Introduction
Prevalence rates of behavioral and emotional problems and disorders in early childhood are similar to prevalence rates in older children [
1‐
4]. Based on the recognition of the mental health needs of young children [
5], clinical referral options are now available in many countries. Specific temperament traits, defined as constitutionally based differences in emotional reactivity and self-regulation [
6], have been found to predict behavioral (externalizing) problems and emotional (internalizing) problems in early childhood in several general population studies [
7‐
9]. Studies on links between temperament traits and internalizing and externalizing problem behavior in young clinically referred children are scarce, however. We therefore do not know to what extent these associations are similar across general populations and clinically referred populations. Therefore, this study investigated temperament traits and their associations with internalizing and externalizing problem behavior in young clinically referred children and compared the strenghts of these associations to an age and gender matched general population sample.
Temperament is largely seen as the expression of heritable characteristics as these unfold through maturation and experience [
10]. Neural networks including the prefrontal and anterior cingulate cortices develop under influence of genetic and environmental factors and play an important role in emotional reactivity but also in emotion regulation, attention, and cognitive control [
11,
12]. In young children, age three through seven, three broad temperament dimensions have been identified by Rothbart and colleagues: negative affectivity, extraversion/surgency and effortful control [
13,
14]. The first two dimensions, negative affectivity and surgency, represent the tendency of children to react with either negative or positive emotions to daily situations. Children high in negative affectivity respond more readily with fear, sadness and/or anger and frustration in situations, while children with high surgency are inclined to express laughter, impulsivity, activity and approach. The third dimension, effortful control (self-regulation), represents the ability to voluntarily regulate behavioral reactivity and attention, expressed by the inhibition of a dominant response and activation of a subdominant response [
15].
Several models have been proposed to explain the association between temperament and psychopathology [
16]. There is evidence for a spectrum model, which proposes that temperament traits and psychiatric disorders share etiological factors and vary along the same continuum with extreme levels of temperament traits considered psychopathology [
17‐
19]. There is also evidence for a vulnerability or resilience model, in which specific temperament traits predispose towards or protect against the onset of psychopathology in specific contexts [
20]. Furthermore, there are models in which temperament influences the expression of psychiatric symptoms (pathoplasty model), and vice versa, that psychopathology influences the expression of temperament (scar model) [
16,
17,
21]. These last two theoretical models imply that associations between temperament traits and psychopathology could be different in clinically referred children with emotional and behavioral problems compared to non-referred children in the general population.
In population studies, there is consistent evidence that high levels of negative affectivity and more fine-grained traits within this dimension (such as frustration, sadness, fear and low levels of soothability) predict both externalizing and internalizing problems in infancy, preschool age, and school age [
7,
22‐
25]. Low levels of effortful control and more fine-grained traits within this dimension (such as attention focusing, inhibitory control and low-intensity pleasure) were found to predict externalizing problem behavior, also when internalizing problems co-occurred [
22,
24]. Low levels as well as high levels of effortful control have been found associated with internalizing problems in general population children [
26]. High levels of impulsivity and activity level (subscales of surgency) were found to predict externalizing problems at preschool and school age, whereas shyness was associated with internalizing problems [
22,
24]. In sum, there is evidence from several general population studies that different temperament traits are associated to both internalizing and externalizing problems and there is also evidence for specific temperament traits predicting specific problem behavior. In addition, there is evidence from population studies for trait-by-trait moderation, such that negative affectivity is most strongly predicting externalizing problem behavior when effortful control is low [
24,
26].
Results from studies linking temperament to child problem behavior have given rise to preventive interventions in the general population. These interventions focus on increasing parents’ and teachers’ understanding of their child’s temperament, providing tools to deal with the child’s temperament traits and modifying children’s patterns of behavior such as increasing children’s self-regulation [
27,
28]. Clinically referred children already display problematic behavior which could, directly or indirectly, influence their temperament traits as perceived by their parents. However, in contrast to studies in general population children, there are few studies on the relation between temperament traits and internalizing and externalizing problem behavior in young clinically referred children. Also, comparison of studies and interpreting results is difficult due to differences on the definitions of temperament. In a small clinically referred sample of preschool children, high levels of negative affectivity were found to be associated with symptoms of anxiety, reflecting internalizing problems [
29], but no comparison was made with general population children.
In this study, we therefore investigated the levels of temperament traits (as defined by Rothbart et al. [
14]) and the associations between temperament and problem behavior in young children referred for mental health care. We compared this to an age and gender matched general population sample. First, we compared referred children with general population children on levels of broad temperament dimensions and fine-grained temperament traits. We expected that referred children display higher levels of negative affectivity and lower levels of effortful control (and related fine-grained traits) than general population children. Second, we examined associations between temperament traits and problem behavior. The associations between the three broad temperament dimensions, alone and in interaction, and internalizing and externalizing problems were examined in a path model in which all relations were estimated simultaneously. Possible differences in associations between clinically referred children and general population children were determined. Furthermore, we examined which fine-grained temperament traits were associated with internalizing problems and with externalizing problems in clinically referred children and whether these associations differed from those in general population children.
Discussion
This study aimed to examine broad and fine-grained temperament traits and their relation to psychopathology in young clinically referred children, compared to general population children. Regarding levels of temperament traits, results showed that referred children had significantly lower levels of effortful control than general population children, with less capacity to maintain attentional focus and less capacity to plan and suppress inappropriate response reactions. These findings add to earlier research that psychopathology in referred young children may be related to a constitutionally based impaired ability to voluntarily regulate behavior and emotions [
29]. Unexpectedly, the referred children did not significantly differ from the general population group in the tendency to react with negative emotions to daily situations, as shown by similar levels of negative affectivity. There was however a difference between the children in levels of soothability (a subscale of negative affectivity). Referred children showed less soothability than general population children. Soothability refers to the rate of recovery after distress, both spontaneously and in response to the soothing techniques parents use. Apparently, the parents of clinically referred children did not notice more intense negative emotions in their children than parents of general population children, but specifically experienced that their children lingered longer in negative emotions, and were more difficult to sooth. In previous population studies, soothability has indeed been found to negatively predict problem behavior in children [
24].
Regarding the associations between temperament traits and child problem behavior, we found similarities and differences between referred and general population children. The findings that more negative affectivity and less effortful control each were associated with more internalizing and externalizing problems with associations equal in magnitude for referred and general population children, support the spectrum model [
16]. More negative affectivity and less effortful control may well be temperament traits that vary across a continuum and in extreme levels represent psychopathology, as is proposed in other studies [
18,
19]. However, we did find a difference between the referred and general population group in the strength of the association between the broad temperament trait surgency/extraversion and externalizing problems. Also, we found a difference between the groups in the relation between the fine-grained temperament trait impulsivity (subscale of surgency) and externalizing problem behavior. The parents of referred children who rated their child as expressing more surgency, and specifically more impulsivity, reported more externalizing problem behavior, whereas this association was not found in the general population group. Possibly, this relation is altered in clinically referred children by a moderating factor such as parenting and/or parent–child interaction [
10]. Parents of referred children might react differently than parents of general population children when their children act impulsively, resulting in a stronger association which can add to the risk of developing externalizing problem behavior. Indeed, according to the vulnerability model, specific temperament traits may predispose towards the onset of psychopathology in specific contexts [
20]. It is also possible that psychopathology changes the expression of temperament as suggested by the scar model [
21] or that parents perceive certain temperament traits of children referred with problem behavior differently than parents of children without problem behavior.
When addressing the relations between fine-grained temperament traits and internalizing and externalizing problem behavior in referred children, several patterns emerged. Within the temperament dimension of surgency/extraversion, there were specific traits (more shyness, less smiling/laughter) related to internalizing problem behavior and other specific traits (more activity and impulsivity) related to externalizing problem behavior. These findings were expected as the traits represent internally focused behavior (i.e., shyness and smiling/laughter) and externally focused behavior (activity and impulsivity). Subscales of negative affectivity and effortful control, namely more anger/frustration, less soothability, and less inhibitory control, were found to be related to clinical levels of comorbid internalizing and externalizing problem behavior. Notably, less soothability was the only trait that was related to more internalizing and externalizing problems when viewed seperately, and also to (sub)clinical levels of comorbid internalizing and externalizing problem behavior. Therefore, soothability might be an important temperament factor in relation to general psychopathology.
Several limitations of this study must be addressed. First, as in most studies investigating young children, only parent reports were used. Although it has been suggested that shared method variance accounts for the association between questionnaire-based assessment of temperament and problem behavior [
37], there is also evidence that measurement confound does not account for the association between these constructs as reported by parents at preschool age [
8]. Temperament traits have been found to be related to child psychopathology in population studies, even after correction for possible item overlap in questionnaire measures used to assess temperament and child problem behavior [
8,
38]. Second, this study used a cross sectional design and therefore no directional or causal conclusions can be drawn. Third, while this study did account for the possible influence of gender, age and ethnicity, we did not investigate other possible relevant factors that might influence the association between temperament and psychopathology. While we did study moderation between temperament traits, previous studies have also shown that temperament traits can function as moderators in the relations between parenting/parental psychopathology and child psychopathology [
39]. Strength of this study is that the subscales of broad temperament dimensions were included to find specific relevant fine-grained temperament traits in association with problem behavior, which has often been neglected in previous research [
9,
24,
40]. The results of this study show that it is important in research on temperament and psychopathology to focus on fine-grained traits within the broad temperament dimensions. In further research, fine-grained temperament traits in referred children could also be investigated in relation to other specific problem behavior, such as social and attachment problems and outcome of treatment.
Despite the limitations, the main results of this study are in accordance with earlier research and provide implications for early assessment and treatment in young children referred for emotional- and behavioral problems. Self-regulation, including inhibitory control, has already been addressed as an important factor in temperament-based prevention intervention in children [
28] and in treatment programs for children with externalizing disorders. The results of this study support this and further suggests that impulsivity is a specifically important temperamental factor in relation to externalizing problems in clinically referred children. When specific temperament traits of children, such as impulsivity or shyness, are recognized by parents and other caregivers, both caregivers and child can learn how to deal with the traits and reduce potential negative consequences. Furthermore, the results of this study suggest that it could also be important to address soothability, the ability to calm down after distress, in diagnostic and treatment interventions of both internalizing and externalizing problems and disorders in referred children. It can be addressed in parent (caregiver)-child treatment, since young children are still dependent on their primary caregivers to help them learn to regulate their emotions and behavior.
Summary
In the current study, temperament traits and psychopathology were assessed in 216 young clinically referred children. Furthermore, on the same measures, a subset of 115 clinically referred children was compared to 115 age and gender matched children from the general population. Results showed that more negative affectivity and less effortful control may well be temperament traits that vary across a continuum and in extreme levels represent psychopathology in young children. Results also showed that temperamental impulsivity within surgency was more strongly related to externalizing problems in clinically referred children compared to children from the general population, suggesting a vulnerability or a scar effect. Results further suggest that various fine-grained temperament traits are specifically related to internalizing problems and externalizing problems. Meanwhile, soothability was found to be related to both domains of problems and could therefore be a factor related to general psychopathology. We propose that assessment of temperament in clinically referred children may be of help when customizing diagnostic procedures and tailoring treatment interventions in early childhood.