Symptom differentiation of anxiety and depression across youth development and clinic-referred/nonreferred samples: An examination of competing factor structures of the Child Behavior Checklist DSM-oriented scales MAGGI PRICE, a CHARMAINE HIGA-MCMILLAN, a CHAD EBESUTANI, b KELSIE OKAMURA, c BRAD J. NAKAMURA, c BRUCE F. CHORPITA, d AND JOHN WEISZ e a University of Hawaii, Hilo; b Duksung University, Seoul; c University of Hawaii, Manoa; d University of California, Los Angeles; and e Harvard University Abstract This study examined the psychometric properties of the DSM-oriented scales of the Child Behavior Checklist (Achenbach, Dumenci, & Rescorla, 2003) using confirmatory factor analysis to compare the six-factor structure of the DSM-oriented scales to competing models consistent with developmental theories of symptom differentiation. We tested these models on both clinic-referred (N ¼ 757) and school-based, nonreferred (N ¼ 713) samples of youths in order to assess the generalizability of the factorial structures. Although previous research has supported the fit of the six-factor DSM-oriented structure in a normative sample of youths ages 7 to 18 (Achenbach & Rescorla, 2001), tripartite model research indicates that anxiety and depressive symptomology are less differentiated among children compared to adolescents (Jacques & Mash, 2004). We thus examined the relative fit of a six- and a five-factor model (collapsing anxiety and depression) with younger (ages 7–10) and older (ages 11–18) youth subsamples. The results revealed that the six-factor model fit the best in all samples except among younger nonclinical children. The results extended the generalizability of the rationally derived six-factor structure of the DSM-oriented scales to clinic-referred youths and provided further support to the notion that younger children in nonclinical samples exhibit less differentiated symptoms of anxiety and depression. Although symptoms of anxiety and depression tend to coexist throughout the life span, empirical evidence indicates that rates of comorbidity are highest among youths (Rohde, Lewin- sohn, & Seeley, 1991). High rates of comorbidity have led some researchers to conclude that anxiety and depression actu- ally represent a unitary construct in youths (e.g., Achenbach, Connors, Quay, Verhulst, & Howell, 1989; Brady & Kendall, 1992; Jacques & Mash, 2004). Research also indicates that anxiety and depression symptom differentiation in youths may differ as a function of psychopathological disturbance and/or age (cf. Brady & Kendall, 1992). Such research has led some to question the validity of the current conceptualiza- tions of anxiety and depressive disorders in the DSM (Ameri- can Psychological Association, 2000). The difficulty discrimi- nating between anxiety and depression coupled with the high rates of comorbidity in both adult and child populations suggest that depression and anxiety are strongly related to one another and therefore may not be best conceived as separate and discrete disorders (e.g., Lahey et al., 2008; Watson, 2005; Higa-McMillan, Smith, Chorpita, & Hayashi, 2008). Treatments have also more recently begun to be developed and tested to treat this broad class of emotional problems and disturbances related to anxiety and depression, such as the Unified Protocol for Treatment of Emotional Disorders in Youth (Ehrenreich, Goldstein, Wright, & Barlow, 2009). Proposed changes for the upcoming fifth addition of the DSM reflect this growing concern. For example, although a mixed anxiety/depression disorder currently exists in the ap- pendix of the text revision of the fourth edition of the DSM, the Mood Disorders workgroup has proposed that it be in- cluded in the fifth edition as a separate diagnostic category (Fawcett, 2009). Although research in this area is growing in the adult literature, it is critical that research in develop- mental psychopathology examine the implications of devel- opment and severity of symptoms on the structural similari- ties and differences between anxiety and depression. Comorbidity and Symptom Severity The high rate of comorbid anxious and depressive symptom- ology in youths has been well established in the research lit- erature (e.g., Kovacs, Gatsonis, Paulauskas, & Richards, 1990; Masi, Mucci, Favilla, Romano, & Poli, 1999; van Lang, Ferdinand, Ormel, & Verhulst, 2006). In a review of re- search studies that examined anxiety and depression comor- bidity in youths, Brady and Kendall (1992) found that comor- bidity rates of the studies assessed ranged from 15.9% to Address correspondence and reprint requests to: Charmaine Higa-McMillan, 200 West Kawili Street, Hilo, HI 96720; E-mail: higac@hawaii.edu. Development and Psychopathology 25 (2013), 1005–1015 # Cambridge University Press 2013 doi:10.1017/S0954579413000333 1005