Acceptance commitment therapy (ACT) is a contextual behavior therapy (Hayes et al. 1999
). ACT entails acceptance and mindfulness strategies combined with a commitment to one’s valued goals. ACT’s main purpose is to improve a person’s quality of life, rather than to reduce the person’s symptomatology as is the case in traditional Cognitive behavioral therapy (CBT). ACT focuses more strongly on the context of a person’s thinking and behavior than traditional CBT (de Groot et al. 2008
). The hallmark feature of ACT and thus its most important outcome is psychological flexibility (Hayes et al. 2006
). Psychological flexibility (the opposite of psychological in
flexibility) entails pursuing important values and goals by choosing behavior in line with these values, while accepting (unpleasant) experiences (Hayes and Strosahl 2004
). This is distinct from traditional CBT, which focuses on the removal of symptoms of psychopathology. In recent years, ACT has gained much attention and has proven effective for various types of adult psychopathology (Hayes et al. 2006
), such as anxiety disorders (Swain et al. 2013
). Studies on ACT’s effectiveness in children are scarce and smaller-scaled (e.g., Heffner et al. 2002
) but generally show promising results (Coyne et al. 2011
Nevertheless, there are several aspects of ACT that make ACT a valuable intervention type to provide to children. First, it can be theorised that children can be forwarded as active change agents earlier on with ACT than with traditional CBT. That is, the cognitive element of ACT is easier for middle-aged children to grasp than the cognitive element of traditional CBT. Compared to traditional CBT where the focus is on changing
the content of cognitions, ACT stimulates clients to have an accepting attitude
towards their thoughts (Rector 2013
). For this purpose, metaphors are used extensively instead of literal instructions (Murrell et al. 2004
). Children are capable of interpreting metaphors from 7 years of age onward (Billow 1981
; McCurry and Hayes 1992
), and the use of metaphors in children is empirically supported (Heffner et al. 2003
). Changing the content of cognitions, as is done in traditional CBT, however, requires hypothetico-deductive reasoning skills (Kendall, Reber et al. 1990
; Ronen 1997
). This constitutes a form of abstract reasoning consistent with Piaget’s stage of formal operational reasoning, which children develop from 11 years of age onwards. The cognitive aspect of traditional CBT may be too difficult for middle-aged children to understand, but rather seems to suit the cognitive level of adolescents and adults. Second, prevention of psychopathology is most commonly aimed at children and ACT’s focus on improving psychological flexibility and quality of life suits preventive purposes. Indeed, Fledderus et al. (2010
) concluded that a preventive ACT intervention was successful at improving positive mental health by increasing psychological flexibility. Third, intervention and treatment types that include acceptance and mindfulness elements are generally considered highly suitable for children, and Goodman (2005
) and Kabat-Zinn (1990
) viewed children as more receptive for acceptance and mindfulness strategies than adults.
Because ACT seems a valuable intervention type for children, it is of importance to measure the efficacy of ACT in children. However, studies on psychological flexibility, ACT’s main outcome measure, in children are scarce, especially in middle-aged children (Greco et al. 2008
). Greco et al. (2005
), therefore, developed and validated a self-report questionnaire, the Avoidance and Fusion Questionnaire for Youth (AFQ-Y), to measure psychological inflexibility in children and adolescents. It taps cognitive fusion and experiential avoidance, as well as behavioral ineffectiveness. Cognitive fusion and experiential avoidance are two interrelated processes that produce psychological inflexibility. Cognitive fusion (Luoma and Hayes 2003
) has been defined as “the entanglement with the content of private events” (Greco et al. 2008
) and experiential avoidance (Hayes and Gifford 1997
) as “the unwillingness to experience certain private events and attempts to avoid, manage, alter, or otherwise control their frequency, form or situational sensitivity” (Greco et al. 2008
). Behavioral ineffectiveness can be viewed as a consequence or product of cognitive fusion and experiential avoidance. The AFQ-Y has been extensively validated in children aged 10 years and older (Greco et al. 2008
). Children are generally capable to complete self-report questionnaires from the age of 7 years onward (Beesdo et al. 2009
; Langley et al. 2002
; Myers and Winters 2002
). To date, information on the usefulness of applying the questionnaire in these younger children is lacking. However, before large scaled efficacy and effectiveness study’s on ACT with anxious children can be performed, insight into the role of psychological (in)flexibility in anxious children under the age of 11 is required.
In addition to acquiring insight into the role of psychological (in)flexibility in anxious children under the age of 11, it is of specific interest to relate psychological flexibility to child anxiety in a sample of middle-aged children. First, anxiety disorders are the most prevalent type of psychiatric disorders in children (Cartwright-Hatton et al. 2006
). Second, compared to other types of psychopathology, anxiety disorders have an early age of onset, with a median age of onset of 11 years (Kessler et al. 2005
). Third, forwarding children as active change agents in their therapy is of specific importance for child anxiety, as research shows that intervening via the child (instead of via parents) seems to lead to the most favorable outcomes when treating child anxiety (Simon et al. in preparation
; Thulin et al. 2014
). Finally, child anxiety is an important candidate for preventive interventions, not only because of its high prevalence and its early age of onset, but also because of its negative effects on the quality of life (Achenbach et al. 1995
), its high homo- and heterotypic continuity (Simon et al. 2014
), and its high societal costs (Bodden et al. 2008
). Intervening early is preferably done before the median age of onset of anxiety disorders (i.e.,11 years).
The primary goal of the current study, therefore, was to measure psychological (in)flexibility, and to examine the usefulness of the AFQ-Y in children aged 8–10 years. The second goal was to relate psychological flexibility to child anxiety. For this purpose, we performed a confirmatory factor analysis on the AFQ-Y items within a sample of children between 8 and 11 years old. If the questionnaire proves to be appropriate to measure psychological inflexibility in children between 8 and 11 years of age, this would create the possibility to measure the efficacy of ACT-based treatments in children of this age. In addition, psychological inflexibility was related to symptoms of anxiety in the children, thereby also providing insight into the construct validity of the AFQ-Y. We expected to replicate the forwarded factor structure of the AFQ-Y (Greco et al. 2008
), thus to identify the three subscales cognitive fusion, experiential avoidance and behavioral ineffectiveness, that, together, constitute psychological inflexibility. We further expected a positive relationship between psychological inflexibility and anxiety symptoms.
The current study sought to examine the usefulness and possibility of measuring psychological flexibility in middle-aged children (i.e., aged 8–11 years) and specifically investigated the relationship between psychological inflexibility (the opposite of psychological flexibility) and symptoms of anxiety in children. Psychological flexibility is the main outcome of ACT. Insight into the usefulness and possibility of measuring psychological flexibility is an important step to enable studies on the effectiveness of ACT in middle-aged children. For this purpose, we examined the factor structure and construct validity of the Avoidance and Fusion Questionnaire for Youth, a questionnaire that taps psychological inflexibility in children and adolescents.
Greco et al. (2005
) proposed a 17-item version of the AFQ-Y as well as a shortened 8-item version (AFQ-Y8). Although the 17-item version is suitable to measure psychological inflexibility, as well as the three factors that constitute psychological inflexibility (cognitive fusion, experiential avoidance and behavioral ineffectiveness) in children from age 11 years on (Greco et al. 2008
) and in adults (Fergus et al. 2011
), this appeared not to be the case for the middle-aged children that constituted our sample. In contrast to our expectation, the fit indices were neither met for the three-factor structure, nor for the one-factor structure (psychological inflexibility) of the AFQ-Y. However, all fit indices were met for the shortened version, the AFQ-Y8. The shortened version does not distinguish between cognitive fusion, experiential avoidance and behavioral ineffectivess. These findings indicate that it would not be valid to distinguish between cognitive fusion, experiential avoidance and behavioral ineffectiveness in children aged 11 years and younger, and that the AFQ-Y8 seems more suitable in this population, rather than the 17-item version of the AFQ-Y. We found comparable results for the factor structure of the AFQ-Y8 in boys and in girls, which means that the questionnaire taps psychological inflexibility equally well in boys and girls and no separate norms should be applied for boys and girls. Whereas the reliability of the AFQ-Y8 was questionable in young adolescents in the study of Greco et al. (2008
), the reliability of the AFQ-Y8 was adequate to good in the current study with middle-aged children.
Even though Greco et al. (2008
) did test the AFQ-Y in a small sample (n
= 9) of middle-aged children and adapted the questionnaire based on the input children provided, the questionnaire was not validated any further in this age group. We found that the AFQ-Y8 is likely to be more appropriate for this age group than the 17-item version. This is probably due to the complexity of the questions and the complexity of the answering categories. With regard to the complexity of the questions, capturing the concept psychological inflexibility in a questionnaire for children is a difficult task. Psychological inflexibility is an abstract concept and it requires meta-cognitive skills to answer questions like “my life won’t be good until I feel happy”. As Bond et al. (2011
) put it: “psychological flexibility is a subtle construct that can be difficult to convey in short statements that are understandable to people uninitiated in ACT”. Although 8–10 year old children are able to reflect on their own thoughts, it can be argued that adolescents can grasp the concept of psychological inflexibility easier than younger children. In line, children expressed difficulties with the answering categories, ranging from not true at all to very true on a 5-point Likert scale, whereas they did not express difficulties with the answering categories of the SCARED-71 that range from “almost never” to “often” on a 3-point Likert scale. The AFQ-Y8 simply contains 50 % less items than the AFQ-Y, and letting children complete this shorter version of the questionnaire asks less of their attention, which may positively affect the validity of the questions in this age group.
In line with our expectation, we found a positive relationship between psychological inflexibility and symptoms of anxiety in children. This is supportive for the construct validity of the questionnaire. If children are more anxious, their levels of psychological inflexibility increase and vice versa. Greco et al. (2008
) also showed a significant positive relation between psychological inflexibility and symptoms of anxiety in older children. Children with anxiety could thus profit from targeting their psychological inflexibility, which is done in ACT. Additionally, we found that children with anxiety levels within the clinical range had significantly higher scores of psychological inflexibility than children with anxiety scores within the normal range. This could be a first indication of treatment sensitivity of the measure psychological flexibility for children with anxiety. Finally, the relationship between symptoms of anxiety and psychological inflexibility was found to be the strongest for panic disorder and the lowest for social and specific phobia. Panic disorder is characterized by extreme momentary fusion with one’s panic thoughts and one’s body signs, and these symptoms generalize to various circumstances. Specific phobia, on the other hand, is usually restricted to very specific objects or situations. The contrast between these disorders could explain their different relation to psychological inflexibility.
Psychological flexibility is the hallmark feature and the main outcome of ACT. However, to date, the measure of psychological inflexibility (AFQ-Y) had not been validated in middle-aged children. This study showed that the AFQ-Y8 is suitable for measuring psychological inflexibility in middle-aged children. Being able to measure ACT’s main outcome in middle-aged children is encouraging for clinicians and scientists who are interested in measuring the effectiveness of ACT in middle-aged children. Anxiety has the earliest age of onset of all psychiatric disorders (except for developmental disorders), and this study showed a positive relation between ACT’s main outcome psychological inflexibility and anxiety in middle-aged children. ACT contains cognitive elements that require metacognitive reasoning skills, which middle-aged children master. Traditional CBT, however, contains cognitive elements that require abstract reasoning skills, which children acquire from eleven years of age onward. This makes ACT an interesting candidate for diminishing symptoms of dysfunctional child anxiety in middle-aged children.
This study was performed in a community sample. On the one hand, this yields information for scientists and clinicians who seek to diminish early forms of dysfunctional anxiety. Prevention and early intervention initiatives usually recruit children from community samples. On the other hand, the fact that this study was performed in a community population hinders the generalizability of the findings to clinical populations. Clinical cut-offs still need to be determined. Therefore, it is of importance to replicate this study in children who were referred for their anxiety to a mental health center.
We did not collect information on the possible presence of anxiety disorders, but only used a questionnaire to measure symptoms of anxiety in children. Although the SCARED-71 has been validated (Bodden et al. 2009
) and has been found to be predictive of anxiety disorders (Simon and Bögels 2009
), the use of a diagnostic measure would provide more insight into the severity and the level of dysfunction of the child’s anxiety. In addition, we did not collect any information on possible comorbid difficulties, such as depression.
In addition, we replaced the missing values by the item’s median, which can be considered as a relatively unsophisticated strategy of replacing missing items. However, there were only a few missing items (<0.3 % of the items), and we prefer using straightforward analytic procedures whenever possible. Because of the large sample size and the small number of missing items, more complex methods were unlikely to change parameter estimates appreciably.
Finally, although this is the first study to examine the usefulness of the Dutch version of the questionnaire and the validity of the international version has been thoroughly examined in earlier studies, a full evaluation of the instrument requires that the validity and reliability of the questionnaire needs to be established more thoroughly in this age group. The predictive validity of the Dutch AFQ-Y8, and its construct and discriminant validity should be measured in various populations, psychological flexibility should be related to various constructs and types of psychopathology, and the AFQ-Y8 should be assessed at multiple points in time. Additionally, we did not test the validity of the AFQ-Y8 separately, but, instead, distilled the scores on the items from the completed 17-item versions of the AFQ-Y. Future investigators are advised to examine the validity of the AFQ-Y8.