Schedule:
Friday, January 13, 2012: 8:30 AM
Independence B (Grand Hyatt Washington)
* noted as presenting author
Jeanine A. Webber, PhD, RSW,
Professor and Program Coordinator, Humber Institute of Technology and Advanced Learning, Toronto, ON, Canada
Susan B. Stern, PhD, Associate Professor, University of Toronto, Toronto, ON, Canada
Debra J. Pepler, PhD, CPsych, Distinguished Research Professor of Psychology, York University, Toronto, ON, Canada
Margaret Walsh, BA, Research Manager, Child Development Institute, Toronto, ON, Canada
Background & Purpose: Children with disruptive behaviour disorders experience a rate of comorbid disorders as high as 70 – 80% in clinical populations yet minimal evidence exists to inform treatment (Doss & Weisz, 2006; Greene et al., 2002; Kazdin & Whitley, 2006). The prognostic trajectories for children with comorbid disorders include more negative outcomes than for children with a single disorder. Despite having a lower incidence rate for behaviour disorders girls are more likely to experience comorbid disorders than boys (Abram et al., 2003). Girls with comorbid disorders also have poorer outcomes such as higher rates of substance abuse, and adult criminality (Angold et al., 1999) than girls with a single disorder. Consequently girls with comorbid difficulties are an especially vulnerable population. To date the few treatment studies that address comorbid conditions had mixed results (Rohde et al., 2004; Weiss et al., 2003). Therefore, this study examined the difference in treatment response between girls with comorbid externalizing and internalizing disorders and girls with externalizing disorders only to a gender sensitive treatment program consisting of concurrent parent management groups and cognitive-behaviour treatment groups for girls developed for disruptive disorders. It was hypothesized that girls with comorbid disorders would experience change at a slower rate and would still remain in the clinical range at the conclusion of treatment.
Methods: This study involved secondary data analyses from a quasi-experimental outcome study. Of the 81 girls from the original study's data set, 41 scored in the clinical range for both externalizing and internalizing disorders (comorbid group) and 40 scored in the clinical range for only externalizing disorders (noncomorbid group) on the CBCL (Achenbach, 1991) at pre-treatment. A hierarchical linear model was used to compare treatment response in externalizing scores over time between the two groups. Internalizing scores over time were examined for the comorbid group using a repeated measures ANOVA. To evaluate the clinical significance of the findings, the effect size, absolute risk reduction and numbers needed to treat were calculated.
Results: Girls with comorbid disorders experienced a significant reduction of both internalizing and externalizing symptoms. Externalizing scores were significantly different across time between the two groups, b = -1.02, p < .001. Surprisingly change for the comorbid group was steeper with a borderline large effect size in contrast to a gradual change and small effect size for the noncomorbid group for externalizing from pre- to post-treatment. A significant effect over time was detected for internalizing symptoms for the comorbid group even though treatment targeted disruptive behaviours. Only 1 in 7.4 girls, however, scored below the clinical range for both externalizing and internalizing disorders post-treatment in comparison to 1 in 5 girls scoring below the clinical range for externalizing in the noncomorbid group.
Implications: Girls with comorbid conditions benefited from treatment but the results underscore the need to target comorbidity in treatment, assessment and program design. These results also point to the need for further research on treatment development to address the serious problem of comorbidity in children's mental health and inform social work practice.
