CBT specific process in exposure-based treatments: Initial examination in a pediatric OCD sample

Abstract

Cognitive-behavioral theory and empirical support suggest that optimal activation of fear is a critical component for successful exposure treatment. Using this theory, we developed coding methodology for measuring CBT-specific process during exposure. We piloted this methodology in a sample of young children (N=18) who previously received CBT as part of a randomized controlled trial. Results supported the preliminary reliability and predictive validity of coding variables with 12 weeks and 3 months treatment outcome data, generally showing results consistent with CBT theory. However, given our limited and restricted sample, additional testing is warranted. Measurement of CBT-specific process using this methodology may have implications for understanding mechanism of change in exposure-based treatments and for improving dissemination efforts through identification of therapist behaviors associated with improved outcome.

Introduction

Pediatric obsessive–compulsive disorder (OCD) has a prevalence rate of 2–3% (Douglass et al., 1995, Rapoport and Inof-Germain, 2000) and is associated with significant impairment in social, academic, and familial functioning (Piacentini, Bergman, Keller, & McCracken, 2003). Left untreated, childhood OCD is often unremitting into adulthood and associated with significant and costly adult disability (Flament et al., 1990, Thomsen and Mikkelsen, 1995). Although the core features of OCD are similar across the lifespan, OCD in childhood has unique characteristics in terms of developmental abilities (e.g., limited awareness or insight into cognitions, emotional state, or OCD symptoms), family context (e.g., reliance on parents for guidance, OCD-related family accommodation (Storch et al., 2007), and OCD phenomenology (e.g., more scrupulosity and “not just right” compulsions (Garcia et al., 2009)

Cognitive-behavioral therapy (CBT) with exposure and response prevention (E/RP) has been shown to be efficacious and is a first line treatment alone or in combination with selective serotonin reuptake inhibitor (SSRI) for pediatric OCD (POTS Study Team, 2004). Meta-analysis shows a large average effect size (d=1.45) for CBT across treatment trials (Watson & Rees, 2008). Despite the demonstrated efficacy of combined treatment, concerns remain regarding adverse drug reactions, the use of medication in children under the age of 8, and the unclear impact of medication on exposure-based learning in CBT (Freeman et al., 2007), leading to increased interest in research aimed at improving outcome with CBT alone.

CBT for OCD contains several procedural ingredients, such as psychoeducation, hierarchy building, exposure and response prevention, cognitive strategies, reward programs, family/parent training, and relapse prevention (March and Mulle, 1998, Piacentini et al., 2007). Of these ingredients, exposure and response prevention is the procedure thought to be necessary and sufficient for therapeutic change to occur (Tyron, 2005). During this procedure, the individual is taught to approach fear-producing stimuli (exposure) while preventing fear-reducing behaviors, such as compulsions or other avoidance strategies (response prevention) (Himle & Franklin, 2009). Although the precise mechanisms by which exposure and response prevention lead to fear reduction have yet to be empirically confirmed (Tyron, 2005), CBT theory provides a framework for understanding the mechanisms that may be responsible for therapeutic change.

According to CBT theory, the “disorder mechanisms” responsible for the development and maintenance of anxiety and avoidance in OCD are based on Mowrer’s (1960) two-stage theory. In this model, a conditioned stimulus (e.g., thought, image, object) is paired with an aversive unconditioned stimulus and thereby comes to elicit a conditioned response (e.g., fear, anxiety). Once the conditioned anxiety response is acquired, it serves as a discriminative stimulus that evokes avoidance or escape behaviors (i.e., compulsions), which in turn are negatively reinforced by the reduction of anxiety. In the case of pediatric OCD, a family member may engage in the escape behavior for the child by providing accommodation or reassurance, which also reduces anxiety and thus negatively reinforces both the child and the parent. Therefore, according to this model, the disorder mechanisms involved in OCD are respondent conditioning and negative reinforcement. Although more recent evidence suggests that anxiety may develop for reasons other than respondent conditioning (Menzies & Clarke, 1995), negative reinforcement is a key component of the CBT model of OCD maintenance and forms the foundation of the treatment rationale.

Exposure and response prevention (ERP) is thought to activate particular “treatment mechanisms” that disrupt disorder mechanisms. In this procedure, anxiety is elicited and escape/avoidance behaviors are prevented, thereby activating the treatment mechanisms of habituation and extinction. Habituation refers to decrement of the anxiety response due to sustained contact (within session or trial habituation) and repeated presentation (between-session or trial habituation) of the anxiety-eliciting stimulus (Groves & Thompson, 1970).Thus, the uninterrupted experience of optimal anxious arousal, activated by the procedure of exposure and response prevention, leads to anxiety reduction via the mechanism of habituation. In addition to reducing the anxiety response, habituation within and across trials is also thought to promote the emotional processing of fear by providing the individual with direct, corrective information that disconfirms obsessional fears (Foa & Kozak, 1986). The ERP procedure also activates the mechanism of extinction: by preventing anxiety reducing behavior in the presence of the anxiety response (i.e., the discriminative stimulus), anxiety-reducing behaviors cannot be negatively reinforced. Over time, this reduces the frequency of compulsions/avoidance and alters the function of the anxiety response, such that the discriminative stimulus becomes an extinction stimulus that no longer evokes anxiety-reducing behavior.

Therefore, according to CBT theory, anxious arousal plays a key role in exposure efficacy: an optimal increase in anxiety must occur for therapeutic mechanisms to be activated (Foa & Kozak, 1986). Research examining anxious arousal during exposure therapy supports this notion. For example, Kozak, Foa, and Steketee (1988) examined anxious arousal, within session habituation, and across session habituation during exposure therapy in 14 adults with OCD. Results confirmed that all three processes occurred. Importantly, greater intensity of anxious arousal during exposure and greater habituation across sessions predicated better post-treatment ratings of obsessional fear. In a study of exposure therapy for adult females with PTSD, Foa, Riggs, Massie, and Yarczower (1995) found that those who displayed more intense facial fear expressions during the first exposure benefited more from treatment than those with less intense fear expressions. However, it is important to note that extreme levels of arousal can obstruct habituation (Foa et al., 1983) and impede the child or parent's ability to refrain from engaging in avoidance or compulsive behavior. Therefore, exposures that elicit a moderate level of anxiety are thought to maximize within-session fear reduction and treatment tolerability, as well as reduce the likelihood of treatment dropout (Norton, Hayes-Skelton, & Klenck, 2011).

Given the importance of anxious arousal in CBT for OCD, it is likely that CBT-specific process variables that influence the amount of anxiety experienced by the child during exposures also influence treatment outcome. Specifically, by “CBT-specific process variables” we are referring to child, parent, or therapist behaviors that may have a functional impact (i.e., increase or decrease) on anxiety during exposure procedures. Indeed, research suggests that processes that function to reduce anxiety are counter-productive, most likely because they prevent activation of treatment mechanisms (Clark, 1999, Himle and Franklin, 2009, Salkovskis, 1996). For example, studies of exposure process in adults with OCD or other anxiety suggest that several anxiety reduction strategies can be detrimental to outcome, such as overt or covert compulsions, behavioral or cognitive avoidance, thought-suppression, distraction, and availability or utilization of a safety aid (Parrish, Radomsky, & Dugas, 2008). Research on family accommodation in pediatric OCD suggests that families who continue to provide accommodation during the course of CBT may be less likely to be treatment responders (Merlo, Lehmkuhl, Geffken, & Storch, 2009). In contrast, anxiety promoting or increasing processes during exposure are thought to be beneficial in achieving optimal activation, such as exposure content that involves contacting or directing focus to feared stimuli (Craske et al., 1991, Foa et al., 1980, Grayson et al., 1982).

Despite this evidence that CBT-specific process variables do impact exposure benefit, manualized protocols for CBT with pediatric OCD provide very little guidance as to precisely how to achieve and maintain an appropriate level of anxiety during an exposure. For example, protocols vary in terms of the types of tools therapists are directed to use, such as those that encourage (March and Mulle, 1998, Piacentini et al., 2007) versus discourage (Freeman & Garcia, 2008) the use of cognitive strategies during exposures. As such, little is known about what therapists do or say to achieve optimal activation during exposures (therapist CBT-specific process variables). Furthermore, the role of patient behaviors in facilitating or diminishing exposure benefit is also unclear; although anxiety reducing strategies are thought to be counter-productive, little is known about patient and parent behaviors associated with “success” (child and parent CBT-specific process variables) and how therapist, patient, and parent behaviors interact during an exposure trial.

Systematic examination of CBT-specific process variables during exposures may help us identify processes that are most closely associated with therapeutic change. By identifying this relationship, we may come to better understand the mechanism of change in exposure therapy (e.g., confirm or modify existing CBT theory). Furthermore, by focusing on treatment processes and procedures that most effectively activate the mechanism of change, we may be able to increase potency and simplify CBT for pediatric OCD (Kazdin, 2009). Finally, without explicit examination of CBT-specific process, theoretically based therapist behavior that likely underlies successful treatment of CBT for OCD may remain “in the heads” of treatment experts and unable to be disseminated to other therapists.

An important first step in understanding mechanism of change during CBT for pediatric OCD is the development of methodology to systematically examine CBT-specific processes during exposures. Although researchers have examined patient-level predictors and moderators of treatment outcome in an effort to understand differential response to treatment (e.g., alliance) (Keeley, Geffken, Ricketts, McNamara, & Storch, 2011), we have been largely unable to study CBT-specific process questions due to lack of appropriate methods.

The current study sought to examine CBT-specific processes that relate to the efficacy of exposure in CBT for pediatric OCD. Given that no previous research has examined process variables in this way, we developed and piloted coding methodology designed to capture observable therapist, child, and parent behaviors. The primary aim of the current study was to develop the coding methodology guided by CBT theory regarding optimal anxiety arousal, and to pilot initial reliability and predictive validity using a sample of children who completed exposures as part of a study examining efficacy of CBT for pediatric OCD.