Anxiety and Somatic Complaints in Children with Recurrent Abdominal Pain and Anxiety Disorders

Recurrent abdominal pain (RAP) is the most common recurrent pain complaint of childhood (McGrath, 1990). The pain must occur at least once a month for at least 3 months, in order to meet traditional criteria (Apley, 1975); however, many researchers note that Apley's (1975) criteria are too general and include too many subtypes of abdominal pain, including those with an organic cause, to be a useful classification (Rasquin-Weber et al., 1999). For the purposes of this article, we will continue to use the term “RAP” to denote abdominal pain that is without organic cause (i.e., functional), is usually periumbilical and does not relate to any specific physical activity. Epidemiological studies suggest that RAP affects 8–25% of school-age children ages 9- to 12-years old (Apley, 1975; Devanarayana, de Silva, & de Silva, 2008; Huguet & Miro, 2007; Konijnenberg, de Graeff-Meeder, van der Hoeven, Klimpen, Buitelaar, & Uiterwaal, 2006), and is more prevalent among girls (Apley, 1975; Colletti, 1998). RAP accounts for 2–4% of pediatric office visits (Starfield, Katz, & Gabriel, 1984), and many children with RAP go through potentially risky and possibly unnecessary hospitalizations, tests and procedures, thus placing a heavy burden on the medical community (Walker, Garber, Van Slyke, & Greene, 1995). Medical evaluations reveal organic disease in fewer than 5% of children evaluated in primary care settings (Stickler & Murphy, 1979). Nonetheless, nearly one-third to one-half of children with RAP continue to complain of abdominal pain and related symptoms after they reach adulthood (Walker et al., 1995). RAP is defined as “functional” because, in most cases, no organic cause can be found to explain the child's pain. RAP is therefore best conceptualized using a biopsychosocial approach that examines factors other than disease as potential mechanisms through which the condition emerged or is exacerbated (Gatchel, Peng, Peters, Fuchs, & Turk, 2007). One psychological variable that may contribute significantly to RAP in children is anxiety. A recent meta-analysis shows that internalizing symptoms, as measured by parent- and self-report, are approximately six times more likely to occur in children with RAP than matched healthy controls (Dufton & Compas, 2007). Campo et al. (2004) conducted an empirical study that showed parent reports of psychological symptoms as measured by the Child Behavior Checklist (CBCL; Achenbach & Rescorla, 2002) were significantly higher for children with RAP than for a matched healthy control. In addition, four studies completed structured diagnostic interviews with this population and found the prevalence of anxiety disorders in children with RAP to be between 42% and 85% (Campo et al., 2004; Dorn et al., 2003; Garber, Zeman & Walker, 1993; Liakopoulou-Kairis et al., 2002). The association between recurrent pain and anxiety in children is important for several reasons. First, there is evidence of an association between physical and psychological problems in children and adolescents. Egger, Costello, Erkanli, and Angold (1999) found that stomachaches, headaches, and musculoskeletal pains were strongly associated with anxiety, depression, and behavioral disorders in children age 9- to 16-years old. Second, physical symptoms are often part of the criteria for a psychological disorder. For example, “repeated complaints of physical symptoms (such as headaches, stomachaches, nausea, or vomiting) when separation from major attachment figures occurs or is anticipated” is part of the definition of separation anxiety disorder as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV, American Psychiatric Association, 1994). Third, pain symptoms may exacerbate or contribute to psychological symptoms, and vice versa. For example, a child with recurrent nausea induced by her stomachaches may become anxious in situations in which she may be far from a restroom, and as a result she may refuse to leave home to attend school or other social functions. Her avoidance of social situations may, in turn, increase her anxiety when she anticipates or is forced to engage in activities outside the home, which may also then exacerbate her gastrointestinal symptoms. Temperament and responses to stress may also play an important role in the development and maintenance of the illness, as well as account for the possible link between RAP and anxiety. For example, a behaviorally inhibited temperament in infancy is predictive of anxiety disorders in childhood (Biederman et al., 1993; Hirshfeld et al., 1992), and children with RAP have been found to display many temperamental features found in behaviorally inhibited children (Campo et al., 2004). Further, differences in temperament have been associated with differences in biobehavioral reactivity to stress (Boyce, Barr, & Zeltzer, 1992). For example, behavioral inhibition has been associated with a number of psychophysiological correlates, such as a high and stable resting heart rate (Kagan, Reznick, & Snidman, 1988). Because of the strong association between behavioral inhibition and anxiety disorders, many of these psychophysiological responses to stress are also found in anxious children, adolescents, and adults (Grillon, Ameli, Merikangas, Woods, & Davis, 1993; Thayer, Friedman, & Borkovec, 1996). It is possible that children with RAP may also display these same psychophysiological correlates that may contribute to their abdominal pain. Finally, the association between RAP and anxiety disorders and symptoms needs to be examined while controlling for somatic symptoms and features of anxiety that may artificially inflate this association. If recurrent bouts of abdominal pain are one of the criteria for an anxiety disorder, the apparent association between RAP and anxiety may be a result of this overlap in symptoms. To date, only one study has specifically compared children with RAP and children with an anxiety disorder. Dorn et al. (2003) compared children meeting criteria for RAP (n = 14) with children meeting criteria for an anxiety disorder (n = 14) and matched healthy controls (n = 14) using a structured diagnostic interview as well as several questionnaires. Dorn et al. found that 64% of the children with RAP met criteria for an anxiety disorder and that the RAP and anxious participants had comparable scores on psychological measures. This study builds upon Dorn et al.'s results by assessing the level of anxiety symptoms and diagnoses in a population of children with RAP, children with anxiety and a healthy comparison group. This current builds upon Dorn et al.'s results by including a larger sample size (and increased statistical power), obtaining parents’ and adolescents’ reports of internalizing symptoms (e.g., somatic complaints, anxiety, and depression), and using different and more specific measures of anxiety symptoms. We hypothesize that children with RAP will present with significantly more symptoms of anxiety than well children, though less than the children with an anxiety disorder. In addition, we expect the overall levels of somatic complaints to be higher in the RAP group than in both the anxiety and well groups given that this is a population with recurrent functional pain. Finally, structured diagnostic interview data will be examined in order to determine the point-prevalence rate of anxiety disorders in children with RAP. We hypothesize that children with RAP will have significantly more anxiety disorder diagnoses than well children.