Attentional bias modification in substitute-prescribed opiate users and control participants Matthew

133 Pages·2013·31.48 MB·English

Attentional bias modification in substitute-prescribed
opiate users and control participants
Matthew Charles
D.Clin.Psy. Thesis (Volume 1), 2013
University College London
UCL Doctoratein Clinical Psychology
Thesis declaration form
Iconfirm that thework presented in this thesis is myown. Whereinformation has
been derived from other sources, Iconfirm that this has been indicated inthethesis.
Signature:
Name: MatthewCharles
Date: 21 June2013
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Overview
This thesis investigatedbiases intheimplicit processingofsubstance-related
cues insubstanceusers. Part 1,aliterature review,assessedtheeffectiveness of
attempts tomodifysuch processes andthewider benefits ofdoingso. The 12studies
reviewed, addressingbetweenthem attentional bias, implicit attitudes andapproach
bias ineitheralcohol drinkers ortobaccosmokers, suggest that implicit processes are
readilymodifiable.However,the evidenceofwiderbenefit is less clear.Theclinical
implications andfutureresearchconsiderations arediscussed.
Part 2is anempirical paper,conductedjointlywithafellowtraineeclinical
psychologist,whichassessedtheeffects of attentional bias modification(ABM)in
opiatedependent andnon-substanceusingcontrol participants. Baselinedifferences
inattentional bias (AB)betweenthese groups wereassessed, as weretheeffects of
ABM onABand craving.Theroleoftreatment adherence(i.e. whetherornot an
individual was usingillicit opiates ontopoftheirprescribedsubstitute)was also
explored.Contrarytopredictions, therewerenobaseline groupdifferences inAB,
andABM hadnosignificant effects onABorcraving.However,treatment
adherencewas animportant factor, withdifferences foundbetweenopiate dependent
participants usingontop, not usingontopandcontrol participants onmeasures of
AB,cravingandpsychopathology.The clinical andresearchimplications ofthese
differences arediscussed.
Finally,Part 3,thecritical appraisal,provides reflections ontheentire
researchprocess.Some guidanceand recommendations arealso offeredtofuture
researchers coveringareas suchas thedifficulties inrecruitingfrom theseclinical
populations, andpossiblealternativeapproaches totheproblem ofbiases inimplicit
processes insubstanceuse.
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Tableof Contents
Thesis Declaration Form...........................................................................................2
Thesis Overview.........................................................................................................3
Tableof Contents.......................................................................................................4
Listof Tables..............................................................................................................7
Listof Figures.............................................................................................................8
Acknowledgements.....................................................................................................9
Part1:Literature Review........................................................................................10
1.0 Introduction......................................................................................................12
2.0Method.............................................................................................................16
2.1 Literaturesearch.......................................................................................16
2.2 Inclusioncriteria.......................................................................................16
2.3Studyselection.........................................................................................16
3.0Results..............................................................................................................17
3.1Attentional bias........................................................................................20
3.1.1Modifiedvisual probeparadigm...............................................20
3.1.1.1ABM inalcohol users ................................................21
3.1.1.2ABM intobacco smokers...........................................24
3.1.2ModifiedStroopParadigm........................................................25
3.2 Implicit attitudes.......................................................................................29
3.3Approachbias ..........................................................................................31
4.0Discussion........................................................................................................33
4.1Differential effects in different populations? ..........................................35
4.2Awareness andmotivation.......................................................................37
4.3Summary..................................................................................................37
5.0References........................................................................................................39
Part2:Empirical Paper...........................................................................................47
1.0 Introduction......................................................................................................49
2.0Method.............................................................................................................55
2.1Participants...............................................................................................55
2.2Overviewofexperimental design............................................................57
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2.3Questionnairemeasures...........................................................................58
2.3.1Depressionand anxiety.............................................................58
2.3.2 Impulsivity................................................................................58
2.3.3Substanceuse............................................................................59
2.3.4Subjectivecraving.....................................................................59
2.4Attentional bias tasks...............................................................................59
2.4.1Stimuli.......................................................................................60
2.4.2Assessment ofattentional bias..................................................60
2.4.2.1Baseline assessment ofattentional bias .....................63
2.4.2.2Follow-upassessment ofattentional bias...................63
2.4.3Attentional bias modification....................................................63
2.4.4Contingencyawareness.............................................................64
2.5Procedure..................................................................................................64
2.6DataAnalysis...........................................................................................66
2.6.1Attrition.....................................................................................66
2.6.2Preparationofdata....................................................................66
3.0Results..............................................................................................................67
3.1Participant characteristics.........................................................................67
3.2ABat baseline..........................................................................................69
3.3Effects of ABM on AB............................................................................69
3.3.1 Immediateeffects forall participants........................................69
3.3.2Effects overtimeforthepatient group.....................................70
3.4Effects of ABM on cravingforpatient grouponDay1..........................70
3.5Othermainanalyses.................................................................................71
3.6Secondaryanalysis: theroleoftreatment adherence...............................71
4.0Discussion........................................................................................................74
4.1Possiblereasons for non-significant findings..........................................75
4.2Methodological issues..............................................................................77
4.3Clinical andresearch implications...........................................................79
5.0References........................................................................................................83
Part3:Critical Appraisal........................................................................................90
Ethics ApplicationProcess......................................................................................91
SharedProjects........................................................................................................93
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Issues inRecruitment...............................................................................................93
SampleSizeandStatistical Power.................................................................96
HowConductingtheResearchModifiedMyUnderstandingofABM...................97
TheRelativeSuccess of InterventionAcross Different Disorders................98
Ways Forwardwith InterventionResearch: Public Health Initiatives?.........99
References..............................................................................................................101
Appendices..............................................................................................................102
Appendix A: Searchterms usedforliteraturesearch ...........................................103
Appendix B: Contributionofindividual persons toVolume2,Part 2..................106
Appendix C: ParticipantInformationSheet (patient group)..................................108
Appendix D: Participant InformationSheet (control group(IAPT))....................111
Appendix E: Participant InformationSheet (control group(healthy))..................114
Appendix F: Consent form (patient group)...........................................................117
Appendix G: Consent form (control group(IAPT))..............................................119
Appendix H: Consent form (control group(healthy)) ..........................................121
Appendix I: NHS REC ethical approval letter......................................................123
AppendixJ: UCLPaLS ethical approval letter.....................................................127
Appendix K: Barratt Impulsiveness Scale-11........................................................130
Appendix L: Visual AnalogueScales used ..........................................................132
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Listof Tables
Part1:Literature Review
Table1 Keycharacteristics ofstudies includedinthereview. 18
Table2 Scores obtainedbyeach studyontheDowns & Black 19
(1998)critical appraisal tool.
Table3 Weeklyalcohol consumptionofparticipants inthefour 22
modifieddot-probeABM studies recruitingalcohol
drinkers.
Part2:Empirical Paper
Table1 SummaryofABtask specifications. 60
Table2 Mean(SD)ofdemographicandbaselinevariables for 68
each group.
Table3 Total numberandpercentageoftrials removeddueto 70
incorrect responseorreactiontimes beyondthepre-
specifiedlimits.
Table4 Clinicallyrelevant variables at baselineforopiate 72
dependent participants whowereusingontop,not
usingontop,andcontrol participants.
Table5 Numberofpatient participants usingillicit substances 73
ontopoftheirprescribed substitute,includingmean
quantityusedoverthepast 28-days foreach group.
Table6 Baseline attentional bias scores forpatient participants 74
whouseontop,donot useontop,andcontrol
participants.
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Listof Figures
Part1:Literature Review
Figure1 Avisual representationofthesequenceof events ina 21
singletrial ofthemodifiedvisual probetask.
Part2:Empirical Paper
Figure1 Examples ofopiate-neutral (toptworows)andneutral- 61
neutral (bottom row)picturepairstimuli usedinthe
visual probetasks.
Figure2 Avisual representationofasingletrial ofthe 62
modifiedvisual probetask.
Figure3 Overviewoftheexperimental procedure. 65
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Acknowledgements
IwouldliketothankClareWellingtonforherhelpandsupport throughout
theentireprocess ofcompletingthis thesis. Similarly, IwouldliketothankClaire
Mokrysz forherhelpinrecruitment andtestingof researchparticipants, and DrTom
Freemanforhis expertiseinprogrammingthe computertasks usedintheresearch.
In addition, IwouldliketothankProfValerieCurranandDr Dominic
O’Ryanfortheirtireless provisionofexpertise,supervisionand guidanceoverthe
past few years.
Finally, Iam verygrateful toall oftheparticipants whotookpart inthe
research,as well as tothe staffofservices inwhichtheresearchtookplace.
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Part 1: Literature Review
The modification of implicit processes in substance users: a review