Theory of Addiction AddictionPressaimstocommunicatecurrentideasandevidenceinthis expandingfield,notonlytoresearchersandpractisinghealthprofessionals, butalsotopolicymakers,studentsandinterestednon-specialists.These publicationsaredesignedtoaddressthesignificantchallengesthataddiction presentstomodernsociety. OtherbooksintheAddictionPressseries ClinicalHandbookofAdolescentAddiction EditedbyR.Rosner 9780470972342 HarmReductioninSubstanceUseandHigh-RiskBehaviour EditedbyR.Pates&D.Riley 9781405182973 InjectingIllicitDrugs EditedbyR.Pates,A.McBride&K.Arnold 9781405113601 NeuroimaginginAddiction EditedbyB.Adinoff&E.Stein 9780470660140 TreatingDrinkersandDrugUsersintheCommunity T.Waller&D.Rumball 9780632035755 UnderstandingandTreatingAddictions:PsychologicalAssessment andIntervention EditedbyA.Copello 9781405124171 Addiction:EvolutionofaSpecialistField EditedbyG.Edwards 9780632059768 Theory of Addiction Second Edition Robert West and Jamie Brown University College London Thiseditionfirstpublished2013,(cid:2)C 2013byJohnWiley&Sons,Ltd. 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LibraryofCongressCataloging-in-PublicationData West,Robert,1955– Theoryofaddiction/RobertWestandJamieBrown.–Secondedition. pagescm Includesbibliographicalreferencesandindex. ISBN978-0-470-67421-5(pbk.:alk.paper) 1.Substanceabuse. 2.Compulsivebehavior. I.Brown,Jamie,1984– II.Title. RC564.W472014 616.86–dc23 2013013746 AcataloguerecordforthisbookisavailablefromtheBritishLibrary. Wileyalsopublishesitsbooksinavarietyofelectronicformats.Somecontentthatappearsinprintmaynot beavailableinelectronicbooks. Coverimage:www.istockphoto.com/stock_shoppe Coverdesignbywww.hisandhersdesign.co.uk Setin10/12.5ptSabonbyAptara(cid:2)R Inc.,NewDelhi,India 1 2013 CONTENTS Preface ix 1 Introduction:journeytothecentreofaddiction 1 Preparingforthejourney 1 Intheend 3 Whatthisbookdoes 5 Thesynthetictheoryofaddictioninbrief 7 References 9 2 Definition,theoryandobservation 10 Definingaddiction(addictionisnotanelephant) 10 Diagnosingandmeasuringaddiction 20 Theoryandsupposition 22 ‘Bigobservations’inthefieldofaddiction 30 Recapitulation 36 References 36 3 Beginningthejourney:addictionaschoice 41 Addictionasareflectivechoice 41 Box3.1 Themythofaddiction 44 Box3.2 Vaguelyrightorpreciselywrong?TheTheoryof RationalAddiction 45 Box3.3 TheSelf-medicationModelofaddiction 50 Box3.4 OpponentProcessTheory 53 Irrational,ill-informedchoiceandunstablepreferences 60 Box3.5 ExpectancyTheories 62 Box3.6 Skog’sChoiceTheory 65 Box3.7 Slovic’sAffectHeuristic 67 Box3.8 CognitiveBiasTheories 70 Box3.9 BehaviouralEconomicTheories 72 Box3.10 GatewayTheory 78 Box3.11 TheTranstheoreticalModelofbehaviourchange 80 Box3.12 Identityshiftsandbehaviourchange 86 Addictionastheexerciseofchoicebasedondesires 87 References 89 v vi ■ Contents 4 Choiceisnotenough:theconceptsofimpulseandself-control 95 Reportsoffeelingsofcompulsion 95 Powerfulmotivesversusimpairedcontrol 96 Box4.1 TheDiseaseModelofaddiction 96 Personalityandaddictiontypologies 98 Box4.2 TridimensionalPersonalityTheory 98 Self-efficacy 100 Box4.3 Self-efficacyTheory 100 Thetransitionfromlapsetorelapse 102 Box4.4 TheAbstinenceViolationEffect 102 Impulsecontrol 105 Box4.5 InhibitionDysregulationTheory 106 Self-regulationasabroadlybasedconcept 108 Box4.6 Self-regulationTheory 108 Urgesandcraving 108 Box4.7 ACognitiveModelofDrugUrges 109 Addictionasafailureofself-controloverdesiresandurges 110 References 111 5 Addiction,habitandinstrumentallearning 114 Instrumentallearning 114 Box5.1 Instrumentallearning(operantconditioning)andaddiction 115 Mechanismsunderpinninginstrumentallearning 118 Box5.2 TheDopamineTheoryofDrugReward 119 Box5.3 Addictionarisingfromfunctionalneurotoxicityofdrugs 121 Classicalconditioning 122 Box5.4 Classicalconditioningandaddiction 122 Morecomplexlearningmodels 124 Box5.5 Addictionasalearning/memoryprocess 125 Box5.6 IncentiveSensitisationTheory 126 Box5.7 Balfour’stheoryofdifferentialdrugeffectswithinthe nucleusaccumbens 129 Sociallearning 130 Box5.8 SocialLearningTheory 131 Associativelearning 133 References 133 6 Addictioninpopulations,andcomprehensivetheories 136 Addictioninpopulations 136 Box6.1 DiffusionTheory 137 Comprehensivetheoriesofaddiction 139 Box6.2 ExcessiveAppetitesTheory 140 Box6.3 ThePathwaysModelofpathologicalgambling 146 Whatisaddictionandhowcanweexplainit? 149 References 150 Contents ■ vii 7 Developmentofacomprehensivetheory 152 Afunctionalclassificationoftheoriesofaddiction 153 Addictionasreflectivechoice 158 Addictionasirrationalchoice 162 Addiction,compulsionandself-control 165 Addiction,instrumentallearningandhabit 168 Addiction,choice,compulsionandhabit 179 References 185 8 Asynthetictheoryofmotivation 192 Understandingbehaviourincontext:theCOM-Bmodel 192 Focusonmotivationaltheory 194 Thehumanmotivationalsystem 194 Structureandfunctionofthehumanmotivationalsystem 195 The‘headmodel’ 205 Momentumandinertia 206 Adaptation:waysinwhichexperienceaffectsmotivationaldisposition 207 The‘representationalsystem’,consciousnessanddualprocessmodels 210 Selfandself-control 213 Mentaleffortandmotivationalresources 216 Whatmotivatesus 216 Theunstablemind 218 Asummary:keypropositionsfromPRIMEtheory 225 References 227 9 Atheoryofaddiction 229 Addictionis 229 Thepathologiesunderlyingaddiction 230 Areturntosome‘bigobservations’aboutaddiction 233 Theabnormalitiesunderlyingaddiction 241 Effectsofinterventions 244 Recommendationsandpredictionsregardingaddictioninterventions 244 Testingthetheory 250 Firstresults 251 Conclusions 252 References 253 Index 257 wwwwwww PREFACE The first edition of Theory of Addiction summarised the major theoretical approaches that attempt to explain the range of phenomena that we call ‘addic- tion’andsynthesisetheseintoanoverarchingtheorythatcapturedtheirmaincore features. It was borne out of a need for a single model that could account for featuresofaddictionthatinvolveconsciouschoice,powerfuldesiresandimpulses, andattemptsat,andfailureof,self-control.Itneededtobringinideasofpleasure- seekingaswellasrelieffrommentalandphysicaldiscomfort.Itneededtoaccount for individual differences in susceptibility to addiction and explain when and why many addicts ‘recover’ without help but also why some interventions help someaddicts.Itneededtoexplainwhypopulation-levelinterventionssuchasprice increases and reductions in availability can influence the prevalence of addiction and why some medicines can help addicts recover without appearing to provide anyofthefunctionsprovidedbytheaddictivebehaviour. Given that motivation lay at the heart of addiction it became apparent that a theoryofaddictionneededtobebuiltonatheoryofmotivation,andthatinvolved creatingasyntheticmodelofmotivation.Afirstdraftofatheorywasconstructed, aimingtobeasparsimoniousaspossible,whilestillaccountingforthefullrangeof ‘bigobservations’.Thegoalwasnotonlytoexplain,butalsotogeneratehypotheses abouthowonemightintervenemoreeffectivelytocombataddiction.Itwasalways intended that the theory would continue to develop, both in order to account for more observations and to make it more useful when it comes to designing interventions. Since the first edition was published, new findings have accumulated and expe- rience has been gathered in communicating the theory. After 6 years, it seemed appropriatetoupdatethebooktotakeaccountofthis.Importantrevisionsinclude thefollowing: 1. Updatingthedefinitionandconceptualisationofaddiction. 2. Updatingdescriptionsoftheoriesintheliterature. 3. Providingafunctionalclassificationoftheoriesandmodelsofaddiction. 4. Providingadescriptionofcoreconceptsinvolvedinthesetheories. 5. Updatingthedescriptionofthesynthetictheoryofaddiction(PRIMETheory) toimproveclarityandtakeaccountofnewobservations. ix