Direction of Influence Between Posttraumatic and Depressive Symptoms during Prolonged Exposure Therapy among Children and Adolescents

Posttraumatic stress disorder (PTSD) is a common and chronic disorder among youth (Copeland, Keeler, Angold, & Costello, 2007). PTSD is frequently comorbid with major depressive disorder (MDD) and 48% of individuals with PTSD experience at least one major depressive episode (Kessler, Sonnega, Bromet, Hughes, & Nelson, 1995). Among youth, posttraumatic and depressive symptoms frequently co-occur (Copeland et al., 2007). Evidence regarding the relationship between posttraumatic and depressive symptoms over time is inconsistent. Some studies suggest that posttraumatic symptoms lead to depression. For example, in the National Comorbidity Survey, 78.4% of individuals with both PTSD and MDD reported that the onset of PTSD preceded that of MDD (Kessler et al., 1995). Specifically, among children and adolescents, anxiety symptoms have been found to lead to depressive symptoms over time, but not vice versa (Cole, Peeke, Martin, Truglio, Seroczynski, 1998). Conversely, other studies have suggested that depressive symptoms lead to posttraumatic symptoms more consistently than vice versa (Allon-Schindel, Aderka, Shahar, Stein, & Gilboa-Schechtman, 2010; King, King, McArdle, Shalev, & Doron-LaMarca, 2009). Finally, some studies have found that PTSD and MDD develop simultaneously (e.g., Shalev et al., 1998) and that reciprocal relations exist between posttraumatic and depressive symptoms (Erickson, Wolfe, King, King, & Sharkansky, 2001). Trauma-focused treatments for PTSD have been repeatedly shown to reduce both posttraumatic and depressive symptoms among adults (Harvey, Bryant, & Tarrier, 2003) and youth (Feeny, Foa, Treadwell, & March, 2004). However, little is known about the relationship between posttraumatic and depressive symptoms along the course of treatment. In a recent study among individuals with social anxiety disorder, changes in social anxiety were found to account for changes in depression during treatment, but not vice versa (Moscovitch, Hofmann, Suvak, & In-Albon, 2005). To our knowledge, no study has examined the anxiety-depression relationship along the course of treatment for PTSD. The present study addresses this gap by applying hierarchical linear modeling (HLM) techniques to examine the relationship between posttraumatic and depressive symptoms during treatment for PTSD. In addition, the present study is the first to examine this relationship among youth receiving treatment. The relationship between posttraumatic and depressive symptoms during treatment is of paramount importance as it can shed light on both mechanisms of change and psychopathology. We examined this relationship among children and adolescents during prolonged exposure (PE) therapy for PTSD. PE is a trauma focused cognitive-behavioral treatment rooted in emotional processing theory (Foa & Kozak, 1986). Recently, PE was adapted for treatment of children and adolescents (Foa, Chrestman, & Gilboa-Schechtman, 2008), and found to be effective in an open trial (Foa et al., 2008), as well as a randomized controlled trial (Gilboa-Schechtman et al., 2010). We examined the four possibilities regarding the relationship between posttraumatic and depressive symptoms over time: (a) changes in posttraumatic symptoms account for changes in depressive symptoms but not vice versa, (b) changes in depressive symptoms account for changes in posttraumatic symptoms but not vice versa, (c) changes in both posttraumatic and depressive symptoms account for changes in each other, and (d) changes in posttraumatic symptoms are unrelated to changes in depressive symptoms.