Attention Bias Modification Treatment Augmenting Effects on Cognitive Behavioral Therapy in Children With Anxiety: Randomized Controlled Trial

NEW RESEARCH

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Attention Bias Modification TreatmentAugmenting Effects on Cognitive Behavioral

Therapy in Children With Anxiety:Randomized Controlled Trial

Tomer Shechner, PhD, Adi Rimon-Chakir, MA, Jennifer C. Britton, PhD,Danny Lotan, MA, Alan Apter, MD, Paul D. Bliese, PhD,

Daniel S. Pine, MD, Yair Bar-Haim, PhD

Objective: Attention bias modification treatment (ABMT) is a promising novel treatment foranxiety disorders, but clinical trials have focused largely on stand-alone formats among adults.This randomized controlled trial examined the augmenting effects of threat-based ABMT oncognitive behavioral therapy (CBT) in clinically anxious youth. Method: Sixty-three treatment-seeking children with anxiety disorder were randomly assigned to 1 of the following 3 treatmentgroups: ABMT þ CBT; ABMT placebo þ CBT; and CBT-alone. Participants in the 2 ABMT con-ditions received repeated training on dot–probe tasks either designed to shift attention away fromthreats (active) or designed to induce no changes in attention patterns (placebo). Primary outcomemeasures were frequency and severity of anxiety symptoms as determined by a clinician using asemi-structured interview. Self- and parent-rated anxiety measures and threat-related attentionbias scores were also measured before and after treatment. Results: Both the active and placeboABMT groups showed greater reductions in clinician-rated anxiety symptoms than the CBT-alonegroup. Furthermore, only the active ABMT group showed significant reduction in self- or parent-rated anxiety symptoms. Finally, all groups showed a shift in attention patterns across the study,starting with a bias toward threat at baseline and shifting attention away from threat aftertreatment. Conclusions: Active and placebo ABMT might augment the clinical response to CBTfor anxiety. This effect could arise from benefits associated with performing computer-basedparadigms such as the dot–probe task. Given the absence of group differences in attention-biaschanges during treatment, possible mechanisms and methodological issues underlying theobserved findings are discussed. Clinical trial registration information—Augmenting Effects ofABMT on CBT in Anxious Children: A Randomized Clinical Trial; http://clinicaltrials.gov/;NCT01730625. J. Am. Acad. Child Adolesc. Psychiatry, 2014;53(1):61–71. Key Words: anxiety,attention bias, attention bias modification treatment (ABMT), cognitive behavioral therapy (CBT)

he development of easily disseminated, safe,and efficacious treatments is an important

To that end, attention bias modification treatment(ABMT) shows promise based on its ability totarget threat-related attention biases1,2 and asso-ciated heightened anxiety in adults.3-5 A smallseries of randomized controlled trials also sug-gests the potential efficacy of ABMT in pediatricanxiety.6-10 The current RCT examined the degree

Clinical guidance is available at the end of this article.

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to which threat-focused ABMT augments theresponse to cognitive behavioral therapy (CBT),an established treatment for pediatric anxietydisorders.

ABMT emerged from work linking anxiety tothreat-related biases in attention. Anxious in-dividuals commonly show excessive vigilancetoward minor threats.2 The dot–probe task is1 common method for quantifying such threat-related attention biases.11 In this task, a pair ofstimuli, 1 threat and another neutral, appearsconcurrently in 2 different spatial locations on acomputer screen. Their offset is followed by aprobe that appears in the location previously

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occupied by 1 of the 2 stimuli. Allocation ofattention is measured by the reaction time (RT)difference for identifying probes across the 2spatial conditions. A faster RT to probes appear-ing in the location previously occupied by threat-related stimuli, relative to probes appearing in thelocation of neutral stimuli, indicates an attentionbias toward threat.

ABMT uses the dot–probe task not merely tomeasure attention biases but also to implicitlymodify such biases in anxious individuals. Dur-ing ABMT, the location of the probe is manipu-lated to implicitly train attention. For example,training intended to reduce bias toward threatrepeatedly presents probes in the location of theneutral rather than the threat stimulus. Over time,an implicitly learned bias away from threat isinduced because such contingency provides pre-diction about target location.1

Because CBT and ABMT may target differentcognitive aspects of anxiety, they may providecomplementary benefits for anxious children.CBT modifies explicit and voluntary attentionthrough verbal intervention (top–down ap-proach); ABMT alters implicit and involuntaryattention biases through computer-based train-ing (bottom–up approach). Thus, ABMT mayaugment the response to CBT. To date, only1 study has examined this potential synergisticeffect in adult patients with generalized anxietydisorder.12 However, this study tested only theapplication of these 2 interventions together in anopen trial without a control group affording a testof the augmenting effects of ABMT on CBT.

Although recent studies suggest that anxiouschildren, like anxious adults, may also manifestattention bias toward threat,13 more ABMTstudies focus on anxious adults than on anxiouschildren. Only 2 studies to date on threat-focusedABMT in clinically anxious children found pre-liminary evidence of efficacy.6,10 And yet, as insimilar RCTs of other computer-based treat-ments,7,8 ABMT was offered as a stand-alonetreatment6 or compared only with the 2 ABMTgroups without including a CBT-alone group.10

Available data in pediatric anxiety suggest thatmedications augment response to CBT.14,15 ABMTmight provide similar augmenting benefitswithout the potential adverse side effects associ-ated with medication. The current study examinedthe clinical response to CBT in groups of anxiouschildren randomized to 1 of 3 treatments as fol-lows: CBT with active ABMT (ABMTþ CBT); CBTwith placebo ABMT (ABMT placebo þ CBT); or

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CBT with no additional intervention. The studytested the hypothesis that children randomized toABMT þ CBT would show greater reduction inanxiety symptoms than children randomized toeither of the other 2 treatments.

METHODParticipantsParticipants were children or adolescents seeking treat-ment in a large child anxiety clinic (mean age ¼ 11.5years, SD ¼ 2.91, range ¼ 6.5–18). Children were invitedto enroll in the study if, based on a structured psychi-atric interview, they met DSM-IV criteria for separationanxiety disorder (SAD), social phobia (SoPh), specificphobia (SpPh), or generalized anxiety disorder (GAD).Exclusion criteria were as follows: lifetime history ofpsychosis; a clinical judgment that the child could notcomply with CBT; a primary diagnosis of post-traumaticstress disorder (PTSD), obsessive compulsive disorder(OCD), or selective mutism.

Of 119 assessed children, 63 who met inclusioncriteria agreed to participate. All 63 children receivedCBT and were randomly assigned to 1 of 3 groups:ABMT condition (ABMTþCBT), trained to induce anattentional bias away from threat (n ¼ 18); attentionbias placebo training (ABMT Placebo þ CBT) (n ¼ 25);CBT-alone, with no ABMT add-ons (n ¼ 20). Differ-ences in sample sizes in the 3 groups were the result ofusing random assignment. Of the 63 children assignedto the study, 8 children were not able to complete it,resulting in a total of 55 participants who wereincluded in the final analysis (ABMT þ CBT, n ¼ 15;ABMT placebo þ CBT, n ¼ 22; CBT-alone, n ¼18). Thissample size is consistent with our power calculation.Based on a previous study, in the same clinic,6 we usedeffect sizes of Cohen’s d ¼ 2.10 for the Anxiety Disor-ders Interview Schedule (ADIS) symptom count andd ¼ 2.25 for symptom severity to calculate the requiredsample size with 80% power, yielding an estimate of 15participants per group.

Sample demographics are presented in Table 1. Thefinal sample included 7 anxious children diagnosedwith comorbid ADHD: 2 children in the ABMT group,2 children in the ABMT placebo group, and 3 in theCBT-alone condition. All of these patients receivedpharmacological treatment (methylphenidate) asdescribed in Table 1.

Materials and TasksAnxiety Disorders Interview Schedule for DSM-IV:C/P (ADIS). Diagnosis was established with a struc-tured psychiatric interview, the ADIS for DSM-IV:C/P,16 which assesses the major anxiety, mood, andexternalizing DSM-IV disorders experienced by chil-dren and adolescents 7 to 18 years old. Patients andparents are presented with the same detailed list ofsymptoms (e.g., “when you are not with your parents,

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TABLE 1 Demographics and Pretreatment DSM-IV Diagnoses Among Completers Across the 3 Treatment Groups

Demographics, m (SD) ABMT n ¼ 15 ABMT-Placebo n ¼ 22 CBT Alone n ¼ 18 Statistics

Age 11.5 (2.87) 11.6 (2.90) 10.18 (3.09) F2,52 ¼ 0.844SES 3.20 (0.56) 3.36 (0.58) 3.24 (0.90) F2,51 ¼ 0.300Boys, n 8 15 8 c2

(2) ¼ 0.310Girls, n 7 7 10

Anxiety Dx, n (%)GAD only 3 (20) 4 (18) 4 (20)SAD only — 2 (9) 2 (11)SoPh only — — 1 (6)SpPh only 5 (33) 4 (18) 3 (17)GAD and SAD 2 (13) 3 (14) 2 (11)GAD and SoPh — 2 (9) 1 (6)GAD and SpPh 1 (7) 2 (9) 1 (6)SAD and SpPh 2 (13) 1 (5) 2 (11)SoPh and SpPh — 2 (9) —

GAD and SAD and SpPh 1 (7) 1 (5) 1 (6)GAD and SpPh and SoPh 1 (7) 1 (5) 1 (6)

Comorbid Dx, n (%)ADHD 2 (13) 2 (9) 3 (17) c2

(2) ¼ 0.518Medication, n (%)

SSRIs 1 (7) 4 (18) 2 (11)Stimulants 2 (13) 2 (9) 3 (17)Total meds, % 13 27 33 c2

(2) ¼ 0.390

Note: Statistics report F and c2 values. Because of the small number of observations in diagnosis (Dx) cells, only descriptive statistics are reported.Medication at pretreatment. All medication remained constant during trial. ABMT ¼ attention bias modification training; ADHD ¼ attention-deficit/hyperactivity disorder; CBT ¼ cognitive behavioral therapy; GAD ¼ generalized anxiety disorder; meds ¼ medications; SAD ¼ separation anxietydisorder; SES ¼ socioeconomic status; SoPh ¼ social phobia; SpPh ¼ specific phobia; SSRIs ¼ selective serotonin reuptake inhibitors.

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do you worry a lot that something bad might happento them, like they might get sick or hurt and die?”) towhich they have the option to respond “yes/no/other.” In line with the DSM-IV criteria, if patients orparents report sufficient numbers of symptoms (e.g.,3 items for simple phobia, 5 items for social anxiety),they meet criteria for the disorder. Once symptomcriteria are met, patients and parents are asked aboutthe severity of interference by the symptoms on a scaleranging from 0 to 8, with scores less than 4 indicatingsubthreshold levels of a symptom. If clinical severity isreported to be 4 or greater, a DSM-IV disorder isdiagnosed. The ADIS possesses excellent test–retestreliability for both symptom scales and diagnoses,17

and has been translated into Hebrew in collaborationwith the original authors. Interviewers were psychol-ogy graduate students who were trained on ADISadministration and reached 85% reliability criterionwith an experienced psychologist. Two clinical psy-chologists supervised all the interviews and helpedresolve any clinical or diagnostic issues that emerged.

Screen for Child Anxiety Related Emotional Disorders(SCARED). The SCARED is a 41-item parent and childreported questionnaire, measuring DSM-IV–definedanxiety disorder symptoms (e.g., “My child is aworrier”—parent version; “I am nervous”—childversion) in children and adolescents 7–19 years old).

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The scale measures symptoms of separation anxiety,generalized anxiety disorder, panic disorder, socialphobia, and school phobia, on a 3-point scale (0 ¼ nottrue or hardly true; 1 ¼ somewhat true or sometimestrue; 2 ¼ very true or often true). SCARED total andsubscale scores can be obtained by summing acrossrelevant items. The SCARED is a reliable and validchild anxiety instrument18 that has been extensivelyused in clinical and research contexts in Israel.6 In linewith the SCARED recommendations, a clinicianexplained all items in the questionnaire for childrenyounger than 10 years. In the current study we usedthe average of the total SCARED scores reported by thechildren and their parent as an outcome measure.Cronbach’s a coefficients in the current study were 0.88for child-report and 0.91 for parent-report.

Demographic Questionnaire. This questionnaire con-tained a series of demographic questions for descrip-tive and comparative purposes. For socioeconomicstatus (SES), participants rated the total monthly in-come in relation to the average family income on a5-point scale (1 ¼ much below the average; 2 ¼ belowaverage; 3 ¼ average; 4 ¼ above average; 5 ¼ muchabove average relative to the national average of 12,345NIS published by Israel’s Central Bureau of Statistics.

The Dot–Probe Task. The dot–probe task used tomeasure threat-related attention bias in the current

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study comprised 160 trials. Each trial began with a grayfixation cross (20�20 mm) in the center of the screen for500 milliseconds, followed by a face pair display for500 milliseconds. The face stimuli were photographs of12 actors (6 males), with closed-mouth expressions,taken from the NimStim set,19 each contributing 2pictures of the same actor: 1 expressing disgust and theother a neutral expression. Faces were presented inDisgust–Neutral or Neutral–Neutral pairs, 1 face aboveand 1 face below a central fixation position. Followingthe faces display, a target probe appeared in 1 of thelocations vacated by the faces, and remained onthe screen until response. The target-probe consistedof 2 letters, either the letter “E” or the letter “F.” Par-ticipants were required to determine which letterappeared on the screen by pressing prespecified but-tons on the computer mouse using their dominanthand. Participants were told that it was important thatthey perform the task as quickly as possible withoutcompromising accuracy. Disgust faces were equallylikely to appear on the top or bottom. The face stimuliwere split into 2 sets, set A and set B, each consisting of6 faces (3 male).

Pre- and Posttreatment Assessments. In the pre-treatment assessment, participants were randomlyassigned to complete 160 dot–probe trials of either setA or B. A total of 128 trials (80% of trials) consisted ofDisgust–Neutral face pairs, with equal proportions ofthe target probes appearing at the location of thedisgust face (“congruent” trials) and the neutral face(“incongruent” trials). Thirty-two trials (20% of trials)consisted of Neutral–Neutral face pairs. In the post-treatment assessment, participants completed 320 tri-als with the same proportion of trial types as in thepretreatment assessment. For posttreatment assess-ment, the task used 160 trials of the same face stimulusset used in the pretest and an additional 160 trials withthe alternate set. Presentation of the stimuli of the 2sets (A and B) was intermixed. The use of trials withnew faces allowed testing regardless of whethertraining generalized to new faces not used in pre-assessment and in training.

Attention Bias Modification and Placebo Training.Training with the dot–probe task was delivered toparticipants in the ABMT groups during the CBT ses-sions. Specifically, in the ABMT þ CBT condition,participants were presented with the same 128Disgust–Neutral face pairs and 32 Neutral–Neutralface pairs as in the pretreatment session. However, inthe Disgust–Neutral trials, the target-letters alwaysappeared at the location of the neutral face (“incon-gruent” trials), thereby inducing a contingency be-tween target location and face valence. In the ABMTplacebo þ CBT condition, participants were presentedwith the exact same stimuli, but with the target probesappearing with equal probabilities at the locations ofthe disgust and the neutral face (50% “congruent” and50% “incongruent” trials). The same set of images as in

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the pretreatment assessment was used for the ABMTand placebo training.

CBT ProcedureAll treatments were delivered in the Child AnxietyClinic at Schneider Children’s Medical Center, Israelfrom October 2010 to July 2012. CBT involved 1650-minute sessions, based on the Coping Cat pro-gram.20,21 This protocol targets the physiological,cognitive, and behavioral aspects of anxiety, teachingchildren to recognize signs of anxiety and to imple-ment strategies to better cope with its debilitatingchallenges. The Coping Cat protocol was develop-mentally adapted to better fit patients younger than 9years based on suggestions provided by its authors.22

Early stages of treatment focus on improving affec-tive awareness, psycho-education, somatic manage-ment, and cognitive restructuring of maladaptivethoughts. Exposure to feared situations was graduallyconducted both within session and outside the clinicalcontext. Experienced psychologists trained in theCoping Cat protocol delivered the treatment; psy-chologists were supervised in a group setting through90-minute weekly meetings during which detailed casepresentations were discussed and treatment progres-sion was monitored.

ProcedureThe study was approved by the Ethic committee ofSchneider Children’s Medical Center and the IsraeliAdministration of Health. Participants and their par-ents were asked to participate in a study that examinedthe use of a computer task for treating anxiety. Theywere told that this computer task was part of thetherapy session and was to be delivered by the thera-pist. Furthermore, they were told that this task hadbeen examined in previous studies and that it had beenfound to be beneficial for some anxious adults andyouth. Participants were told that some anxiousindividuals show a tendency to focus on minor threatsin the environment and that this computer task wasdesigned to help them change this tendency. Finally,participants were told that they would be randomlyassigned to 1 of the 3 treatment groups and that theywere free to stop participation in the study at any time,and, if they choose to do so, it would have no effect oncompleting the CBT treatment. Parents provided writ-ten consent and children provided their assent.

Baseline assessments involved the dot–probe task,ADIS interview, and questionnaires, completed inapproximately 90 minutes, after which participants wererandomly assigned to 1 of 3 treatment conditions:ABMT þ CBT, ABMT placebo þ CBT, or CBT-alone. Inthe active and placebo ABMT conditions, therapists usedtheir clinical judgment to select the time for dot–probetraining within the 50-minute CBT session, such thatcontact time with therapists was equal in all 3 conditions.

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Post-treatment assessment took place 2 weeks after thelast CBT session. All study personnel and all researchparticipants were blind to participants’ training condi-tion. A Consolidated Standards Of Reporting Trials(CONSORT) diagram illustrating the flow of participantsthrough each stage of the study is shown in Figure 1.

Participants were not paid to participate in thestudy. Because the study was conducted in a publichospital’s anxiety clinic and because all childrenreceived CBT, a treatment known to be effective,patients had to pay a small amount to cover treatmentexpenses. However, this payment for treatment wassignificantly subsidized by mandatory public healthinsurance bills. In addition, the pre- and post-assessments were implemented as an integral part ofthe treatment plan in the clinic and were given to allparticipants free of charge.

Data AnalysisBaseline characteristics among the 3 randomized treat-ment groups were compared using c2 statistics and an-alyses of variance (ANOVAs). Three dependent variableswere used to examine differences in treatment efficacyacross the 3 groups. Two primary outcome measureswere examined, based on rating by clinicians blind toparticipants’ group assignment. The 2 measurescomprised the average number of anxiety symptomcounts reported by parents and children on the ADIS,and the averaged symptom severity scale scores ondifferent ADIS items. A secondary outcome was totalSCARED score, computed as the mean of child andparent SCARED total scores. Each of these 3 measures

FIGURE 1 Consolidated Standards Of Reporting Trials (CObehavioral therapy.

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was submitted to a separate analysis of variance(ANOVA), with Time (pretreatment, posttreatment) as awithin-subject factor and Condition (ABMT þ CBT,ABMT Placeboþ CBT, CBT-alone) as a between-subjectsfactor.

Attention bias scores were computed as the differ-ence score between reaction time in congruent trialsand reaction time in incongruent trials. Only correcttrials with reaction time in the range of 150 to 1500milliseconds were included in the analysis. Reactiontime less than 150 milliseconds could reflect a mererandom finger press not associated with the stimuli,whereas reaction times longer than 1500 millisecondscould either tap into higher cognitive processesinvolving more awareness or simply indicate processesirrelevant to the task.1,6,9 A z-score for each trial withineach of 3 possible trial types (neutral–threat congruent,neutral–threat incongruent, neutral–neutral) werecomputed, and trials with z-scores greater than j2.5jwere removed. To test the effect of attention training,attention bias scores before and after treatment weresubmitted to an ANOVA, with Time (pretreatment,posttreatment) as a within-subject factor and Condition(ABMT þ CBT, ABMT Placebo þ CBT, CBT-alone) as abetween-subjects factor. Pearson correlations wereused to test for possible associations among continuousmeasures.

Intent-to-Treat Analyses. Similar ANOVAs wereperformed using the last observation carried forwardmethod, whereby participants’ pretreatment assess-ment data were entered as their posttreatment data hadthey failed to complete the study. These analyses

NSORT) diagram of study design. Note: CBT ¼ cognitive

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included 3 participants in the ABMT group, 3 partici-pants in the ABM placebo group, and 2 participantsin the CBT-alone group who dropped out beforecompletion. All statistical significance thresholds wereset to a ¼ 0.05.

RESULTSSample CharacteristicsSample characteristics at baseline by treatmentgroup are provided in Tables 1 and 2. No groupdifferences in demographic, clinical, or attentionvariables emerged (all p > 0.30). In addition, nogroup differences in number of training sessionswas noted between the ABMT group (mean ¼8.00, SD ¼ 3.38, range ¼ 4–13) and the ABMTplacebo training group (mean ¼ 8.14, SD ¼ 3.15,range ¼ 4–15; t[35] ¼ �.13, p > 0.90). Finally, nocorrelation was found between participant ageand accuracy levels in the dot–probe task.

TABLE 2 Clinical Variables Pre- and Posttreatment Among C

ABMT n ¼ 15 ABMT

ADISAnxiety Dx, %Pretreatment 100Posttreatment 33Symptom Frequency, m (SD)Pre-treatment 8.31 (3.61)Posttreatment 3.13 (3.73)Symptom Severity, m (SD)Pretreatment 7.13 (0.71)Posttreatment 2.55 (2.80)

SCARED, m (SD)Pretreatment 33.64 (15.17) 2Posttreatment 22.63 (11.47) 2

Attention Bias, m (SD)Accuracy ThreatPretreatment 0.92 (0.05)Posttreatment 0.94 (0.05)Accuracy NeutralPretreatment 0.93 (0.05)Posttreatment 0.95 (0.05)RT-ThreatPretreatment 811.80 (195.01) 80Posttreatment 753.40 (200.63) 70RT-NeutralPretreatment 823.92 (211.23) 82Posttreatment 738.25 (209.78) 69Bias ScorePretreatment 12.11 (30.84) 2Posttreatment �15.15 (40.80) �1

Note: ABMT ¼ attention bias modification training; ACC ¼ accuracy rates; Atherapy; RT ¼ reaction time; SCARED ¼ Screen for Child Anxiety Related E*p < .05; **p < .01.

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Between-Group Differences After Treatment:Primary OutcomesSymptom Frequency. The ANOVA on symptomfrequency yielded a significant group-by-timeinteraction effect (F2,42 ¼ 4.05, p ¼ .025, partialh2 ¼ 0.16) (Table 2 and Figure 2A). Follow-upcontrasts revealed significant reductions in theaverage number of anxiety symptom counts aftertreatment in the ABMT þ CBT group, t(13) ¼5.22, p < .001 and the ABMT placebo þ CBTconditions, t(16) ¼ 6.27, p < .001, but only a trendin the CBT-alone group t(13) ¼ 2.01, p ¼ .06.

Symptom Severity. The ANOVA on symptomseverity also revealed a significant group-by-timeinteraction (F2,40 ¼ 3.66, p ¼ .035, partial h2 ¼0.155) (Table 2 and Figure 2B). However, unlikefor symptom frequency, a significant reduction insymptom severity was noted across all 3 groups:ABMT þ CBT, t(13) ¼ 5.57, p < .001; ABMTplacebo þ CBT, t(15) ¼ 9.91, p < .001; and the

ompleters Across the 3 Treatment Groups

-Placebo n ¼ 22 CBT Alone n ¼ 18 Statistics

100 10036 72 c2

(2) ¼ 6.72*

6.80 (3.31) 7.19 (2.91) F2,48 ¼ 0.6651.20 (1.33) 5.14 (4.32) F2,48 ¼ 4.66*

6.24 (1.43) 6.64 (1.25) F2,47 ¼ 0.9631.13 (1.30) 4.05 (2.40) F2,47 ¼ 5.61**

9.73 (9.10) 34.50 (14.18) F2,52 ¼ 0.7285.84 (14.06) 36.11 (17.93) F2,52 ¼ 3.88*

0.90 (0.10) 0.94 (0.04)0.89 (0.12) 0.95 (0.03)

0.91 (0.09) 0.94 (0.08)0.91 (0.08) 0.96 (0.04)

0.80 (201.48) 863.09 (263.33)7.09 (224.59) 753.25 (237.99)

2.41 (211.47) 885.24 (244.41)3.70 (245.83) 749.95 (248.53)

1.61 (65.35) 22.15 (51.43) F2,52 ¼ 0.1833.39 (48.13) �3.30 (56.17) F2,52 ¼ 0.293

DIS ¼ Anxiety Disorders Interview Schedule; CBT ¼ cognitive behavioralmotional Disorders, mean score of parent and child SCARED.

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FIGURE 2 (A) Number of anxiety symptoms before and after treatment across the 3 treatment groups; (B) severity ofanxiety symptoms before and after treatment across the 3 treatment groups. Note: CBT ¼ cognitive behavioral therapy.

A

B

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CBT-alone, t(12) ¼ 3.60, p ¼ .004, with a largereffect in the 2 ABMT groups than in the CBT-alone group, t(40) ¼ 2.62, p ¼ .012.

To control for possible age effect, the sameanalyses were conducted with age of participantsas a covariate. The same results were observedfor both the frequency and the severity ofsymptoms.

Between-Group Differences After Treatment:Secondary OutcomesSCARED. The ANOVA on averaged SCAREDtotal scores also yielded a significant time-by-group interaction (F2,52 ¼ 5.52, p ¼ .007, partialh2 ¼ 0.175) (Table 2 and Figure 3). Follow-up contrasts indicated a significant reductionin symptoms only in the ABMT þ CBT group(t[14] ¼ 3.13, p ¼ .007), with a trend in the ABMT

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placebo þ CBT [t(21) ¼ 1.99, p ¼ .06], butno significant change in the CBT-alone group(t[17] ¼ �0.75, p > .48).

Finally, at the posttreatment assessment, the 3groups differed in terms of their rates of an on-going anxiety disorder (Table 2). No differencesbetween the ABMT and the ABMT placebogroups were noted (c2

(1) ¼ 0.03, p > .05). How-ever, both the ABMT (c2

(1) ¼ 4.99, p ¼ .025) andthe ABMT placebo groups (c2

(1) ¼ 5.11, p ¼ .024)differed from the CBT-alone group.

Intent-to-Treat AnalysisThe intent-to-treat analysis results and theresults obtained from the completers analysesreported thus far were similar. The ANOVAon symptom frequency yielded a significantgroup-by-time interaction effect (F2,44 ¼ 3.24,

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FIGURE 3 Screen for Child Anxiety Related Emotional Disorders (SCARED) scores before and after treatment acrossthe 3 treatment groups. Note: CBT ¼ cognitive behavioral therapy.

SHECHNER et al.

p ¼ .049, partial h2 ¼ 0.13). Follow-up contrastsrevealed significant reductions in the averagenumber of anxiety symptom counts after treat-ment in the ABMT þ CBT group (t[14] ¼ 4.90,p < .001) and the ABMT placebo þ CBT con-ditions (t[17] ¼ 5.89, p < .001), but only a trendin the CBT-alone group (t[13] ¼ 2.06, p ¼ .06).The ANOVA for symptom severity revealeda trend for the group-by-time interaction effect(F2,42 ¼ 2.57, p ¼ .088, partial h2 ¼ 0.11).A significant reduction in symptom severitywas noted across all 3 groups (ABMT þ CBT,t[14] ¼ 5.18, p < .001; ABMT placebo þ CBT,t[16] ¼ 8.43, p < .001; and the CBT-alone, t[12] ¼3.56, p ¼ .004). The ANOVA on averagedSCARED total scores also yielded a significanttime-by-group interaction (F2,59 ¼ 5.16, p ¼ .009,partial h2 ¼ 0.15. Follow-up contrasts indicateda significant reduction in symptoms only in theABMT þ CBT group (t[16] ¼ 3.02, p ¼ .008), butno significant changes in the ABMT placebo þCBT, (t[24] ¼ 1.67, p > .10) or in the CBT-alonegroups (t[19] ¼ �0.72, p > .48).

Between-Group Differences in Attention Bias ScoresAfter TreatmentThe ANOVA on attention bias scores yielded asignificant main effect of time (F1,52 ¼ 7.06, p ¼.010, partial h2 ¼ 0.12), but no interaction effectwith treatment condition (Table 2). Participants inall 3 groups started with mean attention biastoward threat (mean ¼ 19.20, SD ¼ 52.53), andthis bias decreased in a similar fashion amongall 3 groups after treatment (mean ¼ �10.56,

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SD ¼ 48.50). No correlation was found betweenparticipants’ age and accuracy levels on the dot–probe task. No correlations were found betweenattention bias scores and baseline anxiety symp-toms. Furthermore, no significant correlationswere found between pre- and posttreatmentattention bias change scores and anxietysymptoms.

The ANOVA on attention bias scores that werecomputed using the novel set of stimuli at post-treatment yielded similar results. A significantmain effect of time (F1,52 ¼ 9.09, p ¼ .004, partialh2 ¼ 0.15), but no interaction effect with treat-ment condition. Participants in all 3 groups star-ted with mean attention bias toward threat(mean ¼ 19.20, SD ¼ 52.53), and this biasdecreased in a similar fashion among all 3 groupsafter treatment (mean ¼ �15.58, SD ¼ 58.52).

DISCUSSIONThis study is the first RCT to examine the aug-menting effects of threat-based ABMT on thewidely used CBT protocol (Coping Cat) for pe-diatric anxiety. Three main findings emerged.First, both the active and placebo ABMT groupsshowed greater reductions in clinician-ratedanxiety symptoms than the CBT-alone group.Second, group differences also emerged in self/parent-rated anxiety symptoms. However, un-like for clinician-rated anxiety, only the activeABMT group and neither of the other 2 groupsshowed a significant reduction on this self-/parent-rated measure. Finally, all 3 groupsshowed a shift in attention from a bias toward

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threat before treatment to a bias away fromthreat at posttreatment with no between-groupdifferences.

Findings in the current study are bothsimilar and different from findings in 4 otherthreat-related ABMT RCT studies in pediatricanxiety. As in 2 prior studies that used ABMTas a stand-alone therapy for pediatric anxiety,between-group difference emerged here forclinician-rated symptoms.6,7 However, unlikethese prior studies, in the current study bothgroups receiving a dot–probe task showedgreater treatment benefits compared to the CBT-alone group. Thus, the current findings differfrom 2 prior studies of ABMT delivered as astand-alone treatment, which found differencesbetween active and placebo ABMT. Interestingly,a recent study trained severely anxious adoles-cents in addition to a standard care at a residen-tial anxiety treatment facility.10 Similar to ourresults, both the active and the placebo ABMTconditions showed improvement as indicated byreductions on SCARED scores. Yet, unlike ourresults, the active ABMT group experienced asignificantly greater decrease in anxiety symp-toms than the ABMT placebo group. However,the study by Riemann et al. did not compareABMT to a CBT-alone group. Moreover, althoughthe standard care treatment was CBT oriented, itdid not follow a structured CBT protocol. Of note,a fourth ABMT study trained clinically anxiouschildren to attend to happy faces; this study,much like the current one, found similar benefi-cial effects on self-report (SCARED) in the activeand placebo forms of happy-face–based ABMT,added to CBT.9 Taken together, when combinedwith the current findings, all 5 studies of ABMTin pediatric anxiety report some evidence ofclinical benefit. Nevertheless, this benefit appearsto vary as a function of outcome measure, studydesign, and sample size.

ABMT is thought to reduce anxiety throughspecific effects on threat bias patterns. However,aspects of the current study raise questions aboutthe mechanism through which ABMT achievesthese anxiety-reduction effects. In the currentstudy, no group differences in attention biasmanifested after treatment, and mean attentionbias scores showed reductions from pre- toposttreatment in all 3 treatment groups. Thesechanges in bias score after treatment wereapparent not only when posttreatment bias scorewas measured using the same set of stimuli as inpretreatment but also when a new set of stimuli

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was used, indicating the generalization of thiseffect beyond the specific stimuli used intraining. Changes in threat-related attentionbiases after stand-alone CBT were previouslyreported by others,23,24 and were also associatedwith better CBT outcomes.25,26 Thus, CBT mayreduce threat biases to a considerable degree onits own. In addition, some studies in anxiousadults demonstrate that training away fromthreat reduced threat-related attentional biasonly temporarily.27 Similar to the method usedin the current study, no differences in attentionbias were noted between the training and thecontrol group 1 week after training completion,and both groups reported reduction in anxietysymptoms. This CBT-induced change couldcreate a floor effect that might obscure the ca-pacity to detect any additional effect on attentionbias between the group that received activeABMT training and the 2 other groups, all ofwhich received the same CBT treatment. Lack ofgroup differences in the current study could alsoreflect other limitations. For example, because ofparticipant burden, the timing of posttreatmentassessments varied, occurring anywhere from0 to 2 weeks after the last CBT session. Thisvariability could further reduce the sensitivity ofthe dot–probe task, which exhibits only modestreliability even under the best circumstances.9 Inaddition, although no differences in number ofABMT sessions were found between the ABMT-active and the ABMT-placebo groups, the largerange and the variability in number of ABMTsessions across participants could have influ-enced the current results. In particular, becauseoverall exposure to ABMT differed in the currentstudy, relative to other studies, this could influ-ence attempts to compare findings across studies.Finally, unlike previous studies (e.g., that ofEldar et al.6), we did not use pretreatment threatbias score as an inclusion criterion. Regardless,the current pattern of results could arise fromvarious mechanisms, each producing reductionsin anxiety symptoms, beyond a direct effect fromABMT on attention bias. It is important toconsider such possibilities.

One possibility would be for clinical benefitsfrom dot–probe training to emerge througheffects on attention that are not measurablewith sufficient sensitivity based on RT data.Available data suggest that neural or eye-movement indices may be more sensitive thanRT measures.9,28 Another possibility is thatenhanced clinical effects in the 2 ABMT groups

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reflect general placebo-type expectancy effectsin these groups, over the CBT-alone group.Given that no between-groups differences inattention patterns were detected, the reductionin anxiety captured by the clinician-ratedmeasures support such a possibility. Althoughplausible, this possibility is less consistent withthe findings for the self/parent-reportSCARED. Specifically, if patients’ expectancyof benefit is the major contributor to theobserved clinical effects, one would predict thatsuch effects would manifest more strongly inchildren’s and parents’ ratings, than in clini-cians’ ratings. The opposite pattern manifestedhere. A third possibility is for clinical benefit ofABMT to accrue from mechanisms independentof changes in attention bias. Nevertheless, sucha conclusion is inconsistent with findings inother ABMT studies reporting an associationbetween dot–probe performance and clinicaloutcome.3 Fourth, ABMT, much like otherforms of computer training, could produceincreased proficiency in diverse forms ofattention control and flexibility. These nonspe-cific effects could reduce anxiety, accountingfor the observed differences between the CBT-alone and the 2 ABMT groups. Finally, themere exposure to aversive faces included inboth the ABMT tasks may contribute to anxietyreduction.6 As with conclusions on the overallrobustness of the ABM’s clinical effect, defini-tive conclusions on potential mechanism ofchange will have to await results from futurestudies designed to evaluate the plausibility ofeach mechanism.

Other aspects of the current study areimportant to consider in light of other ABMTwork. For example, CBT effects in the currentstudy were rather weak (w70% of the childrenstill met anxiety criteria after treatment), rela-tive to those reported in prior studies usingsimilar CBT procedures (w40% of chil-dren).14,20,29 This effect is surprising, given thatthe CBT delivered in the current study followeda standardized 16-session protocol (“CopingCat”) and may reflect the state of affairs inpublic hospital–based child anxiety clinics.Furthermore, participants were randomlyassigned to 1 of the 3 groups, using the sameset of clinicians for all groups and providingidentical treatments in the 3 conditions. The factthat therapists were not completely blinded to

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the CBT-alone group, in which no computertask was delivered, could have had some de-gree of unintentional effect on the way in whichthey delivered CBT to the ABMT-training andplacebo groups compared to the CBT-alonegroup. The presence of such bias, for example,could account for some findings where the 2ABMT groups both exhibited greater improve-ments than the CBT-alone group, although itcannot account for the other differences thatwere observed for the 2 ABMT groups. Never-theless, the current study was primarilydesigned to examine the effects of ABMT, andmonitoring the consistency of CBT imple-mentation across the 3 groups was not appliedwith the same level of care as in prior researchwith the primary goal of examining CBT effi-cacy. Thus, undetected differences in CBT pro-cedures used in the current study, compared toother studies, also could explain the relativelylow response rate in the current study. Inaddition, because of technical difficulties inrunning the computerized dot–probe task andother demands of treatment, only about half ofthe therapeutic sessions actually includedABMT training or placebo. Similarly, the dot–probe task was delivered by therapists at anygiven time during the session, according totheir clinical judgment. Variability in deliverytime of the dot–probe across sessions andacross therapists could have some effect ontreatment outcomes. Finally, findings from thecurrent study should be considered in light ofthe relatively small groups that may contributeto low statistical power as well as the hetero-geneous groups of diagnoses that wereincluded here. Of note, although the nature of achild’s diagnosis did not moderate outcome inthe current study, small sample size also wouldhave limited the power on such tests of treat-ment moderation.

Despite the above-described limitations, re-sults from this RCT suggest that active andplacebo ABMT augments response to standardCBT. This study adds to the growing ABMTliterature, laying the grounds for future workthat should focus further on examining the mosteffective ABMT protocol and the most efficientway to implement these as augmenting treat-ments to CBT, and clarifying the cognitivemechanisms underlying the anxiolytic effectof ABMT. &

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Clinical Guidance

� Threat-related attention biases are implicated in theetiology and the maintenance of anxiety disorders.In recent years, a novel computer-based taskdesigned to implicitly train anxious patients to shiftattention from minor threats was found to be bene-ficial in reducing anxiety.

� This randomized controlled trial (RCT) examined theaugmenting effects of attention bias modificationtreatment on cognitive behavioral therapy (CBT) inclinically anxious youth.

� Findings from this study indicate that patients whoperformed a visual attention task as part of a CBTsession showed greater reductions in clinician-ratedanxiety symptoms than the CBT-alone group. Inaddition, a certain training protocol of this taskintended to train patients’ attention away from minorthreat was found to be particularly beneficial inreducing self-reported anxiety symptoms.

� The results of this study corroborate findings fromother recent studies demonstrating the potentialclinical gains associated with implicit attentiontraining in augmenting CBT for anxiety disorders.

AUGMENTING EFFECTS OF ABMT ON CBT

Accepted October 8, 2013.

Dr. Shechner is with the University of Haifa. Ms. Rimon-Chakir and Dr.Bar-Haim are with Tel-Aviv University. Dr. Britton is with the University ofMiami. Mr. Lotan and Dr. Apter are with Schneider Children MedicalCenter in Israel. Dr. Bliese is with Walter Reed Army Institute ofResearch. Dr. Pine is with the National Institute of Mental Health.

This study was partially supported by a grant from the Adler Center forResearch in Child Development and Psychopathology to Dr. Bar-Haimand by the National Institutes of Health intramural research program.

Disclosure: Drs. Shechner, Britton, Apter, Bliese, Pine, and Bar-Haim,and Ms. Rimon-Chakir and Mr. Lotan report no biomedical financialinterests or potential conflicts of interest.

Correspondence to Tomer Shechner, PhD, Psychology Department,University of Haifa, Mt Carmel, Haifa, Israel, 3498838; e-mail:[email protected]

0890-8567/$36.00/ª2014 American Academy of Child andAdolescent Psychiatryhttp://dx.doi.org/10.1016/j.jaac.2013.09.016

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