Pre-treatment predictors of treatment outcome in childhood anxiety disorders: a systematic review

As current strategies for improving the treatment of childhood anxiety disorders have yet to markedly improve outcomes, the focus of research has shifted to determining what variables can predict treatment outcome. At the same time, other research (e.g. Rapee et al., 2013) has postulated that the way we define treatment outcome; either categorically (endpoint) or continuously (rate of change) can have an impact on the results found. As such, this study aimed to conduct a broader systematic review of the literature, examining all researched predictors of treatment outcome for childhood anxiety disorders. The final sample included 47 articles and four dissertations. Article were included if the children were diagnosed with a primary anxiety disorder, and were under the age of 19 at the time of treatment. All articles must have had a sample size larger than 50, and reported pre –treatment variables as predictors of treatment outcome. Predictors researched by more than three articles were reviewed systematically. All other predictors were included in a summary table as no conclusions could be drawn at this time. Predictors were grouped into three main categories – child demographic, child diagnostic and parental psychopathology; and then broken down within these categories. Within each category, results separated by the type of outcome used (endpoint and rate of change) and then by the person who completed the outcome measure (diagnostic; clinician, parent and child). Results determined that all child demographic variables were not significant predictors of outcome, irrespective of outcome definition. There was some evidence to suggest that comorbid depression and externalizing disorders were associated with decreased treatment outcome for endpoint measures only. Similarly, higher symptom severity was associated with worse treatment outcome for endpoint measures only; however these results were not consistently found. When examining possible parental predictors, maternal anxiety was associated with treatment outcome using the endpoint measure only, although the direction of this relationship is currently unclear. The current study also found that the weight of the evidence shows that parental and paternal anxiety and, maternal and paternal depression was not associated with treatment outcome. However there was tentative evidence that measures of parental psychopathology was associated with poorer outcomes. The inconclusiveness of this evidence suggests that further research is required to confirm the specific relationships between parental psychological conditions and treatment outcomes. The current study also highlighted that significant results were most common found when using a diagnostic or clinician reported measure of outcome (particularly with endpoint) and for the child diagnostic and parental psychopathology predictors, a diagnostic or clinician reported measure was also more likely to find a significant result. These reports also highlight the importance of continuing to use these measures in research. The findings of the current study emphasize some of the challenge of this field of research and provide suggests for future research and clinical applications. These suggestions include the development of a measure to evaluate the quality of research into predictors, the examination of the interaction between possible predictors and focusing on understanding in more detail the characteristics of a child and their family before beginning treatment to develop a more individualized treatment rather that the current treatment manuals being used.