Child and adolescent obsessive–compulsive disorder (OCD) is a chronic and debilitating condition that
accrues significant concurrent and long-term risk to affected youth (Bolton, Luckie, & Steinberg, 1995;
Hanna, 1995; Piacentini, Bergman, Keller, & McCracken, 2003; Pine, Cohen, Gurley, Brook, & Ma,
1998). More common than once thought, the disorder affects between 0.5% and 2% of children and
adolescents (Flament et al., 1988; Heyman et al., 2003;Rapoport et al., 2000; Zohar, 1999), thus paralleling the prevalence rates reported within the adult population (Torres et al., 2006; Weissman et al., 1994). Growing awareness of the scope and impact of the disorder has been met with heightened research activity focused on identifying effective interventions, both psychosocial and psychopharmacological, for youth with OCD. Such work has generated an emerging evidence base and has spurred the publication of expert consensus guidelines (March, Frances, Kahn, & Carpenter, 1997) and practice parameters (American Academy of Child and

Adolescent Psychiatry, 1998) for the treatment of this disorder. Both sets of guidelines recommend exposurebased cognitive behavioral therapy (CBT), either alone or in conjunction with a serotonin reuptake inhibitor (SRI) as a frontline intervention for youth with OCD. Although not empirically based, such guidelines undoubtedly mark a big step forward for enhancing treatment for youth with OCD; however, there is still much to be done to further understand and improve the available treatments for these youngsters. In this article, we provide a brief discussion of the phenomenology of child and adolescent OCD and the theory underlying current treatment approaches. We then review the current state of the psychosocial treatment research literature, evaluating the specific studies comprising this literature base relative to the criteria for classification as an evidence-based intervention. We discuss mediators, moderators, and predictors of treatment outcome as well as the implications and clinical generalizability of findings to date. We conclude with a discussion of recommendations for best practice and future directions that stem from this body of work.

Emotional disturbances in children and youth occur at alarmingly high rates, are associated with a number of negative life consequences, and come at a tremendous cost to society. A Year Book of Australia report indicated that 20% of children between the ages of 12 and 16 had a significant mental health problem (Stanley, 2002). Anxiety disorders are the most frequently experienced mental health disorder in childhood and adolescence, with studies stimating a point prevalence of 5% to 10% and a lifetime prevalence of approximately 20% (Essau, Condradt, & Petermann, 2000; Shaffer, Fischer, Dulcan, & Davies, 1996). Research has demonstrated that anxiety and depressive
symptoms are highly related in child and youth populations (e.g., Dobson, 1985; Tannenbaum, Forehand, & Thomas, 1992). Estimates indicate approximately 2% to 5% of children and adolescents will suffer a major depressive disorder of clinical severity (Kashani et al., 1987; Lewinsohn, Clarke, & Rohde, 1994). Beyond the high prevalence rates, these emotional disorders are associated with a wide range of psychosocial impairments, tend to be chronic and unremitting in course, and are associated with significant risk for other psychological disorders if left untreated (e.g., Cole, Peeke, Martin, Truglio, & Seroczynski, 1998; Kashani & Orvaschel, 1990; Last, Hansen, & Franco, 1997; Orvaschel, Lewinsohn, & Seeley, 1995).

There has been a recent surge in the field of prevention research for children and youth. Given the potential of such approaches to impact on the incidence and prevalence of childhood emotional disorders, the need for evidence-based prevention is strong. Primary preventive interventions can be defined as either universal, selected, or indicated and targeted (Mrazek & Haggerty, 1994). Universal interventions target whole population groups, selective interventions involve children and youth identified as at risk of psychological problems, and indicated interventions target individuals identified with mild to moderate symptoms of a disorder (Mrazek & Haggerty, 1994). Universal prevention interventions conducted in the school context have many advantages, including reducing recruitment, screening, and attrition difficulties; reaching a broad range of children and adolescents with varying levels of risk for psychopathology; reducing stigmatization; enhancing peer support; and reducing psychosocial difficulties within the classroom—thus promoting learning and healthy development (Evans, 1999; Kubiszyn, 1999). Support for preventative outcomes based on the delivery of cognitive behavioral interventions in schools is growing.

The Queensland Early Intervention and Prevention of Anxiety Project (Dadds, Spence, Holland, Barrett & Laurens, 1997) represented the first cognitive behavioral trial for prevention of childhood anxiety. This study targeted children (ages 7 to 14 years) who were disorder-free but exhibited anxious symptomatology (indicated prevention; Mrazek & Haggerty, 1994) as well as children who met criteria for an anxiety disorder but were in the less severe range (early intervention; Mrazek & Haggerty, 1994). Screening identified 128 eligible participants who were randomly allocated to either an intervention or a control condition. Diagnostic status was used as an outcome measure, and results were favorable. Both groups demonstrated improvement immediately postintervention; however, by 6-month follow-up, the improvement was maintained in the intervention group only. No differences between groups were evident at 12-month follow-up; however, at the 2-year follow-up, intervention effectiveness was demonstrated through the reduction of existing rates of anxiety disorder and prevention of the onset of new
anxiety disorders (Dadds, Spence, Laurens, Mullins,& Barrett, 1999). Consistent with prior research (Last, Perrin, Hersen, & Kazdin, 1996), regardless of intervention status, participants in this study showed a general improvement across time; results further revealed gender (female), parental anxiety and pretreatment severity predicted poor response to intervention (Barrett, Dadds, & Rapee, 1996; Cobham, Dadds, & Spence, 1998). This study emonstrated that anxiety disorders and the number of children at risk of anxiety can be successfully reduced through selected school-based cognitive–behavioral intervention. An interesting outcome was putative delay in intervention effects, which is consistent with the results of a similar prevention trial for adolescent depression (Jaycox, Reivich, Gillham, & Seligman, 1994).

Research into adult anxiety has shown that anxious adults frequently display cognitive biases in the processing of environmental stimuli (MacLeod, Mathews, & Tata, 1986). Compared with nonclinic subjects, they are more likely to interpret ambiguous material as threatening and tend to think that negative threatening events are more likely to happen to themselves than anyone else (Butler & Mathews, 1983). One question which has remained
untested is whether cognitive biases in anxious adults are established in adulthood or were already present at a young age. Retrospective studies have indicated that anxious adults often report having experienced high anxiety as children, raising the question of whether some of these cognitive biases were already present in childhood (Mattison, 1992). In studies of aggressive children, for example, Dodge (1986) has found that such children display a bias toward excessive attributions of hostile intentions in others. However, to date, there has not been similar published research with other groups of children.

Some recent research has attempted to examine the way in which feared outcomes are represented in long-term memory (Campbell & Rapee, 1994; Lovibond & Rapee, 1993). These studies have indicated that children seem to represent threatening outcomes in a very similar way to adults. Specifically, feared outcomes seem to be organized along two major factors: physical threat (physical harm) and social threat (negative evaluation). Another interesting research question, then, is whether people with different symptomatologies (predominantly social or physical fears), and different anxiety diagnoses, manifest different interpretation and response biases to ambiguity related specifically to physical or social situations.

In addition to the important role which cognitive factors may play in the maintenance of child anxiety, a large body of research has indicated that child psychopathology generally needs to be understood in the context of family interactional patterns (Dadds, 1987; Patterson & Reid, 1984). While direct observational studies of family processes with anxious children are rare (cf. Dadds, Barrett, Rapee, & Ryan, in press), there exists indirect evidence to support the role of family processes in the development of childhood anxiety.

Epidemiological studies (Klein & Last, 1989) point to the familial transmission of anxiety disorders. Studies of parents of anxious children find that they tend to selectively focus on future negative outcomes for their children’s current activities (Kortlander, Kendall, & Chansky, 1990). Krohne and Hock (1991) have suggested a “two-process model” that deals with the relationship between specific styles of parental child-rearing and coping dispositions in the children. Empirical tests of their model show that high anxiety in a child is significantly related to frequent negative feedback and parental restriction (Krohne & Hock, 1991). Hence, it is plausible that anxious children might learn to expect negative consequences for their behavior and as a result become fearful and avoidant. Recent clinical studies have further confirmed that the involvement of families in the treatment of anxious children is more effective than just treating the child (Barrett, Dadds, Rapee, & Ryan, in press; Dadds, Heard, & Rapee, 1991; King,Hamilton, & Ollendick, 1988).

TREATMENT OF CHILDHOOD and adolescent anxiety has garnered increasing attention over the last decade. For the majority of children, anxiety is a common, functional, and transitory experience (Last, Perrin, Hersen, & Kazdin, 1996), the nature and intensity of which varies, at least in part, according to the child’s developmental stage. For example, young children often experience anxiety when separated from main attachment figures or if exposed to dark, unfamiliar places. In comparison, the anxieties expressed by adolescents relate more commonly to social identification and interpersonal issues. Unfortunately, for a large proportion of children and adolescents, anxiety may increase in intensity, becoming chronic and developmentally dysfunctional.
For these young people and their families, normal daily activities are usually disturbed and anxiety becomes a pervasive, intrusive problem requiring clinical intervention (Messer & Beidel, 1994). This is reflected in the fact that anxiety disor-ders are the most prevalent type of psychological disorder experienced by children and teenagers (Albano, Chorpita, & Barlow, 1996; Bernstein & Borchardt, 1991). Of further relevance to the present discussion is the observation that for those children and adolescents who experience chronic anxiety, but remain untreated, the prognosis is significantly poorer (Dadds, Barrett, & Cobham, 1997). Keller et al. (1992) assessed past and present psychopathology in 725 children and adolescents aged 6 to 19 years who were recruited in order to study the effects of parental affective illness on children.
Fourteen percent of the children were found to have a history of an anxiety disorder, and of these children, only 34% were free of an anxiety diagnosis at the assessment period. The average duration of the disorder at the time of assessment was reported as 4 years. Other research noted that children with an anxiety disorder were still likely to fulfil diagnostic criteria up to 8 years after the onset of the disorder (Kovacs & Devlin, 1998). There is some indication, then, that childhood disorders may be more chronic and enduring than initially thought. Initial approaches to the treatment of childhood anxiety used elements and processes from adult treatment models, derived from adult-based theories, with terminology adapted for a youth population. In this regard, the childhood anxiety field is not unlike many others in clinical child psychology that have been built on the foundations of adult treatment paradigms. More recently, however, there has been a growing recognition of the need to consider developmental factors as they relate to the etiology, assessment, and treatment of various childhood disorders. Given the potential for anxiety problems to occur across the lifespan, as well as the established links between childhood anxiety disorders and psychological disorder later in life (Kovacs & Devlin, 1998), the application of a developmental perspective in the treatment of childhood anxiety seems warranted.
The impact of developmental factors is further mediated by the cultural context and background of the family and society to which the young person belongs. One illustration is the observation that Portuguese children, from a nonclinical population, report more fears on average than do English children (Fonseca, Yule, & Erol, 1994). Moreover, a perusal of Portuguese research on parent–child relationships indicates that it is culturally appropriate for children as old as 7 years to sleep in their parents’ bedroom; a custom that would find less favour within Anglo-Saxon-based cultures. It has been argued that a major failing of current clinical research is its dependence upon a culturally narrow (western, middle-class) definition of psychopathology and mental health (Kaslow & Thompson, 1998). A careful examination of practices in countries of non-English-speaking background would likely lead to a re-think of our culturally bound definitions of what is developmentally appropriate and what warrants clinical intervention.