Research Review: attention bias modification (ABM): a novel treatment for anxiety disorders

12 Pages·2010·0.21 MB·English

JournalofChildPsychologyandPsychiatry51:8(2010),pp859–870 doi:10.1111/j.1469-7610.2010.02251.x
Research Review: attention bias modification
(ABM): a novel treatment for anxiety disorders
Yair Bar-Haim
DepartmentofPsychology,TelAvivUniversity,Israel
Attention bias modification (ABM) is a newly emerging therapy for anxiety disorders that is rooted in
current cognitive modelsof anxiety and inestablished experimental dataon threat-related attentional
biasesinanxiety.ThisreviewdescribestheevidenceindicatingthatABMhasthepotentialtobecomean
enhancing tool for current psychological and pharmacological treatments for anxiety or even a novel
standalone treatment. The review also outlines the gaps in need of bridging before ABM techniques
could be routinelyappliedand incorporatedinto standardtreatment protocols.
In our field of research and practice few things gen- describes the accumulating evidence highlighting
erate more excitement than a new treatment for a the potential of ABM for alleviating anxiety. Finally,
major psychopathology such as the anxiety disor- the review outlines the gaps in need of bridging
ders, for which the considerable treatment data before ABM techniques could be routinely applied
collectedthusfarleavesmuchroomforimprovement andincorporatedintostandardtreatmentprotocols.
in treatment efficacy (Insel, 2009; Pine, 2009).
Anxiety disorders occur in anywhere from 5–20% of
children (Bernstein, Borchardt, & Perwein, 1996) Cognitive theories of anxiety and attention
and about 18% of adults (Kessler, Chiu, Demler, & bias modification
Walters, 2005), inflicting considerable suffering and
Cognitive accounts of anxiety suggest that informa-
dysfunction. With remission rates in first line treat-
tion-processing biases play a central role in the eti-
ments (cognitive-behavior therapy, pharmacother-
ology and maintenance of anxiety disorders (Beck &
apy) standing at only about 50% (Ballenger, 2004;
Clark, 1997; Eysenck, 1992, 1997; Rapee & Heim-
Barlow,Gorman,Shear,&Woods,2000;Cartwright-
berg, 1997; Williams, Watts, MacLeod, & Mathews,
Hatton, Roberts, Chitsabesan, Fothergill, & Harring-
1997). Along with application of conditioning prin-
ton, 2004), it is imperative to continue refining
ciples derived from behavior learning theories (e.g.,
existing treatments and actively pursuing more effi-
Rachman,1991;Wolpe,1973,1978),suchcognitive
cacious ones. This is particularly relevant for pedi-
models laid fertile grounds for the development and
atric anxiety disorders for which barriers to
refinement of cognitive-behavioral therapies (CBT),
treatment (reviewed later in this paper) are higher
now considered established evidence-based treat-
thanthoseforadults.Giventhatchronicpatternsof
ments for anxiety disorders in both adults and chil-
clinicallysignificantanxietyanddepressiontypically
dren(A.C.Butler,Chapman,Forman,&Beck,2006;
emerge during childhood (Pine, Cohen, Gurley,
G. Butler, Fennell, Robson, & Gelder, 1991; Cham-
Brook, & Ma, 1998), and given the potential of early
bless & Gillis, 1993; Kendall, 1994; Kendall et al.,
intervention for disrupting such long-term cycles of
1997;Kendall,Hudson,Gosch,Flannery-Schroeder,
maladaptation,itisparticularlyimportanttodevelop
& Suveg, 2008; Kendall & SouthamGerow, 1996).
and test novel treatments for highly anxious
According to such models, processing is guided by
children.
schemas (cognitive frameworks or concepts) that
Against this backdrop, a novel attention bias
largely determine how information is attended to,
modification(ABM)treatmentforanxietyhasstarted
interpreted, and remembered. In anxious individu-
to emerge. This new theory-driven treatment stems
als,schemasarethoughttobebiasedtowardthreat.
fromestablishedexperimentaldataonthreat-related
The translation of such models into applicable CBT
attentional biases in anxiety (for a review see Bar-
protocolsfocusedprimarilyontraininginrelaxation
Haim, Lamy, Pergamin, Bakermans-Kranenburg, &
techniques, systematic and graded exposure to
vanIJzendoorn,2007),andutilizescomputer-based
threat as a vehicle promoting fear extinction, and
attention training protocols to implicitly modify
direct, explicit, and conscious challenging of nega-
biasedattentionalpatternsinanxiouspatients.This
tive interpretive and memory biases. Although cur-
review first localizes ABM treatments in the broader
rentcognitivemodelsofanxietyreadilyacknowledge
context of cognitive therapies for anxiety. It then
the involvement of early, automatic, and pre-
conscious attentional biases in the etiology and
Conflictofintereststatement:Noconflictsdeclared. maintenanceofanxietydisorders,andevidencefrom
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
PublishedbyBlackwellPublishing,9600GarsingtonRoad,OxfordOX42DQ,UKand350MainStreet,Malden,MA02148,USA
860 YairBar-Haim
both animal and human research indicates that a matic, and sometimes unconscious attentional bia-
major component of emotion in general and anxiety ses by ABM therapy. ABM techniques may prove
inparticularreflectsfunctionalaspectsofsub-corti- valuable to anxiety patients who do not respond to
calneuralcircuitsthatarenotavailabletoconscious currently available treatments and in particular for
thought (e.g., Delgado, Nearing, LeDoux, & Phelps, anxious children for whom compliance with elabo-
2008; LeDoux, 2000; Pine, 2007), lack of means to rateCBTprotocolsoftenprovesproblematic(Kendall
directly manipulate such biases and patterns of &Sugarman,1997),andforwhomparentsareoften
neural activation within the context of standard reluctant to consider pharmacological treatment. As
psychotherapy leaves the treatment of these biased willbediscussedlaterinthisreview,itremainstobe
cognitiveprocessesoutoftheCBTtoolbox. seen whether these novel ABM tools will be inte-
Recently, however, ABM treatment studies have grated into standard CBT protocols or will end up
started to emerge. At the heart of this novel and serving as standalone therapies.
promising approach lies the idea that the classic
cognitive tasks, which provided ample evidence for
specific attentional biases in both anxious children
The design of ABM protocols for anxiety
and adults (Bar-Haim et al., 2007; Mogg & Bradley,
1998), can be modified to implicitly manipulate Most ABM studies utilized variants of the dot-probe
attention biases and reduce anxiety. Such transla- task (MacLeod, Mathews, & Tata, 1986) to measure
tions of insights from cognitive neuroscience have and manipulate threat-related attention biases.
startedtogeneratenovelapproachestotreatmentfor Figure 1 describes a typical dot-probe trial. In this
a variety of psychopathologies. Relevant examples task,twostimuli,onethreat-relatedandoneneutral
emergeindyslexia,forwhichbehavioralremediation (typically words or pictures of faces with distinct
focused on auditory processing and oral language expressions of emotion), are shown briefly on each
training was found to improve reading performance trial, and their removal is followed by a small target
in children (Gabrieli, 2009; Temple et al., 2003). In probe in the location just occupied by one of the
the same vein, schizophrenic patients who received stimuli. Participants are required to discriminate as
implicit computerized auditory training showed sig- fast as possible between two variants of the probe
nificant gains in global cognition, verbal working (e.g., the letters F and E or the shapes ‘..’ and ‘:’)
memory, and verbal learning and memory (Fisher, without compromising accuracy. In the classic for-
Holland, Merzenich, & Vinogradov, 2009). Finally, mat of this task, designed to measure attention
children with attention deficit hyperactive disorder biases, targets appear with equal probability at the
(ADHD)whoreceivedcomputerizedworkingmemory location of threat and neutral stimuli. Thus,
training showed improved response inhibition, rea- response latencies provide a ‘snapshot’ of the dis-
soning,andworkingmemory,aswellasreductionin tribution of participants’ attention, with faster
parent-reported inattentive symptoms of ADHD rel- responsestoprobesevidentintheattendedlocation
ative to a control group receiving a sham training relative to the unattended location. Attention bias
program (Klingberg et al., 2005). towards threat is revealed when participants are
A specific example of how such techniques are faster to respond to probes that replace threat-
currently applied in treatment for anxiety disorders related stimuli rather than neutral stimuli. The
is provided in the next section. Note, however, that opposite pattern indicates avoidance of threat.
an important distinction should be made between In attention-training variants of the dot-probe
theteachingofanxiouspatientstoemploytop-down task,targetlocationissystematicallymanipulatedto
effortful attention control strategies to divert atten- increase the proportion of targets appearing at the
tion away from anxiety-provoking thoughts as is location of the intended training bias. For example,
sometimes applied in standard CBT or other cogni- in a training protocol intended to induce attentional
tive therapies (e.g., Wells, White, & Carter, 1997), bias away from threat and toward neutral stimuli,
and the direct but implicit targeting of early, auto- targetswouldappearmorefrequentlyatthelocation
Figure1 Sequence of events in adot-probetrial
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
ResearchReview:Attentionbiasmodification(ABM) 861
readily amenable to explicit/conscious cognitive
intervention and which are supported by fast-
responding neural circuitries (Eldar & Bar-Haim,
2010;Monketal.,2008;Pine,2007forareview).
TheprecursorsofABMapproachwereprovidedin
twostudies(reviewedinMathews&MacLeod,2002)
in which high trait-anxious students received a
number of dot-probe attention training sessions
(6000–7500 trials) designed to direct their attention
away from threat cues. These students reported
significant reductions in trait anxiety scores from
pre- to post-training. Over the past two years ABM
studies have taken an important step forward by
showing quite dramatic effects of attention training
on anxiety symptoms in anxious patients and in
sub-clinical populations (see Table 1 for a summary
of the extant ABM studies). These studies have
focused on generalized anxiety disorder (GAD) and
social phobia (SP) employing dot-probe training
protocols.Areadilyspottedlacunainthisresearchis
thelackofABMstudiesinpediatricanxietypatients,
Figure2 Schematic of Attention Bias Modification
to which I will refer later in this review.1
(ABM) study designed to evaluate treatment efficacy
and stressvulnerability
ABM for GAD
oftheneutralstimulusthanatthelocationofthreat.
Amir, Beard, Burns, and Bomyea (2009a) randomly
It is assumed that because attending to such con-
allocated patients with GAD to either an attentional
tingencies can assist in task performance, an
training condition designed to induce avoidance of
implicitlylearnedbiasawayfromthreatisgradually
threat words or to an attentional control condition.
induced with a systematic repetition of tens or
This dot-probe training entailed 160 trials of threat-
hundreds of trials. Effects of the training procedure
neutralwordpairspersession,administeredineight
on anxiety symptoms can be measured immediately
sessions across a four-week period. Following
upon completion of the training protocol, whereas
training 58% of the patients in the attentional
effectsofattentiontrainingonvulnerabilitytostress
training condition no longer met DSM-IV diagnostic
can be measured if participants are exposed to a
criteria for GAD compared to only 17% of the
stressor following the attention training protocol
patients in the control condition. The clinical effi-
(Figure 2).
cacy of the attentional training procedure was
Because only one published study on attention
further supported by improvements on a range
training for anxiety used a paradigm different than
of clinician-delivered and self-report measures of
the dot-probe task (Dandeneau, Baldwin, Baccus,
anxiety.Similarfindingswererecordedinastudyof
Sakellaropoulo, & Pruessner, 2007), the rest of this
undergraduate students (Hazen, Vasey, & Schmidt,
review will focus on dot-probe-based attention-
2009)whoreportedstableandseverelevelsofworry
training studies. This by no means implies that the
(most of which met DSM-IV diagnostic criteria for
dot-probe task is the most effective or most relevant
GAD). In this study, participants were randomly as-
paradigm. In fact, the anxiolytic effects demon-
signed to receive five sessions of either attentional
strated by Dandeneau et al. (2007), who used a
training to avoid threat words or a control placebo-
visualsearchtasktorepeatedlytrainparticipantsto
training. Compared to participants in the control
locate a single smiling face in a matrix of frowning
condition, the participants who received the active
faces,arequiteimpressiveandequalthoseobtained
training program produced significant reductions in
with the dot-probe task.
both threat bias and anxiety-depression symptoms.
ABM attenuates clinical symptoms of anxiety
ABM for social anxiety
Basic research on threat-related attentional biases
Three dot-probe studies using neutral and disgust
hasbeenprimarilymotivatedbythehopethatitwould
faces as cue stimuli applied attentional training
lead to new and more efficient psychotherapeutic
protocols to reduce social anxiety. Schmidt, Richey,
interventions for emotional disorders (MacLeod,
Buckner, and Timpano (2009) randomly assigned
Koster, & Fox, 2009; Mobini & Grant, 2007; Pine,
Helfinstein,Bar-Haim,Nelson,&Fox,2009).Ofpar-
ticularinterestforABMtherapyareearlyattentional 1The author is aware of three attention training studies in
processes that have been typically considered not anxiouschildrenbeingcurrentlyconducted.
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
862 YairBar-Haim
Table1 Alistoftheextantattentionbiasmodification(ABM)studies
Total#of
Threat Attention #of critical
Study Population Paradigm Stimuli Content Redirection Sessions Trials
Amiretal.(2008) SociallyAnxiousStudents Dot-Probe Faces Disgust Neutral 1 128
Amiretal.(2009a) GADPatients Dot-Probe Words Negative Neutral 8 1024
Amiretal.(2009b) SPPatients Dot-Probe Faces Disgust Neutral 8 1024
Dandeneauetal. NonselectedStudents VisualSearch Faces Rejecting Happy 1/5 112/560
(2007)
Eldaretal.(2008) NonanxiousChildren Dot-Probe Faces Angry Neutral 2 672
andThreat
Eldar&Bar-Haim HighTrait-Anxious Dot-Probe Faces Angry Neutral 1 480
(2010) Students
Harris&Menzies NonselectedStudents Dot-Probe Words Spider Neutral 1 40
(1998) andThreat
Hazenetal.(2009) SeverWorryStudents Dot-Probe Words Negative Neutral 5 640
Klumpp&Amir SociallyAnxiousStudents Dot-Probe Faces Disgust Neutral 1 128
(2010) andThreat
Lietal.(2008) SociallyAnxiousStudents Dot-Probe Faces Angry Happy 7 3360
MacLeodetal.(2002) NonanxiousAdults Dot-Probe Words Negative Neutral 1 576
andThreat
MacLeodetal.(2007) NonselectedAdults Dot-Probe Words Negative Neutral 1 288
andThreat
Mathews&MacLeod HighTrait-Anxious Dot-Probe Words Negative Neutral 8/10 6000/7500
(2002) Students
Schmidtetal.(2009) SPPatients Dot-Probe Faces Disgust Neutral 8 1024
Seeetal.(2009) NonselectedStudents Dot-Probe Words Negative Neutral 15 2880
patients with generalized SP to either a training Furthermore, blind raters judged the speeches of
condition designed to reduce vigilance for threat those in the attention training condition as better
(disgustfacialexpressions)ortoacontrolcondition. thanthoseinthecontrolcondition.
In this study patients received eight sessions across
four weeks, each incorporating 160 trials (128 criti-
ABM in nonanxious populations
caltrials).Aftertheintervention,72%ofthepatients
in the attentional training condition no longer met One of the most important theoretical and practical
diagnostic criteria for SP, compared to 11% of the questionsconcerningABMiswhetherattentionbias
patients in the control condition. At a follow-up toward threat is causally related to anxiety symp-
assessment four months later, 64% of the partici- toms. Proving causality is important because it
pants in the attentional training condition were constitutes the logical foundation for the mecha-
classifiedasremittedversusonly25%ofthoseinthe nisms by which ABM therapies work. Scientifically,
control condition. Using the same procedure in a this question can only be answered by experimen-
randomized,double-blindplacebo-controlledtrialin tally inducing a temporary bias toward threat and
a group of patients diagnosed with generalized SP, measuring its impact on anxiety levels. Although
Amir et al. (2009b) found that attention training temporary threat bias-induction may be ethically
away from disgust faces facilitated attention disen- justified for nonanxious participants, it might be
gagement from threat and reduced clinician- and more difficult to defend for clinically anxious
self-reportedsymptomsofsocialanxietyrelativetoa patients (but see Klumpp & Amir, 2010).
placebo training condition. The percentage of par- Tomyknowledgethereareonlytwostudies,onein
ticipants no longer meeting DSM-IV criteria for gen- adults and one in children, that directly tested for
eralized SP post treatment was 50% in the active causalityinacontrolledexperimentalABMdesign.In
traininggroupand14%intheplacebocontrolgroup. a seminal report, MacLeod, Rutherford, Campbell,
Symptom reduction in the active training group was Ebsworthy,andHolker(2002)demonstratedthatitis
maintained at four-month follow-up assessment. possible to modify patterns of attention to threat in
Finally, using a similar design, Amir, Weber, Beard, nonanxiousparticipantsandthatsuchchangesalter
Bomyea,andTaylor(2008)exposedsociallyanxious affective responses to subsequent stress. In this
undergraduate students to a single dot-probe study,avariantofthedot-probetaskwasusedtotrain
session(128criticaltrials)ofeitherattentiontraining nonanxious participants either to adopt a biased
away from facial expressions of disgust or a control attentionalresponsetowardthreatwords(i.e.,probes
condition. Relativetoparticipantswhoreceivedcon- always appeared in the loci of threat) or to adopt an
trolplacebotraining,participantswhoweretrainedto attentionalbiasawayfromthreat(i.e.,probesalways
attend away from disgust faces showed significantly appearedinthelociofneutralwords).MacLeodetal.
lessattentionbiasaftertrainingaswellaslowerlevels (2002) found that these two groups of participants
ofanxietyinresponsetoapublic-speakingchallenge. developed differentially biased attention responses
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
ResearchReview:Attentionbiasmodification(ABM) 863
that were in accord with the assigned threat-target Summary
contingency. This differential attention bias did not
Theevidenceofclinicallyrelevanteffectsofattention
result in an immediate change in anxiety following
training in GAD and SP patients directly links the
training,perhapsduetothenonanxiousnatureofthe
research on therapeutics and the research on
participants who were specifically selected for this
attention bias. At the theoretical level, the extant
trait. However, attention modulation did lead to a
attentiontrainingstudiesprovidestrongsupportfor
group difference in anxiety vulnerability to a subse-
the hypothesis that modifying attentional biases
quentlyinducedstress.Whereasbothgroupsofpar-
toward threat causally reduces anxiety symptoms.
ticipants responded to the stress manipulation with
At the practical level, these findings indicate that it
elevation in state anxiety, the magnitude of this ele-
may be possible to utilize attention training proce-
vationwassignificantlygreaterinthoseparticipants
duresclinically,eitherindependentlyorasaugmen-
who had been exposed to the attendance to threat
tation of already established treatments for anxiety.
condition. Eldar, Ricon, and Bar-Haim (2008) repli-
Despite its high prevalence, many individuals with
cated this finding in nonanxious 7–12-year-old chil-
anxiety disorders do not receive treatment. Addi-
dren using a dot-probe variant with naturalistic
tionally,manyindividualswhopresentfortreatment
pictures of angry and neutral facial expressions. In
respond poorly to it, do not respond at all, or drop
additiontogroupdifferencesinself-reportedanxiety
out of treatment (Kendall & Sugarman, 1997). Spe-
following stress induction, this study showed that
cifically for children and adolescents, computer-
relative to children who were trained to attend away
based training of attention may be more acceptable
fromthreat,childrentrainedtoattendtowardthreat
than traditional in-person therapy formats, and
showed a higher frequency of anxious behavior as
it may offer advantages by delivering systematic
coded from video tapes recorded during the stress
exposure to threat during which attention can be
episode.Bydemonstratingthatchildrenasyoungas
guided and controlled (Pine et al., 2009). Such
7 years of age are able to comply with repeated
computer-based attention retraining may act
attentiontrainingsessionsandthattrainingiseffec-
directly to reduce anxiety symptoms and could
tiveinmodulatingboththreatbiasandanxiety,this
augment the core-CBT feature of systematic expo-
study sets the stage for evaluating the clinical rele-
sure to threats. With CBT, patients attempt to use
vanceofABMforanxiouschildren.
cognitive control strategies to willfully alter their
ABMtechniquesmayalsobeusedasaprevention
attentional focus (see also Wells et al., 1997). With
measurereducinganxietyandstressvulnerabilityin
computerized ABM, patients can implicitly learn to
individuals who are bound to face stressful natu-
control attention in the absence of explicit instruc-
ralistic circumstances, which could range from mild
tions. Thus, combining CBT with ABM may simul-
(e.g., upcoming midterm exams) to severe (e.g., mil-
taneously target explicit and implicit processes
itary deployment to combat). This potential applica-
contributingtobiasedcognitiveprocessesinanxiety.
tion was demonstrated by See, MacLeod, and Bridle
Finally, the computer-based nature of ABM bears
(2009) who followed Singaporean students while
the potential to enhance dissemination of treatment
preparing to immigrate to Australia for tertiary edu-
both in the clinic and remotely, over the internet
cation–aneventconsideredhighlystressfulbythese
or via installation of simple software packages
students. Applying a dot-probe attention training
(Chu et al., 2004; MacLeod, Soong, Rutherford, &
schedule before migration, half of the participants
Campbell, 2007).
were randomly biased away from emotionally nega-
tivewordstimuli,andhalfreceivedaplacebocontrol
training not intended to change attention patterns.
Technical and theoretical considerations
Trainingreducedanxietyresponsestotheupcoming
naturalistic stressor of migration and reduced state The extant preliminary data suggest impressive effi-
anxiety scores collected upon arrival at the host cacy of ABM protocols for reducing anxiety symp-
country. toms.Thedataalsoraisesomeimportanttheoretical
These findings from normative samples provide considerations and a pressing need to identify the
crucial evidence in support of the hypothesis that most efficient parameters for intervention protocols.
threatbiasisacausalfactorinanxietybyconfirming Specifically, it remains undecided whether anxiety-
two pivotal assumptions of ABM research: a) atten- reducing effects are specific to threat-related atten-
tion patterns can be altered through training proce- tional training or reflect a more general attentional
dures using classic cognitive tasks; and b) biased controlprocess;whethertherearecontraindications
attentional responses to threat can exert a specific for ABM treatment; whether threat content, when
influence on the tendency to experience anxiety used in training, should be congruent with the typ-
when encountering stressors. This latter finding ical fears of the specific anxiety disorder being trea-
could be highly relevant for the use of ABM as a ted or represent a more general category; to what
preventive measure for upcoming and unavoidable classesofstimulishouldattentionberedirectedtoin
stressors as well as in the context of relapse pre- training? What subcomponents of attention should
vention and sustainment of therapeutic gains. be targeted by ABM? What is the optimal frequency
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
864 YairBar-Haim
of ABM treatment and how many training trials achieved through the training protocol, and is in
would yield the highest therapeutic gains? And, turnresponsibleforthenotedreductionsinanxiety.
should the contingencies being trained remain Although the behavioral response time data in this
implicit or should these be explicitly spelled out for study were largely inconclusive with regard to
patients?Scientificevidenceconcerningtheseissues attention training effects, consistent with an atten-
will play a central role in determining the faith of tional control hypothesis, both participants who
ABMprotocols asacceptabletreatments foranxiety, were trained to attend toward threat and partici-
and each of these issues will be discussed below. pants who were trained to attend away from threat
faces exhibited a relative decrease in anxiety during
a speech challenge compared to participants in a
Are anxiety-reducing effects of attention training
placebo control condition. No difference in anxiety
specific to enhanced threat avoidance?
scoresbetweenthetwoattentiontrainingconditions
Attention training protocols for anxious individuals was found in this moderately anxious sample.
rely theoretically on the premise that anxiety is Despite these preliminary data (Klumpp & Amir,
associated with a faster engagement of attention to 2010), the general attentional control hypothesis
threat stimuli and with a greater difficulty to disen- must wait for a more programmatic experimental
gageattentionfromthreatafterithasbeencaptured testing in clinical and sub-clinical populations. Per-
(Bar-Haim et al., 2007; Fox, Russo, Bowles, & Dut- hapsthefirststepinthisdirectionshouldbetesting
ton, 2001; Mogg & Bradley, 1998). Thus, attention the anxiety-reducing effects of an attention training
training away from threat in anxious individuals is protocol that utilizes non-affective cue stimuli
expected to reduce both the enhanced attention (e.g., geometric shapes). If simple attention control
capture by threat and the delayed attentional dis- enhancement is the anxiolytic component of this
engagement from threat. Specifically, if the anxiety- intervention then anxiety-reducing effect should be
reducing effects of attention training are consistent expected with attention training to non-affective
with these premises, it must be attention training stimuli.
away from threat that decreases anxiety symptoms
and anxious reactivity to stressors and not placebo
Who should be treated with ABM protocols?
or attention training conditions that are not specific
to threat avoidance. A meta-analysis found equivalent combined effect
In contrast, recent theory and research may be sizesofthreat-relatedbiasinclinicalandnonclinical
taken to suggest that cognitive biases in anxiety high trait anxious populations (Bar-Haim et al.,
reflect a more general cognitive deficit that may not 2007). This finding suggests that an official clinical
be specific to attentional threat processing (e.g., cutoff is of little significance with regard to biased
Bishop, 2009; Derakshan & Eysenck, 2009; Derry- attentional processes in anxious individuals, and
berry&Reed,2002;Eysenck,Derakshan,Santos,& that milder forms of anxiety are sufficient for trig-
Calvo, 2007; Wells et al., 1997). According to such gering the full potential of the bias. In addition,
views, the anxiety-reducing effects of attention despite the fact that threat-related attention bias is
training may be due to increase in general atten- reliably observed in anxious patients and partici-
tional control regardless of its valence-related pantsandnotinnonanxiousparticipants(Bar-Haim
directionality. For instance, attention training may etal.,2007),thiseffecthasonlybeenestablishedas
increaseattentionalcontrolviaenhancementoftop- a group-means difference and is not reported at the
down cognitive capacities that may in turn inhibit level of the individual subject. Careful inspection of
threat processing (e.g., Pessoa, 2009; Pessoa, several samples of clinically anxious children and
McKenna, Gutierrez, & Ungerleider, 2002). adultsindicatethatnotallanxiousindividualsshow
The extant attention training studies did not an attention bias toward threat. In fact, despite
include systematic testing of the general attentional showinghigherthreatbiasscores,thedistributionof
control hypothesis. However, Klumpp and Amir threatbiasinanxiouspatientsisrathernormal,with
(2010) studied a group of moderately socially anx- large numbers of individuals not showing the bias.
iousundergraduatestudents,and,inadditiontothe Takingthisunofficial(butnotdisputed)statisticinto
standard training away from threat and placebo consideration, an important question arises: name-
training conditions, included a third training condi- ly,shouldanxiouspatientswhoshow noevidenceof
tion in which participants were trained to attend an attention bias toward threat be treated with
toward threat. While implicitly training anxious attention training protocols?
individualstoattendtowardthreatseemssomewhat A few issues may be of interest to consider in this
counterintuitive given the vast data showing that respect. First, if ABM produces a general improve-
anxious individuals typically possess such threat ment in attentional control rather than specific
bias to begin with, this condition provides a pre- threat-related effects, and this improvement serves
liminary test of the hypothesis that perhaps as the anxiolytic agent of ABM, then training atten-
enhanced attentional control rather than more effi- tion away from threat should have a therapeutic
cient attentional disengagement from threat is effect on patients whether they show threat bias or
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
ResearchReview:Attentionbiasmodification(ABM) 865
not. Second, attention training procedures may of the stimuli such as words versus pictures. Word
servetoregulateandnormalizeattentionalbiasesin stimuli may be particularly useful in the case of
both directions (i.e., toward and away from threat). attention training protocols for disorders in which
This may be particularly relevant to social anxiety, anxiety is related to abstract threat themes (e.g.,
for which it has been shown that patients demon- GAD,PTSD)–suchabstractioncouldberepresented
strate both faster initial engagement with threat but more efficiently with written words. In contrast, for
also enhanced later avoidance of threat (e.g., Amir, specific phobias (e.g., spider phobia, social phobia),
Foa, & Coles, 1998). Finally, initial measurement of inwhichanxietyismorefocusedandrefined,theuse
threat bias may not represent the true tendency of of images may be more effective.
anxious individuals to be highly vigilant toward Utilization of threat stimuli that are specifically
threat. Specifically, several studies have shown that tailored for a particular disorder or the anxious
threat bias is suppressed and even reverses in anx- concernsofaparticularpatientindicatesagooddeal
ious individuals under conditions of threat (e.g., of common sense and rhymes well with clinical tra-
Amir et al., 1996; Constans, McCloskey, Vasterling, dition. However, personalized protocols introduce a
Brailey, & Mathews, 2004; Helfinstein, White, Bar- serious toll on ease of delivery, dissemination, and
Haim, & Fox, 2008; Mathews & Sebastian, 1993; costs of treatment. If attention training protocols
Mogg, Kentish, & Bradley, 1993). Thus, if a priori servetobalanceperturbationsinbasicandrelatively
biasistobecomeaconsiderationinprescribingABM hard-wiredmechanisms(Bar-Haimetal.,2007;Pine
treatment, some standard measurement of bias, et al., 2009), then it might be possible to achieve
preferably not taken during the stress of the first significanttherapeuticeffectswithattentiontraining
session of psychotherapy, should be delineated and protocols applying a standard set of stimuli.
tested. Furthermore, the stability and retest reli-
ability of threat-bias measurement will have to be Where should attention be directed? Once threat
carefully established. stimuliareselected,researchersandtherapistsmust
decide on the class of stimuli to which attention be
directed when training for disengagement from
Considerations related to stimuli selection
threat.Thevastmajorityofattentiontrainingstudies
Even if accumulating data will eventually indicate todatemanipulatedattentionbiasbyveeringitaway
thattrainingattentionawayfromthreatisakeyfactor from threat and onto a neutral stimuli (words or
inanxiety-reducingeffects,itwillremainimportantto pictures). Enhanced attention to neutral over threat
decide: a) what are the most effective and relevant materialmayrepresentarealistictherapeuticgoalin
threat stimuli that can be used in attention training which perturbed interplay between attention and
protocols;andb)whatarethemosteffectiveandrel- emotion in anxious individuals reaches a more neu-
evantstimulitoveerattentionto. tralbalance.Althoughthisapproachprovedefficient
invariousclinicaltrials(e.g.,Amiretal.,2009a;Amir
Specificity of threat stimuli. To date, attention et al., 2009b; Schmidt et al., 2009), it is not clear
training studies appear to have selected threat whether this training approach is indeed the most
stimuli that are conceptually relevant to the specific potent approach available. For example, there is
anxiety disorder being treated. In one case, stimuli evidence that anxious individuals also show biases
were idiosyncratically selected to represent the spe- anddeficitsintheprocessingofpositivestimuli(e.g.,
cificworriesofindividualpatients(Amiretal.,2009). Bradley, Hogg, White, Groom, & de Bono, 1999;
That is, before training, each patient was asked to Frenkel, Lamy, Algom, & Bar-Haim, 2008; Mansell,
ratetheemotionalvalenceofeachwordfromalarge Clark, Ehlers, & Chen, 1999), thus, conceptually,
list and the specific words that were rated as most attention could be trained away from threat and
negativebyaparticularparticipantwereusedasthe toward positive stimuli or even simply away from
threat stimuli in his or her dot-probe training task. neutralandtowardpositivestimuli.
SuchastrategymaybeparticularlyrelevanttoGAD Indeed, Wadlinger and Isaacowitz (2008) used a
in which there is a large variability in the nature of dot-probe task to train a nonselected group of
concernsforeachpatient.Attentiontrainingstudies undergraduate students to attend either toward
for SP (Amir et al., 2008; Schmidt et al., 2009) also positive or toward neutral words (happy–neutral
applied a disorder-specific approach in selecting displays). Eye-tracking revealed that participants
threat stimuli utilizing disgusted faces as threat. trained to attend to positive information looked sig-
Indeed,theprimaryconcernsofpatientswithSPare nificantlylessatstressfulnegativeimagespresented
in the realm of social evaluation andsocial rejection to them upon completion of the attentional training
(see Yoon & Zinbarg, 2007) and arguably disgust than their counterparts who were trained to attend
conveys a message of aversion or rejection (Rozin, toneutralstimuli.Thisfindingsuggeststhatpositive
Lowery, & Ebert, 1994). attention bias may be used to regulate attention
In addition to relevance of specific contents for patterns and thereby emotional response while
specific disorders, the selection of disorder-specific under stress. Li, Tan, Qian, and Liu (2008) took a
threatstimulimayalsorelatetomorebasicfeatures different training approach and used threat–happy
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
866 YairBar-Haim
face pairs in a dot-probe protocol designed to train attention orienting (Eldar & Bar-Haim, 2010). In-
sociallyanxiousstudentstoattendawayfromthreat deed, there is some indication that the threat-
and toward positive faces. Their task comprised a relatedbiasinclinicalanxietymightbedependentto
total of 480 critical trials per session, delivered on a greater extent on more elaborate processing of the
sevensuccessivedays.However,groupdifferencesin threat than on automatic pre-attentive processes
threat bias were unstable during the seven days of (Bar-Haim et al., 2007; see also McNally, 1995).
training and training effects did not last from one These findings may have practical implications for
session to the next. Furthermore, no significant interventions aiming at a systematic reduction of
changes in social anxiety scores as a function of threat bias in anxious patients. For instance, ABM
attention training condition were found. These protocols targeting the disengage component of
results may be taken to suggest that attention attention (e.g., using variants of the Posner’s spatial
training toward positive stimuli is less efficient in cueing task) may prove highly efficient. It is impor-
reducing anxiety than attention training away from tant, though, to make a distinction between the
threat and toward neutral stimuli. However, there attention training procedures discussed here and
are numerous factors that can explain the failure of attention training therapy (Wells, 2009). Wells and
this particular study to alter attention and anxiety colleagues’ approach deals primarily with diverting
patterns. Perhaps the most obvious reason is that attention away from self-focused negative thoughts.
each daily training session in this study ended with In contrast, ABM is focused on diverting attention
120 trials presenting the target probes with equal from minor threats in the environment, which may
probability at the locations of threat and happy be effective in many daily circumstances entailing
faces. This was done to obtain a measure of threat minimalobjectivethreat.Thereisalsoadifferencein
biaschangeforeachsession,butmighthaveundone its focus on targeting early attention processes vs.
the intended training effect at the end of each the more elaborate attention control processes tar-
session. This is an excellent example of a common geted by Wells’ procedures.
conflictinthislineofresearchbetweenthedesireto
closely monitor the impact of training on attention
The optimal structure of attention training
(manipulation check) and maximizing the potential
protocols
impact of training on anxiety symptoms. Another
reasonfortheunstableresultsintheLietal.(2008) There is considerable variability in the number of
study might have to do with the simultaneous sessions and the number of trials per session that
presentation of two emotional faces (happy and have been implemented in ABM protocols. This
threat). This presentation mode can influence the variability ranges from 7500 trials delivered over 10
affective tone and arousal levels of the training pro- sessions (Mathews & MacLeod, 2002) to a single
cedureasawhole,andintroduceanemotion-related session of 160 trials (Amir et al., 2008) that lasts
competition for attentional resources that might approximately 8 minutes. There is not enough
flatten the expected threat bias reduction effect. systematicdatayettodeterminetheoptimaldelivery
Tosummarizethissection,thereisarichvarietyof ofattentiontrainingprotocolsintermsofnumberof
stimuli that could be used in attention training trials and sessions. Our own experience suggests
protocolsforanxiouspopulations.Selectingtheright thatmostclinicallyanxiouschildrenwhoareatleast
combination of stimuli for specific patient popula- 8 yearsofageareabletocomplywithfive50-minute
tions can immensely impact the magnitude of treat- weekly dot-probe training sessions of 480 trials
ment effects and presents as a major area of much each. Clearly, however, shorter and fewer sessions
needed systematic exploration. could increase compliance and cost-effectiveness,
particularly in pediatric populations. To delineate
the parameters of the most efficacious protocol,
What is being trained with attention training
futurestudieswillhavetocloselyinspectbothgroup
protocols?
and individual learning curves within and across
There is an overwhelming dominance for use of the sessions.
dot-probe task in attention training studies. One of Additionally,thelastingeffectsoftrainingonboth
the criticisms of the dot probe task is that training- attention bias and anxiety should be measured in
relatedchangesinperformancecouldbetheresultof follow-up assessments. The most impressive evi-
either modulation in attentional engagement with dence to date suggest that for adults with SP, eight
threat, or of modulation of the ability to disengage sessions across four weeks, each incorporating 160
from it. Thus, it is not entirely clear what the atten- trials, produce strong therapeutic effects and con-
tion components being trained with dot-probe pro- siderable retention at four-month follow-up (Amir
tocols are. A recent dot-probe attention training et al., 2009b; Schmidt et al., 2009). It remains to be
study measuring event-related brain potentials seen whether attention training protocols could be
revealed that attention training away from threat shortened without ceding efficacy. Furthermore, as
modulatedanxiousparticipants’top-downprocesses discussed by MacLeod, Koster et al. (2009), the
of attention control rather than processes of early possibility that treatment results and outcome per-
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
ResearchReview:Attentionbiasmodification(ABM) 867
sistence might be enhanced by spreading rather effects. Even older children and adolescents commit
than crowding therapy sessions should be seriously significantly more errors than do adults on tasks
considered. The use of booster sessions, to periodi- similartothoseusedinABMprotocols,andanxious
cally reinstate the target patterns of attention train- children are prone to even lower accuracy, particu-
ing,mayalsoproveeffectiveinsustainingtheimpact larlyduringthefirstsessionsoftrainingwhenstress
of treatment. is still high. Therefore, close monitoring of accuracy
rates as training progresses is required. That being
Explicit vs. implicit training said, our experience also indicates that with a rea-
sonable number of slow self-paced training ((cid:2)40
All ABM studies so far have relied on participants’
trials), accuracy levels can be enhanced consider-
implicit (as opposed to explicit) learning of the in-
ably. Such preparation can sometimes make the
tendedcontingenciesbetweenthreatcuesandtarget
difference between successful application of ABM
location. Some studies have even added a certain
anddropout.Finally,attentiontrainingresearchand
amountofnon-contingenttrialsinordertoascertain
practice relies on relatively simple and, in many
that the intended cue-target contingencies do not
respects, visually dated and dull graphics. Current
become obvious (e.g., Amir et al., 2009). There are
technology could clearly provide new packaging of
reasons to believe that implicit learning might be
the computer tasks in a fashion that is more
more efficient in modifying threat bias, as it over-
appealing for children. This could considerably
comespotentialresistance andconscious avoidance
enhance compliance and clinical efficacy.
by gently but consistently challenging preexisting
biases. Indeed, a vast majority of participants who
Summary
received active training report that they believe they
had been assigned to the placebo control group Whileforthetimebeingmostoftheabovedelineated
(MacLeod,Mackintosh,&Vujic,2009).However,one dilemmas remain unresolved, they highlight the
may argue that explicit instruction to attend to a complexity and myriad parameters that could influ-
certain contingency may produce steeper learning ence the efficacy and cost-effectiveness of attention
curves and more prominent reductions in anxiety. training protocols, and the need for systematic
A recent study delivering the same dot-probe ABM manipulationoftheseattentiontrainingparameters.
task either with explicit instruction and explanation Inasense,attentiontrainingresearchandpracticeis
of the task’s contingencies, or with no such instruc- like a newlydiscovered oil field. Preliminary surveys
tions,indicatesthatthisisprobablynotthecase,and clearly indicate that a valuable resource has been
thatanxiety-relatedeffectsarestrongerintheimplicit identified,anditisnowtimetomoveonandsystem-
learning condition (MacLeod, Mackintosh et al., aticallydelineatethemostefficientwaystoextractit.
2009). However, a more detailed examination of the
effects of explicit vs. implicit learning on attention
biasmodulationandanxietysymptomsisrequired. Conclusion
Taken together, the extant evidence portrays a
Attention training for anxious children
promisingfutureforABMtreatmentsinanxiety.The
As mentioned above, except for Eldar et al.’s (2008) findingssuggestthatattentiontrainingisassociated
study, which applied an ABM protocol with non- with dramatic symptom reductions, including
anxious children, no other pediatric data has been remission of diagnoses and maintained positive
published. There are at least three clinical trials treatment effects four months after completing the
currently running with children but it will take a training. ABM may have several advantages over
whilebeforethesedatawillbereadyforpresentation. traditional psychosocial treatments because of ease
However,accumulatingexperienceandpriorstudies of delivery. Some of the specific advantages that
on attentional threat bias in children and adoles- make this treatment particularly appealing for
cents(Dalgleishetal.,1997;Monketal.,2008;Pine, children and adolescents include little need for
2007) indicate that there are several unique consid- therapist contact and that, relative to standard CBT
erations in applying attention training to this popu- or psychosocial protocols, it requires little effort or
lation. First, due to large variability in children’s motivationfrompatients.Furthermore,thecomputer-
readingproficiency,itisrecommendedthatattention based interface of attention training (with some
trainingprotocolsdesignedforchildrenusepictorial graphic and packaging upgrades) could bring
cues(e.g.,faces)ratherthanwords.Second,children therapy into the intuitive lifestyle of many children
younger than 7 years of age find the dot-probe and adolescents, improve compliance with treat-
task very difficult, which results in large number of ment, and open up the possibility of reaching
errorsandunreliableprocedures. Forolderchildren potential patients who do not have access to CBT
(8–12 years), shorter training periods, fewer trials, or medication, through web-based protocols and
andfrequentbreaksbetweentrainingblocksmaybe software installations (see also Kaltenthaler et al.,
necessary (Perez-Edgar & Bar-Haim, in press) and 2008). Finally, as pointed out by MacLeod, Koster,
this might have a negative impact on anxiolytic andFox(2009),becauseitcanbedeliveredremotely
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.
868 YairBar-Haim
and is relatively cheap, attention training seems ters of the attention training protocols, but also
particularly suitable for ongoing post-treatment use whether it will serve as a standalone treatment or
tominimizerelapseratesandenhancemaintenance become an established part of existing treatments.
of treatment gains. Viewed from a broader perspective, threat-related
A powerful asset of this rapidly evolving evidence- attentional biases could be characterized as a
based therapeutic approach is its rootedness in specific target for therapies in anxiety, much like
strong experimental cognitive science and cognitive specificcognitiveperturbationshavebeendelineated
neuroscience research. This rigorous scientific as targets for novel therapies in schizophrenia (see
tradition propels both theory and practice and it Buchanan et al., 2005; Green et al., 2004; Nuech-
is important that this thrust be integrated with a terlein et al., 2004). This approach has exerted an
sensitive clinical approach. It has been rightfully immense impact on how researchers and therapists
pointedout(MacLeod,Koster,andFox,2009;Pineet think about new treatments and could be readily
al., 2009) that it would not be reasonable to expect applied to current thinking about novel therapies
that ABM will always yieldtherapeutic gains for any such as ABM for anxiety disorders.
type of anxiety disorder. This must depend upon
whetheraspecificbiasdoesordoesnotplayacausal Acknowledgement
role in the etiology and maintenance of a particular
This research was supported by The Israel Science
anxietydisorderandonwhetherthetrainingprocess
Foundation (grant No. 964/08).
specificallyandeffectivelytargetsthisbias.Thenext
few years will witness a growing number of clinical
Correspondence to
trials that will serve to establish and perfect the
efficacy of attention training protocols across differ- Yair Bar-Haim, Department of Psychology, Tel Aviv
ent anxiety disorders in children and adults. These University, Israel; Email: [email protected]
trials will determine not only the technical parame-
Key points
• Anxiety disorders in both children and adults have been associated with threat-related attention biases.
• Recent studies have shown that threat biases can be modified via computer-based attention bias modi-
fication (ABM) protocols.
• Randomized control trials (RCTs) in adult patients have shown that ABM significantly reduces anxiety
symptoms,revealingtreatmenteffectsizesofsimilarmagnitudeasthosereportedinfirstlinetreatments
(CBT, SSRIs).
• RCTs in pediatric populations are needed to provide conclusive evidence for ABM treatment efficacy for
anxious children.
Ballenger, J.C. (2004). Remission rates in patients with
References
anxiety disorders treated with paroxetine. Journal of
Amir, N., Beard, C., Burns, M., & Bomyea, J. (2009a). ClinicalPsychiatry,65,1696–1707.
Attention modification programinindividuals withgen- Bar-Haim, Y., Lamy, D., Pergamin, L., Bakermans-Kran-
eralized anxiety disorder. Journal of Abnormal Psychol- enburg, M.J., & van IJzendoorn, M.H. (2007). Threat-
ogy,118,28–33. related attentional bias in anxious and nonanxious
Amir, N., Beard, C., Taylor, C.T., Klumpp, H., Elias, J., individuals: A meta-analytic study. Psychological Bulle-
Burns, M., etal. (2009b). Attention training in individ- tin,133,1–24.
uals with generalized social phobia: A randomized con- Barlow, D.H., Gorman, J.M., Shear, M.K., & Woods, S.W.
trolled trial. Journal of Consulting and Clinical (2000). Cognitive-behavioral therapy, imipramine, or
Psychology,77,961–973. their combination for panic disorder – a randomized
Amir, N., Foa, E.B., & Coles, M.E. (1998). Automatic controlled trial. Journal of the American Medical Associ-
activation and strategic avoidance of threat-relevant ation,283,2529–2536.
information in social phobia. Journal of Abnormal Psy- Beck, A.T., & Clark, D.A. (1997). An information process-
chology,107,285–290. ingmodelofanxiety:Automaticandstrategicprocesses.
Amir,N.,McNally,R.J.,Riemann,B.C.,Burns,J.,Lorenz, BehaviourResearchandTherapy,35,49–58.
M.,&Mullen,J.T.(1996).Suppressionoftheemotional Bernstein, G.A., Borchardt, C.M., & Perwein, A.R. (1996).
Stroop effect by increased anxiety in patients with Anxiety disorders in children and adolescents: A review
social phobia. Behaviour Research and Therapy, 34, ofthepast10years.JournaloftheAmericanAcademyof
945–948. ChildandAdolescentPsychiatry,35,1110–1119.
Amir,N.,Weber,G.,Beard,C.,Bomyea,J.,&Taylor,C.T. Bishop, S.J. (2009). Trait anxiety and impoverished
(2008).Theeffectofasingle-sessionattentionmodifica- prefrontalcontrol ofattention.NatureNeuroscience,12,
tionprogramonresponsetoapublic-speakingchallenge 92–98.
in socially anxious individuals. Journal of Abnormal Bradley,B.P.,Hogg,K.,White,J.,Groom,C.,&deBono,J.
Psychology,11,860–868. (1999). Attentional bias for emotional faces in general-
(cid:2)2010TheAuthor
Journalcompilation(cid:2)2010AssociationforChildandAdolescentMentalHealth.