Predictors of psychological functioning in children with cancer: disposition and cumulative life stressors.

Traumatic stress models suggest that childhood cancer is a traumatic event that puts children at increased risk for adjustment problems and adverse psychological outcomes. However, the empiric evidence demonstrates that children with cancer are resilient, generally functioning as well as or better than their healthy peers despite the challenges of their cancer experience [1-5]. In studying resilience following potentially traumatic events, Bonanno and Diminich [6] argue that simply assessing for the absence of psychopathology is a more limited approach than comparing mean levels of pathology between individuals who have and have not been exposed to the stressor of interest. In regards to internalizing symptoms, a preponderance of the literature suggests that children with cancer demonstrate comparable or lower levels of symptoms relative to children without a history of serious illness [2, 7-11]. These findings suggest children who have experienced cancer are relatively resilient and adjusting well. This also highlights the importance of comparing the functioning of children with cancer to a reference group of children without history of serious illness; however, this has not been the norm. The absence of a control or normative comparison group in this literature carries additional methodological implications. Given that some distress is to be expected in the general population, it would be erroneous to assume that any symptoms of distress in children with cancer history are a result of their cancer experience. Such an approach risks overestimating the illness-related distress experienced in this population. A substantial literature exists suggesting that a subgroup of children with cancer experience significant adjustment problems, although most are doing well [5, 12]. However, few of these studies included control comparisons. Alternately, some studies, most notably the childhood cancer survivor study, have included sibling controls, focusing on the statistically greater symptomatology among survivors, despite that fact that both groups were doing exceptionally well [13, 14]. Thus, comparing the functioning of children with and without a history of illness is vital to our understanding of the extent to which children with cancer experience heightened distress. Given the evidence that children with cancer do not differ from healthy peers with regard to psychological functioning, any problems that children with cancer do experience may in fact be better attributed to factors other than cancer, such as premorbid functioning, family environment, social supports, temperament or disposition, and other stressful events. Indeed, children's psychological functioning has consistently been associated with the overall number of lifetime stressors experienced, with findings suggesting that more lifetime adversity predicts increased depression, anxiety, and posttraumatic stress symptoms [15, 16]. Importantly, children's cumulative stressful life events predict psychological outcomes above and beyond the experience of cancer [17]. Given these findings, the number of stressful life events experienced is one factor expected to significantly predict children's adjustment when controlling for their diagnosis of cancer. Disposition, or personality factors, has been shown to be important in accounting for individual differences in the psychological functioning of adults with cancer. Such personality factors have been studied in a variety of ways. Optimism is a trait that has been examined extensively and shown to be predictive of the adjustment of adults with cancer [18, 19]. Other studies have used a Five Factor Model (i.e., Neuroticism, Extraversion, Openness, Agreeableness, Conscientiousness) [20], demonstrating that such factors significantly predict adults ' adjustment to cancer when controlling for illness-related variables [21], as well as children's psychological functioning more generally [22]. Conceptually, optimism is considered a sub domain within the factor of extraversion. However, optimism is well established as a separately measured construct, and has been found to be especially pertinent to the psychological functioning of adults with cancer. Despite the apparent importance of disposition in predicting adjustment of adults with cancer, there is a dearth of research examining dispositional factors in the pediatric population. This is curious given that the constructs of temperament and personality are well established in children and these factors are thought to remain relatively stable from an early age [22, 23]. Given that children with a history of cancer appear to be adjusting well and disposition is salient to adults ' functioning, examining the possible role of dispositional factors is a critical next step in studying the psychological wellbeing of children with cancer. In the present study, we sought to examine psychological functioning in children with a history of cancer and a demographically matched comparison group of children without history of serious illness. We hypothesized that there would be no significant differences between children with cancer and healthy peers with regard to depression, anxiety, and posttraumatic stress symptoms. Secondly, we sought to examine what factors are predictive of children's psychological functioning, including the role of children's stressful life events and dispositional traits. We hypothesized that cumulative life stressors would significantly predict unique variance in children's adjustment. We further hypothesized that child disposition would significantly predict unique variance in children's depression, anxiety, and posttraumatic stress symptom scores when controlling for demographic background, health status (i.e., cancer versus healthy comparison), and stressful life events.