaints (e.g., chest pain, recurrent abdominal pain, limb pain) suffer more undesirable life events in the months before the onset of their symptoms. These divergent findings may be a reflection of children’s appraisal of as well as their ability to cope with stressful situations. For instance, Walker et al. 14
reported that maintenance of somatic symptoms was significantly related to life stress, but only in children with low levels of social competence.
The inconsistency of findings in relation to child reported NLE may also be due to the accuracy of child reports. The questionnaires assessing NLE asked about episodes in the last 12 months, and this time span may have proved challenging to younger children in the sample. Another possibility is that children’s laboratory pain behavior is modeled on their parent’s stress and pain behavior, with events in the child’s life playing less of a role in the child’s pain responses. Reports from mothers and children in this study revealed substantial differences in the frequency and stressfulness of life events (see ); indeed, child and maternal perceptions of negative events were unrelated in the present sample. Future work in this area might explore children’s individual differences, such as coping style and social competence as moderators or mediators in the association between parental life stress and child pain responsivity.
In interpreting the results, certain methodological considerations should be taken into account. Our results do not indicate how
maternal life events might influence children’s laboratory pain, and the notion that this process occurs through gender specific socialization is speculative. Reliance on self-report measures of NLE raises the issue that there may be recall bias in children and mothers remembering and rating NLE experienced in the previous year. In addition, it is possible that life events occurring more than 12 months prior may have substantial long-term effects. Future research should also incorporate physiological responses to pain, including facial expressions. Sex differences in children’s physiological responses to pain may reveal more about socialized pain sensitivity; we previously found that boys exhibited less autonomic arousal to laboratory pain tasks than girls20
. Further research may also examine developmental differences in children’s responses to parental stress. Our sample included a wide age-range and it is possible that the salience and influence of events differed for younger versus older children. Generalizability of our findings may be limited in that all children were healthy, mothers were highly educated, and fathers were not included in the current sample. Finally, the present study was cross-sectional and thus causality cannot be inferred.
Despite these limitations, we conclude that the relationship between children’s laboratory pain reactivity and maternal life stress deserves further consideration. Family background and stress may be of particular value in understanding clinical pediatric pain; the focus and content of intervention and prevention of pain in children may vary depending on parent, family and child characteristics. Although the current study was conducted in a non-clinical sample, our findings reinforce the idea that family variables are important in the assessment of child pain. These findings may also provide a step in understanding the distinct pain trajectories of men and women; parental reaction to pain and stress may set boys and girls along different pathways in their own experiences of pain and stress.