Commentary: To intervene or not? Appreciating or treating individual differences in childhood temperament – remarks on

In the current issue of this journal, Rapee (2013) reports that the incidence of internalizing disorders was reduced as a result of a brief parent centered intervention amongst adolescents who as young children were characterized with the temperament of behavioral inhibition (BI). The intervention was administered when children were 3 to 5 years of age and consisted of a short parent training program (i.e., six 90-min group sessions). Now, some 10 years later, those adolescents whose parents participated in the intervention were less likely to develop both anxiety and depressive disorders. The intervention appeared to be most effective for girls; fewer reductions in internalizing disorders were found for adolescent males previously characterized with BI. The data from this early prevention study are impressive in demonstrating the lasting effects of a brief targeted intervention on the emergence of internalizing disorders. Although the current study demonstrated prevention/intervention effects, the approach raises a number of issues in need of careful consideration.

First, what exactly is behavioral inhibition? In the research literature BI is thought of as a temperament identified early in infancy and not an early manifestation of a disorder. It is characterized by heightened motor and emotional reactivity to novelty. Behaviorally inhibited infants and toddlers avoid unfamiliar adults and are wary of novel objects and situations. In early childhood, these children display social reticence, not engaging in and often avoiding interaction with same age peers. Behaviorally inhibited children’s tendency to withdraw from novel or unfamiliar social situations often makes them less assertive and prone to peer rejection with its associated negative self-perceptions. Inhibited children have fewer friends and some inhibited children report greater anxiety and loneliness than others. One of the possible results of behaviorally inhibited children’s experiences during childhood may be the emergence of social anxiety disorder (Fox, Henderson, Marshall, Nichols, & Ghera, 2005). Indeed, in our work we have found that the temperament of BI is a risk factor for social anxiety, with up to a four-fold increase in the odds of a lifetime diagnosis of social anxiety disorder among adolescents with consistently high levels of BI from ages one to seven (Chronis-Tuscano et al., 2009). BI and anxiety disorders share similar behavioral and physiological characteristics, such as heightened autonomic and startle reactivity and heightened amygdala activation to threat. Despite these commonalities with anxiety, the temperament of BI is seen in approximately 15%–20% of all young children with the majority developing typical non-impaired social functioning (Fox et al., 2005).

The current report provides an opportunity to emphasize differences between the temperament of BI and symptoms associated with anxiety disorders. In an earlier report of this early intervention study, Rapee and colleagues (Rapee, Kennedy, Ingram, Edwards, & Sweeney, 2005) found that while the intervention decreased symptoms of anxiety in 3–5 year-old children undergoing treatment, it did not affect parent report of temperament. In a follow-up of this sample, Rapee, Kennedy, Ingram, Edwards, and Sweeney (2010) again found that the intervention reduced symptoms of anxiety but not temperamental inhibition 3 years after the delivery of the intervention. While the current study does not report on temperament characteristics of the adolescent sample, the earlier pattern of findings suggests that temperamental BI and anxiety symptoms are not one and the same and that exogenous or endogenous factors most likely interact with the initial temperament toward the emergence of clinical symptoms (Rapee, 2010).

A second means for understanding the differences between BI and anxiety is that not all children identified as behaviorally inhibited will develop an anxiety disorder. While BI emerges as the best known predictor of risk for later anxiety, only around 40% of behaviorally inhibited children go on to develop social anxiety disorder (Clauss & Blackford, 2012). In the current study (Rapee, 2013), about half the sample developed an anxiety disorder (47.8% of boys and 61.3% girls in the control condition; 55.6% of boys and 38.7% girls in the intervention condition), again suggesting that factors in the environment or within the child independent of temperament may play a significant role in the emergence of anxiety. In our own research, we found that parenting style moderates the relations between BI and later risk for anxiety disorders: inhibited children whose parents are over solicitous and overprotective are likely to remain inhibited and display heightened anxiety symptoms (Hane, Cheah, Rubin, & Fox, 2008). Other work from our laboratory suggests that attention bias to threat and cognitive control influence the continuity of behavioral inhibition and emergence of anxiety (Fox et al., 2005). These perturbations in attention mechanisms reflect both preferential treatment of specific categories of stimuli (i.e., bias to threat cues) and heightened vigilance of one’s own performance and behavior (i.e., error monitoring). We have suggested that overprotective parenting may in fact heighten these attention biases to threat and error monitoring thus leading to a developmental cascade of increased anxious symptoms amongst certain behaviorally inhibited children in certain families (Fox, Hane, & Pine, 2007).

Perhaps most importantly is the question as to whether prevention programs like the one described by Rapee (2013) should be uniformly applied to all children with the temperament of behavioral inhibition. On the one hand, the intervention was successful in reducing anxiety disorders, is short in duration, and appears relatively easy to administer. On the other hand, the majority of children with BI will not go on to develop anxiety disorders, and providing this intervention may end up labeling a particular child as anxious, or heightening parent worry when there is less cause for concern. There is also the issue of cost, both for the prevention program itself and the long term costs on mental health services for those not treated. Would money spent on prevention be better spent on treating children who currently are already affected but not able to receive the treatment they need? Ideally, we would have money to do both. But what if we do not? Given that about half of inhibited children will not develop anxiety, making treatment unnecessary in half of the children who would receive it, might limited funds be better spent on children who definitely need treatment? These are difficult issues to grapple with. Diversity in approaches to the environment and individual differences in the manner in which people respond to novelty are what provide interesting and multifaceted aspects to society.

Temperamental variations early in life form the foundation upon which these diversities emerge. Reflective, quiet, individuals may be as valued in a society as outgoing exuberant ones (Kagan, 1994). Parents should be provided the education to value individual differences in their young children and the information necessary to guide their children towards healthy adaptive lives. However, it may be unnecessary to implement, on a widespread basis, a prevention program for a common temperament, such as behavioral inhibition, that is associated with one type of important individual difference in approaching the world.