This study is a meta-analytic review of the behavioral adjustment of children and adolescents with asthma. Of 78 studies initially reviewed, 26 studies (encompassing 28 data sets), reflecting data on nearly 5000 children with asthma (mean age = 8.4 years; 40% female), met criteria for inclusion. Effect size estimates were calculated across studies using standard methods. Separate effect sizes were calculated for internalizing and externalizing behavioral problems, degrees of asthma severity, and differences in control group used (i.e., sample controls or normative data). Results indicate that children with asthma have more behavioral difficulties than do healthy children, with the effect for internalizing behaviors being greater than that for externalizing behaviors (dmn = .73 vs .40). Increased asthma severity was associated with greater behavioral difficulties. Results did not differ by comparison group (healthy controls vs normative data). The findings suggest that patients with asthma, particularly children with severe asthma, should be considered at higher risk for behavioral difficulties that may necessitate psychosocial intervention.
Asthma is currently the most common childhood chronic illness and affects more than 6% of children in the United States.1 The prevalence of pediatric asthma has increased dramatically over the past two decades. In children ages 5 to 14 years, asthma increased 74% between 1980 and 1994. In children up to 4 years old, asthma prevalence increased approximately 160% over this period of time. Increased asthma prevalence has been associated with considerable health care use and functional morbidity. For example, the rate of emergency department visits for asthma increased approximately 17% between 1992 and 1995.1 In addition, asthma accounts for over 10 million school absences a year.2 In sum, asthma has become an increasingly common clinical problem in pediatrics, with the potential for significant morbidity.
The relationships between disease factors, psychosocial variables, and functional morbidity in pediatric asthma are quite complex. Clinical impressions suggest that children with more severe asthma are likely to have increased functional morbidity (e.g., greater number of missed school days). However, there is also evidence that psychosocial factors, such as poor child adjustment, may be predictive of functional morbidity. A recent large-scale study of children with asthma found that the existence of clinically significant behavior problems was associated with poorer functional health status (e.g., hospitalizations, days of wheeze).3 It is unclear, however, whether asthma per se is related to a greater incidence of behavior problems in children.
The emotional and behavioral adjustment of children with asthma has been a focus of research, using various paradigms, over the past half century. Early impressions of psychosocial factors specific to pediatric asthma emphasized difficulties in separation and individuation from parents4 and associated anxiety.5 These first theorists speculated that the "wheeze" of asthma might be, in part, an expression of these underlying psychological difficulties. Over the past few decades, increasing understanding of the pathophysiology of asthma has diminished support for this view. More recent examinations of the link between asthma and difficulties in adjustment have emphasized more contextual factors, such as stress and medication management, that could result in adjustment difficulties.6,7
Approximately 30 years ago, researchers began to attempt systematic assessments of behavior problems or psychiatric disorders in the pediatric asthma population (see, for example, a study by Graham, Rutter, Yule, and Pless8). These studies indicated that the increased levels of behavior problems in children with asthma represented only a small (deemed "trivial") increase over those found in children without asthma.8,9 Research within the past two decades has, however, reported increased levels of behavior problems among children with asthma compared with other children.10-12 Consistent with early clinical impressions, there is some evidence that behavioral difficulties may be expressed primarily in the internalizing domain.7 In other words, children with asthma are more likely to exhibit anxious and depressive (i.e., internalizing) symptoms than oppositional or hyperactive (i.e., externalizing) symptoms. Clearer specification of this finding would be of benefit to clinicians and researchers alike. Health care professionals may be more likely to "miss" internalizing diagnoses if they should exist, because children with these profiles are less likely to cause difficulties at home, school, or even in the physician's office. Additionally, more specific information regarding the types of behavioral difficulties that children with asthma experience could begin to shed light on the mechanism that explains the link between illness and adjustment (e.g., is there an underlying physiological process that explains both?).
As research methods become more sophisticated, the complexity of the relationship between illness and behavioral adjustment becomes more evident. For instance, there is some evidence that the findings regarding behavioral difficulty in asthma may vary as a function of informant (e.g., parent vs clinician6). A recent multimethod assessment of adjustment demonstrated increased behavioral difficulties for children with asthma, relative to controls, by maternal report. These differences, however, were not found by other methods, such as child interview or behavioral observation.6
Prior research in childhood chronic illness in general has suggested that whether or not a study uses instrument norms or a control group as a basis for calculating group differences may also influence research findings. One meta-analysis investigating adjustment to pediatric physical disorders found that, across studies, risk for behavioral maladjustment was greatest when comparisons were made with norms rather than with study controls.13 However, a subsequent meta-analytic review of depression in children with chronic medical problems found the reverse pattern, namely, that greater differences in depressive symptoms were found when community controls, as opposed to norms, were used as a basis for comparison.14 Although it is not clear why these patterns of differences occur, it may be due to how carefully controls are matched in various studies. Clear specification of the basis for comparison across studies may clarify why inconsistencies are found in the literature investigating whether or not children with asthma are at increased risk for behavior problems.
In studies investigating psychological adaptation across the range of children with asthma, there is an indication that disease severity may play a role in behavioral adjustment.6,7 Intuitively, one might expect that children with more severe asthma have a greater number of illness-related stressors which, in turn, result in difficulties in adjustment. It is also possible, however, that children cope more or less well with asthma because of their personality and temperament or that coping with a chronic illness may provide a positive opportunity for child growth. Empirical findings regarding the relationship between asthma severity and behavioral adjustment have been inconsistent across studies. In some research, children with more severe asthma have been found to have more behavioral difficulty.6,7 Other research has demonstrated a curvilinear effect between asthma severity and behavioral difficulty, such that children with the mildest and those with the most severe forms of the illness have the most reported problems, whereas children with moderate asthma symptoms have the least.12 Still other studies failed to find any relationship between the severity of asthma and child adjustment.11,15
The following meta-analysis was conducted to assess the relationship between asthma and child behavioral adjustment over the past 25 years of research. Meta-analysis is a technique of summarizing a research literature using established quantitative methods. It is particularly useful when, as in the question of behavioral adjustment to asthma, research findings conflict to such an extent that a qualitative review of the literature might fail to clarify the essential research questions. Although meta-analytic reviews have investigated childhood adjustment to physical disorders in general,13 and depressive symptoms in children with chronic illnesses,14 no meta-analysis has focused expressly on behavioral adjustment in the pediatric asthma population. Specifically, this investigation sought to determine whether children with asthma were at increased risk for difficulties in behavioral adjustment. The question of whether adjustment problems were primarily in the internalizing domain was also assessed. Lastly, the extent to which disease severity was related to difficulties in behavioral adjustment was evaluated.