Author's Accepted Manuscript
Predictors of the risk factors for suicide identified by the interpersonal-psychological theory of suicidal behaviour Helen Christensen, Philip James Batterham, Andrew J. Mackinnon, Tara Donker, Andrea Soubelet
www.elsevier.com/locate/psychres
PII: DOI: Reference:
S0165-1781(14)00400-4 http://dx.doi.org/10.1016/j.psychres.2014.05.029 PSY8299
To appear in:
Psychiatry Research
Received date: 31 January 2014 Revised date: 28 April 2014 Accepted date: 17 May 2014 Cite this article as: Helen Christensen, Philip James Batterham, Andrew J. Mackinnon, Tara Donker, Andrea Soubelet, Predictors of the risk factors for suicide identified by the interpersonal-psychological theory of suicidal behaviour, Psychiatry Research, http://dx.doi.org/10.1016/j.psychres.2014.05.029 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
Predictors of IPT Constructs Helen Christensen
Predictors of the risk factors for suicide identified by the Interpersonal-Psychological Theory of Suicidal Behaviour Helen Christensen* a, Philip James Batterham b, Andrew J Mackinnon c, Tara Donker a,d,e, Andrea Soubelet f a
Black Dog Institute, The University of New South Wales, Sydney, Australia
b
Centre for Mental Health Research, The Australian National University, Canberra, Australia
c
Orygen Youth Health, University of Melbourne, Melbourne, Australia
d
Department of Clinical Psychology, VU University, Amsterdam, The Netherlands
e
EMGO Institute for Health and Care Research, VU University, Amsterdam and VU
University Medical Center, The Netherlands f
Faculty of Arts and Humanities, University of Nice - Sophia Antipolis, Nice, France
*Corresponding author: Helen Christensen Black Dog Institute Hospital Road Randwick Sydney NSW 2031 AUSTRALIA AU Tel.: (+61 02) 9382 4530 Fax: (+61 02) 9382 8208 Email: [email protected] Word count: 4,962 Running head: Predictors of IPTS Constructs
2
Predictors of IPT Constructs Helen Christensen PredictorsoftheriskfactorsforsuicideidentifiedbytheInterpersonalPsychologicalTheoryof SuicidalBehaviour HelenChristensen*a,PhilipJamesBatterhamb,AndrewJMackinnonc,TaraDonkera,d,e,Andrea Soubeletf a
BlackDogInstitute,TheUniversityofNewSouthWales,Sydney,Australia
b
c
CentreforMentalHealthResearch,TheAustralianNationalUniversity,Canberra,Australia
OrygenYouthHealth,UniversityofMelbourne,Melbourne,Australia
d
e
DepartmentofClinicalPsychology,VUUniversity,Amsterdam,TheNetherlands
EMGOInstituteforHealthandCareResearch,VUUniversity,AmsterdamandVUUniversity
MedicalCenter,TheNetherlands f
FacultyofArtsandHumanities,UniversityofNiceSophiaAntipolis,Nice,France
*Correspondingauthor:
HelenChristensen
BlackDogInstitute HospitalRoad
Randwick
SydneyNSW2031 AUSTRALIAAU
Tel.:(+6102)93824530
3
Predictors of IPT Constructs Helen Christensen Fax:(+6102)93828208 Email:[email protected]
Wordcount:4,962
Runninghead:PredictorsofIPTSConstructs
Abstract
TheInterpersonalPsychologicalTheoryofSuicide(IPTS)hasbeensupportedbyrecentresearch. However,thenatureofthemodels’threemajorconstructsperceivedburdensomeness,thwarted belongingnessandacquiredcapabilityrequiresfurtherinvestigation.Inthispaper,wetesta numberofhypothesesaboutthepredictorsandcorrelatesoftheIPTSconstructs.Participantsaged 3238fromanAustralianpopulationbasedlongitudinalcohortstudy(n=1,167)wereassessed.IPTS constructsweremeasuredbyitemsfromtheInterpersonalNeedsQuestionnaire(INQ)andAcquired CapabilityforSuicideScale(ACSS),alongsidedemographicandadditionalmeasures,measured concurrentlyorapproximatelyeightyearsearlier.CrosssectionalanalysesevaluatingtheIPTS supportedearlierwork.MentalhealthwassignificantlyrelatedtoallthreeIPTSconstructs,but depressionandanxietycasenesswereassociatedonlywithperceivedburdensomeness.Various socialsupportmeasuresweredifferentiallyassociatedwiththethreeconstructs.Stressfulevents andlifetimetraumashadrobustindependentassociationswithacquiredcapabilityforsuicideonly. TheIPTSmodelprovidesausefulframeworkforconceptualisingsuiciderisk.Thefindingshighlight theimportanceofperceivedsocialsupportinsuiciderisk,identifytheimportanceofpersonalityand otherfactorsasnewavenuesofresearch,andprovidesomevalidationfortheindependenceofthe constructs.
4
Predictors of IPT Constructs Helen Christensen Keywords:Anxiety/anxietydisorders;depression;suicide/selfharm;nonsuicidalselfinjury; epidemiology.
1.Introduction
InhisInterpersonalPsychologicalTheoryofSuicidalBehaviour(IPTS),JoinerT.E.Joiner(2009) proposesthattheinteractionoftwointerpersonalconstructs—thwartedbelongingnessand perceivedburdensomeness—predictsuicidalideation.Thetheorystates,however,thatthis combinationleadstosuicidalbehaviouronlyinthepresenceofanacquiredabilitytoenactself harm.Thwartedbelongingnessariseswhenthe“needtobelong”(toothers)isunmet(VanOrdenet al.,2010).Perceivedburdensomenessreferstothemisperceptionthatoneissoinadequatethat one`sexistenceisaburdenonfriends,familymembersand/orsociety(RibeiroandJoiner(2009). Theacquiredcapabilityforlethalselfinjuryishypothesizedtodevelopthroughexposureandthus habituationtopainfuland/orfearsomeexperiences,andispositedbythetheorytobenecessaryto overcomepowerfulinternalselfpreservationpressures(T.E.Joineretal.,2009)(seeFigure1).The predictionsoftheInterpersonalPsychologicalTheoryhavebeentestedinanadultsample(T.E. Joineretal.,2009),andbyseveralotherpopulationbasedandclinicalresearchstudies(VanOrden, Witte,James,etal.,2008;Cukrowicz,Cheavens,VanOrden,Ragain,&Cook,2011;You,VanOrden, &Conner,2011).
Recently,wetestedtheIPTSmodelinalargecommunitybasedcohortusingproxy measuresandfoundthattheInterpersonalPsychologicalTheorymodelaccountedformore varianceinsuicidalbehaviourthandidepidemiologicalmodelsincorporatinganxietyanddepression aspredictors(Christensen,Batterham,Soubelet,&Mackinnon,2013).Suicideplans/attemptswere predictedbythecombinationofsuicideideationandselfharm,thelatteractingasaproxymeasure ofacquiredcapability,consistentwiththeIPTStheory.However,theinteractionbetweenperceived burdensomenessandthwartedbelongingnessdidnotsignificantlypredictideation,contrarytothe IPTS.Areplicationofthesefindingsisclearlywarrantedusingtheoriginal(asopposedtotheproxy)
5
Predictors of IPT Constructs Helen Christensen scalestomeasureperceivedburdensomenessandthwartedbelongingness[InterpersonalNeeds Questionnaire(INQ)]andacquiredcapability[AcquiredCapabilityforSuicideScale(ACSS)].
Moreimportantly,giventhattheIPTSmodelwasfoundtobesuperiortotraditional epidemiologicalmodelsinpredictingbehaviour,aninvestigationofthefactorswhichareassociated withthethreeIPTSconstructsmayimproveourunderstandingofpathwaystosuicide.Riskfactors forsuicidalbehaviourhavebeenextensivelyreviewed[see(VanOrdenetal.,2010)]andinclude, amongstothers,previoussuicideattempts(Christiansen&Jensen,2007),familyhistory(Runeson& Asberg,2003),mentaldisorders(Nocketal.,2009),familyconflict(T.E.Joineretal.,2009),physical illness(Huntetal.,2009),socialisolation(Wyder,Ward,&DeLeo,2009),andunemployment(Bastia &Kar,2009).However,advancesinsuicideriskpredictionmaywellbeservedbyinvestigatingin moredetailassociatesofIPTSconstructs,giventhecogencyofJoiner’smodel.
FollowingfromJoiner’swritings,wehypothesizethatperceivedburdensomenesswillbe associatedwithstrongerfamilyorfriendshiprelationships.Inourview,burdensomenessarises fromattachmenttoothers.Thatis,onemaybemorelikelytofeelasthoughtheyareputting someoneelseoutifthereisagreateremotionalconnectionandinvestmentintherelationship.The oppositehasbeenarguedbyotherresearchersthatweakornegativefamilyrelationships,suchas viachildhoodmaltreatment,willpredisposeindividualstoperceivetheyareunwantedor expendable(VanOrdenetal.,2010),whichthenincreasespercievedburdensomeness.However, thereisscantliteraturetosupportthesecontradictoryviews,andfurtherresearchisrequired.
Wehypothesisethatthwartedbelongingnessarisesfrompoorsocialrelationships,the
causesofwhichmaybeeitherthatthepersonhascharacteristicsthatcausehimorhertobe rejected(suchaspsychoticism),orcharacteristicsthatstopthepersonfrominteracting appropriatelywithothers(suchassocialanxietyandwithdrawal).Thwartedbelongingnessmayalso berelatedtoahistoryofabuse,whichitselfwouldleadtopoorbonding.Theevidenceforthese hypothesisedrelationshipsisweak,andfurtherresearchisrequired,althoughevidenceexiststhat
6
Predictors of IPT Constructs Helen Christensen childhoodmaltreatmentmayincreaselevelsofthwartedbelongingness,possiblythroughan impairedcapacitytorelatetoothers(Twomey,Kaslow,&Croft,2000).
Wehypothesisethatacquiredcapacityforsuicidemightbepredictedbyselfharmand
exposuretotrauma,violenceandabuse.ThesepredictionsarisedirectlyfromJoiner’sworkwhich suggeststhatacquiringthecapacityforsuicidearisesthroughpriorsuicidalbehaviourandexposure tootherpainfulandfearinducingbehaviours(e.g.,nonsuicidalselfinjury,selfstarvation,physical abuse)(T.E.Joineretal.,2009).Theevidenceforthesefactorsaspredictorsofacquiredcapabilityis strongerthanthatfoundforpredictorsoftheothertwoconstructs.Suicideattemptriskishigher amongindividualswhohavealongerhistoryofselfinjury,useagreaternumberofmethods,and reportabsenceofphysicalpainduringselfinjury(Nock,Joiner,Gordon,LloydRichardson,& Prinstein,2006;Gordonetal.,2010).Painfulandprovocativeexperiences(e.g.,childhood maltreatment,impulsivity,previoussuicideattempts)andtheacquiredcapabilityforsuicide correlatewiththenumberofprevioussuicideattempts(VanOrden,Witte,Gordon,Bender,& Joiner,2008;VanOrdenetal.,2010).Individualsengaginginmoreprovocativeexperiences(e.g., shoplifting,promiscuoussex,physicalfights)alsoreportedhigheracquiredcapabilityscores(Van Orden,Witte,Gordon,etal.,2008). Inshort,thepresentstudyhastwoaims.Thefirstistoconfirmearlierfindingsvalidatingthe IPTSusingearlierwavesofacommunitybasedlongitudinalstudy,thistimeusingtheINQandACSS measures,ratherthanthe‘proxy’measuresusedinourfirststudy.Wehypothesisethatasignificant interactionbetweenthwartedbelongingnessandperceivedburdensomenessmaygiveriseto suicideideation.Weexpectasignificantinteractionbetweenideationandacquiredcapabilityin predictingsuicideattempt.Thesecondaimistoidentifypredictorsofthwartedbelongingness, perceivedburdensomenessandacquiredcapabilityforsuicide.Inparticular,weareinterestedin contextualvariablesthatmaybepotentialpredictorsofburdensomenessandthwarted belongingness,includingpositiveandnegativesupportfromfriendsandfamily,psychological
7
Predictors of IPT Constructs Helen Christensen characteristicsthatmightinteractwithrelationshipssuchasruminativestyle,mastery,personality traits(neuroticism,extraversion,psychoticism)andlifetimetraumas,includinghistoryofabuse.We alsoincludemeasuresthatwehypothesisemaybeassociatedwithacquiredcapability–suchas stressfullifeevents,lifetimetraumas,andhistoryofsuicidalthoughtsorattempts.Wealso investigatewhetherthosewithacquiredcapabilitypossesshigherlevelsofmastery.Themodelwe usedalsoincludesdemographicvariablesandphysicalandmentalhealthvariablescomprisingSF12 physicalandmentalhealthscores,presenceofGeneralisedAnxietyDisorder(GAD)andMajor DepressiveDisorder.
2.Method
2.1.Participantsandprocedure ThePATHThroughLifeProjectisapopulationbasedstudyexaminingthehealthandwell beingofpeoplewhowereinitially2024,4044,and6064yearsofage(Ansteyetal.,2012).Each cohortisbeingfollowedupeveryfouryearsoveratotalperiodof20years.Participantswere randomlysampledfromtheelectoralrollsofCanberraandQueanbeyan,Australia.Registrationon theelectoralrolliscompulsoryforAustraliancitizens.Resultspresentedhereconcernonlythe20’s cohort,withdatafromthefourthwaveofinterviewsconductedin20112012,whenparticipants wereaged3238(themajoritybeing3337).Atthefirstwave,interviewswerecompletedwith2,404 inthe2024yearagegroup.Theparticipationrateofthosewhowerefoundtobeintheappropriate agerangewas58.6%.Followupinterviewswerecompletedby1,191(49.5%)participantsatWave4, 16yearsaftertheinitialinterview,withafurther95partialcompletions(53.5%total).Theresponse ratewasmarkedlylowerthanforpreviousinterviewwaves(88.6%and79.7%atWaves2and3), duetoreducedprojectfundingthatrequiredtheinterviewsbelargelyconductedonline.After exclusiononthebasisofmissingoutcomedata,thesamplesizeforregressionanalyseswas1,167. However,1233provideddataonsuicidalideationand1223provideddataonsuicide plans/behaviours,alongwithcompletingtheINQandACSSscales.Therewerenosignificant
8
Predictors of IPT Constructs Helen Christensen differencesintheratesofsuicidalideation(2=1.65,p=0.199),suicidalbehaviours(2=0.02,p= 0.881),presenceofanxiety(2=3.41,p=0.065)orpresenceofdepression(2=1.56,p=0.212)at Wave3betweenthosewhodid/didnotcompleteW4.ThosewhocompletedW3butnotW4had significantlylesseducation(14.0vs14.4y)andfemaleshadsignificantlyhigherratesofcompletion (68%ofFvs58%ofM).
2.2.Measures
Thesuicidalideationoutcomewasbasedonendorsementofoneyes/noitemfromthe PsychiatricSymptomFrequency(PSF)scale(Lindelow,Hardy,&Rodgers,1997):“Inthelastyear haveyoueverthoughtabouttakingyourownlife?”assessedatWave4.Suicidalbehaviourwas basedonendorsementofoneormoreofthefollowingyes/noitemsfromthePSF(Lindelow,etal., 1997):“Inthelastyear,haveyouevermadeplanstotakeyourownlife?”,and“Inthelastyear,have youattemptedtotakeyourownlife?”assessedatWave4.AlthoughthePSFincludestheitem “wishedyouweredead”wedidnotincludeit,aspassiveideationislessclearlyalignedtothe conceptofsuicidaldesirethatisusedintheIPTmodel.AccordingtoVanOrdenetal.(2010),the maineffectsofthwartedbelongingnessandperceivedburdensomenesspredictpassivesuicidal ideation.However,thepresenceofbothispredictiveofactivesuicidaldesire,whichiswhatwe aimedtotestinthecurrentpaper.
TheIPTSconstructsofperceivedburdensomenessandthwartedbelongingnesswere assessedusingsevenandfiveitemsrespectivelyfromtheInterpersonalNeedsQuestionnaire(INQ) (VanOrden,Witte,Gordon,etal.,2008).Theseitemsareratedonasevenpointscale,from1“Not atalltrueforme”,through4“Somewhattrueforme”,to7“Verytrueforme.”Perceived burdensomenessandthwartedbelongingnesswerescoredasthemeanitemresponse,rangingfrom 17.AcquiredcapabilityforsuicidewasassessedusingfiveitemsoftheAcquiredCapabilityfor
9
Predictors of IPT Constructs Helen Christensen SuicideScale(ACSS)(VanOrden,Witte,Gordon,etal.,2008).Responsesfortheseitemsarerated from0“Notatalllikeme”to4“Verymuchlikeme”,withtheacquiredcapabilityscoreassessedas themeanofitems,rangingfrom04. Theriskfactorsexaminedweregender,age,yearsofeducationcompleted,numberof recentstressfulevents,numberoflifetimetraumas,positiveandnegativesupportfromfriendsand family,ruminativestyle(Butler&NolenHoeksema,1994),mastery(Pearlin,Menaghan,Lieberman, &Mullan,1981),personalitytraits,SF12physicalandmentalhealthscores(Ware,Kosinski,& Keller,1996),presenceofgeneralizedanxiety,presenceofmajordepression,andpresenceof previoussuicidalideationorattempts.Acountofstressfuleventsinthepastsixmonthswas identifiedfromalistof16events:sufferedillness/injury/assault,relativesuffered illness/injury/assault,parent/child/partnerdied,closefamilyfriend/relativedied,brokeoffa relationship,seriousproblemwithfriend/neighbour/relative,careercrisis,thoughtwouldsoonlose job,partnerthoughttheywouldsoonlosejob,partnerhadcareercrisis,marriageseparation, unemployment,beingfired,financialcrisis,legalproblems,orhavingsomethingvaluablelostor stolen.Lifetimetraumaswereassessedasacountofadverseexperiencesfrom10items,including combatexperience,lifethreateningaccident,naturaldisaster,witnessinginjuryordeath,rape, sexualmolestation,physicalattackorassault,beingthreatenedwithaweapon/held captive/kidnapped,beingtorturedoravictimofterrorism,orotherextremelystressful/upsetting event(Rosenman,2002).Socialsupportwasassessedusingsummedmeasuresofbothnegativeand positivesupportfromfamilyandfriends(Schuster,Kessler,&Aseltine,1990).Thepositiveitems were:“Howoftendo[friends/family]makeyoufeelcaredfor?”and“Howoftendotheyexpress interestinhowyouaredoing?”,whilethenegativeitemswere:“Howoftendo[friends/family]make toomanydemandsonyou?”,“Howoftendotheycriticiseyou?”and“Howoftendo[friends/family] createtensionsorargumentswithyou?”Responsesweregivenonafourpointscalerangingfrom “often”to“never”.Threepersonalitytraitsofneuroticism,extroversionandpsychoticismwere
10
Predictors of IPT Constructs Helen Christensen measuredattheinitialinterview,twelveyearsbeforetheoutcomedatawereassessed,usingthe EysenckPersonalityQuestionnaireRevised(Eysenck,Eysenck,&Barrett,1985).Thesetraitstendto bestable(fouryearreliabilitycorrelationsof0.560.74).Presenceofmajordepressiveepisodewas assessedusingthenineitemPatientHealthQuestionnaire(PHQ9)(Spitzer,Kroenke,&Williams, 1999)whilepresenceofgeneralizedanxietydisorderwasassessedusingtheGAD7scale(Spitzer, Kroenke,Williams,&Lowe,2006).Historyofsuicidalthoughtsorattemptswereassessedbasedon responsestothePsychiatricSymptomFrequencyscale(SF12)(Lindelowetal.,1997)atWaves13.
2.3.Analysis
Differencesbetweenparticipantswithandwithoutsuicidalbehaviourwereassessedusing onewayANOVAandchisquarestatistics.Next,twologisticregressionanalyseswereusedtotest thepredictionsoftheIPTSmodelforsuicidalideation,andsuicidalplansorattempts.The independentvariablesforthesemodelsweretheriskfactorshypothesizedbytheIPTStopredict ideation(perceivedburdensomeness,thwartedbelongingnessandtheinteractionofthesetwo constructs,obtainedbymultiplyingthetwovalues)andattempts(acquiredcapabilityforsuicide). Thehypothesizedinteractionbetweenacquiredcapabilityandideationcouldnotbetestedinthe modelforplan/attempts,asallparticipantswhoreportedaplanorattemptalsoexperienced ideation.Ageandgenderwerealsoincludedinthesemodels,andperceivedburdensomenessand thwartedbelongingnesswereaddedtotheplans/attemptsmodeltogaugewhetherthese constructscontributedfurthertothepredictionofthisoutcome.Forthelogisticregressionanalyses testingtheIPTSmodel,continuousvariableswerecentredatthemean.
Finally,threelinearregressionmodelswereusedtoassesstheassociationbetweentherisk factorsandeachofthethreeIPTSconstructs.Allriskfactorsweresimultaneouslyincludedinthe models.Theorderofpresentationofvariablesinthemodelwasdeterminedbytheconventionof
11
Predictors of IPT Constructs Helen Christensen displayingdemographicvariables,thecoreconstructs,lifeevents,socialrelationships,personality, followedbymentalandphysicalhealthsymptoms.Themodelforeachconstructalsoincludedthe othertwoconstructsasindependentvariables.SPSSversion20wasusedforallanalyses.
3.Results
SamplecharacteristicsarepresentedinTable1,classifiedbypresenceorabsenceofsuicidal thoughts,plansorattempts.Thesamplehadmeanageof34.7and58%ofrespondentswere female.Theriskfactorssignificantlyassociatedwithmoresuicidalthoughts/behaviourunivariately weregreaterperceivedburdensomeness,greaterthwartedbelongingness,greateracquired capabilityforsuicide,morestressfuleventsorlifetraumas,lesspositivesupportfromfriendsor family,morenegativesupportfromfriendsorfamily,higherlevelsofrumination,lowerlevelsof mastery,higherneuroticism,higherintroversionandhigherpsychoticism,poorermentalhealth,and presenceofPHQ9depressionorGAD7anxiety.Nodifferenceswereobservedforage,educationor physicalhealthfactors.
Table2showsdataexaminingtheIPTSmodelinthecommunitycohortof3238yearolds usingthemeasuresofINQandACSS.Omnibuschisquaretestsindicatedthattheoverallmodels weresignificantlyassociatedwithideation(2=176.0,p
Predictors of the risk factors for suicide identified by the interpersonal-psychological theory of suicidal behaviour Helen Christensen, Philip James Batterham, Andrew J. Mackinnon, Tara Donker, Andrea Soubelet
www.elsevier.com/locate/psychres
PII: DOI: Reference:
S0165-1781(14)00400-4 http://dx.doi.org/10.1016/j.psychres.2014.05.029 PSY8299
To appear in:
Psychiatry Research
Received date: 31 January 2014 Revised date: 28 April 2014 Accepted date: 17 May 2014 Cite this article as: Helen Christensen, Philip James Batterham, Andrew J. Mackinnon, Tara Donker, Andrea Soubelet, Predictors of the risk factors for suicide identified by the interpersonal-psychological theory of suicidal behaviour, Psychiatry Research, http://dx.doi.org/10.1016/j.psychres.2014.05.029 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
Predictors of IPT Constructs Helen Christensen
Predictors of the risk factors for suicide identified by the Interpersonal-Psychological Theory of Suicidal Behaviour Helen Christensen* a, Philip James Batterham b, Andrew J Mackinnon c, Tara Donker a,d,e, Andrea Soubelet f a
Black Dog Institute, The University of New South Wales, Sydney, Australia
b
Centre for Mental Health Research, The Australian National University, Canberra, Australia
c
Orygen Youth Health, University of Melbourne, Melbourne, Australia
d
Department of Clinical Psychology, VU University, Amsterdam, The Netherlands
e
EMGO Institute for Health and Care Research, VU University, Amsterdam and VU
University Medical Center, The Netherlands f
Faculty of Arts and Humanities, University of Nice - Sophia Antipolis, Nice, France
*Corresponding author: Helen Christensen Black Dog Institute Hospital Road Randwick Sydney NSW 2031 AUSTRALIA AU Tel.: (+61 02) 9382 4530 Fax: (+61 02) 9382 8208 Email: [email protected] Word count: 4,962 Running head: Predictors of IPTS Constructs
2
Predictors of IPT Constructs Helen Christensen PredictorsoftheriskfactorsforsuicideidentifiedbytheInterpersonalPsychologicalTheoryof SuicidalBehaviour HelenChristensen*a,PhilipJamesBatterhamb,AndrewJMackinnonc,TaraDonkera,d,e,Andrea Soubeletf a
BlackDogInstitute,TheUniversityofNewSouthWales,Sydney,Australia
b
c
CentreforMentalHealthResearch,TheAustralianNationalUniversity,Canberra,Australia
OrygenYouthHealth,UniversityofMelbourne,Melbourne,Australia
d
e
DepartmentofClinicalPsychology,VUUniversity,Amsterdam,TheNetherlands
EMGOInstituteforHealthandCareResearch,VUUniversity,AmsterdamandVUUniversity
MedicalCenter,TheNetherlands f
FacultyofArtsandHumanities,UniversityofNiceSophiaAntipolis,Nice,France
*Correspondingauthor:
HelenChristensen
BlackDogInstitute HospitalRoad
Randwick
SydneyNSW2031 AUSTRALIAAU
Tel.:(+6102)93824530
3
Predictors of IPT Constructs Helen Christensen Fax:(+6102)93828208 Email:[email protected]
Wordcount:4,962
Runninghead:PredictorsofIPTSConstructs
Abstract
TheInterpersonalPsychologicalTheoryofSuicide(IPTS)hasbeensupportedbyrecentresearch. However,thenatureofthemodels’threemajorconstructsperceivedburdensomeness,thwarted belongingnessandacquiredcapabilityrequiresfurtherinvestigation.Inthispaper,wetesta numberofhypothesesaboutthepredictorsandcorrelatesoftheIPTSconstructs.Participantsaged 3238fromanAustralianpopulationbasedlongitudinalcohortstudy(n=1,167)wereassessed.IPTS constructsweremeasuredbyitemsfromtheInterpersonalNeedsQuestionnaire(INQ)andAcquired CapabilityforSuicideScale(ACSS),alongsidedemographicandadditionalmeasures,measured concurrentlyorapproximatelyeightyearsearlier.CrosssectionalanalysesevaluatingtheIPTS supportedearlierwork.MentalhealthwassignificantlyrelatedtoallthreeIPTSconstructs,but depressionandanxietycasenesswereassociatedonlywithperceivedburdensomeness.Various socialsupportmeasuresweredifferentiallyassociatedwiththethreeconstructs.Stressfulevents andlifetimetraumashadrobustindependentassociationswithacquiredcapabilityforsuicideonly. TheIPTSmodelprovidesausefulframeworkforconceptualisingsuiciderisk.Thefindingshighlight theimportanceofperceivedsocialsupportinsuiciderisk,identifytheimportanceofpersonalityand otherfactorsasnewavenuesofresearch,andprovidesomevalidationfortheindependenceofthe constructs.
4
Predictors of IPT Constructs Helen Christensen Keywords:Anxiety/anxietydisorders;depression;suicide/selfharm;nonsuicidalselfinjury; epidemiology.
1.Introduction
InhisInterpersonalPsychologicalTheoryofSuicidalBehaviour(IPTS),JoinerT.E.Joiner(2009) proposesthattheinteractionoftwointerpersonalconstructs—thwartedbelongingnessand perceivedburdensomeness—predictsuicidalideation.Thetheorystates,however,thatthis combinationleadstosuicidalbehaviouronlyinthepresenceofanacquiredabilitytoenactself harm.Thwartedbelongingnessariseswhenthe“needtobelong”(toothers)isunmet(VanOrdenet al.,2010).Perceivedburdensomenessreferstothemisperceptionthatoneissoinadequatethat one`sexistenceisaburdenonfriends,familymembersand/orsociety(RibeiroandJoiner(2009). Theacquiredcapabilityforlethalselfinjuryishypothesizedtodevelopthroughexposureandthus habituationtopainfuland/orfearsomeexperiences,andispositedbythetheorytobenecessaryto overcomepowerfulinternalselfpreservationpressures(T.E.Joineretal.,2009)(seeFigure1).The predictionsoftheInterpersonalPsychologicalTheoryhavebeentestedinanadultsample(T.E. Joineretal.,2009),andbyseveralotherpopulationbasedandclinicalresearchstudies(VanOrden, Witte,James,etal.,2008;Cukrowicz,Cheavens,VanOrden,Ragain,&Cook,2011;You,VanOrden, &Conner,2011).
Recently,wetestedtheIPTSmodelinalargecommunitybasedcohortusingproxy measuresandfoundthattheInterpersonalPsychologicalTheorymodelaccountedformore varianceinsuicidalbehaviourthandidepidemiologicalmodelsincorporatinganxietyanddepression aspredictors(Christensen,Batterham,Soubelet,&Mackinnon,2013).Suicideplans/attemptswere predictedbythecombinationofsuicideideationandselfharm,thelatteractingasaproxymeasure ofacquiredcapability,consistentwiththeIPTStheory.However,theinteractionbetweenperceived burdensomenessandthwartedbelongingnessdidnotsignificantlypredictideation,contrarytothe IPTS.Areplicationofthesefindingsisclearlywarrantedusingtheoriginal(asopposedtotheproxy)
5
Predictors of IPT Constructs Helen Christensen scalestomeasureperceivedburdensomenessandthwartedbelongingness[InterpersonalNeeds Questionnaire(INQ)]andacquiredcapability[AcquiredCapabilityforSuicideScale(ACSS)].
Moreimportantly,giventhattheIPTSmodelwasfoundtobesuperiortotraditional epidemiologicalmodelsinpredictingbehaviour,aninvestigationofthefactorswhichareassociated withthethreeIPTSconstructsmayimproveourunderstandingofpathwaystosuicide.Riskfactors forsuicidalbehaviourhavebeenextensivelyreviewed[see(VanOrdenetal.,2010)]andinclude, amongstothers,previoussuicideattempts(Christiansen&Jensen,2007),familyhistory(Runeson& Asberg,2003),mentaldisorders(Nocketal.,2009),familyconflict(T.E.Joineretal.,2009),physical illness(Huntetal.,2009),socialisolation(Wyder,Ward,&DeLeo,2009),andunemployment(Bastia &Kar,2009).However,advancesinsuicideriskpredictionmaywellbeservedbyinvestigatingin moredetailassociatesofIPTSconstructs,giventhecogencyofJoiner’smodel.
FollowingfromJoiner’swritings,wehypothesizethatperceivedburdensomenesswillbe associatedwithstrongerfamilyorfriendshiprelationships.Inourview,burdensomenessarises fromattachmenttoothers.Thatis,onemaybemorelikelytofeelasthoughtheyareputting someoneelseoutifthereisagreateremotionalconnectionandinvestmentintherelationship.The oppositehasbeenarguedbyotherresearchersthatweakornegativefamilyrelationships,suchas viachildhoodmaltreatment,willpredisposeindividualstoperceivetheyareunwantedor expendable(VanOrdenetal.,2010),whichthenincreasespercievedburdensomeness.However, thereisscantliteraturetosupportthesecontradictoryviews,andfurtherresearchisrequired.
Wehypothesisethatthwartedbelongingnessarisesfrompoorsocialrelationships,the
causesofwhichmaybeeitherthatthepersonhascharacteristicsthatcausehimorhertobe rejected(suchaspsychoticism),orcharacteristicsthatstopthepersonfrominteracting appropriatelywithothers(suchassocialanxietyandwithdrawal).Thwartedbelongingnessmayalso berelatedtoahistoryofabuse,whichitselfwouldleadtopoorbonding.Theevidenceforthese hypothesisedrelationshipsisweak,andfurtherresearchisrequired,althoughevidenceexiststhat
6
Predictors of IPT Constructs Helen Christensen childhoodmaltreatmentmayincreaselevelsofthwartedbelongingness,possiblythroughan impairedcapacitytorelatetoothers(Twomey,Kaslow,&Croft,2000).
Wehypothesisethatacquiredcapacityforsuicidemightbepredictedbyselfharmand
exposuretotrauma,violenceandabuse.ThesepredictionsarisedirectlyfromJoiner’sworkwhich suggeststhatacquiringthecapacityforsuicidearisesthroughpriorsuicidalbehaviourandexposure tootherpainfulandfearinducingbehaviours(e.g.,nonsuicidalselfinjury,selfstarvation,physical abuse)(T.E.Joineretal.,2009).Theevidenceforthesefactorsaspredictorsofacquiredcapabilityis strongerthanthatfoundforpredictorsoftheothertwoconstructs.Suicideattemptriskishigher amongindividualswhohavealongerhistoryofselfinjury,useagreaternumberofmethods,and reportabsenceofphysicalpainduringselfinjury(Nock,Joiner,Gordon,LloydRichardson,& Prinstein,2006;Gordonetal.,2010).Painfulandprovocativeexperiences(e.g.,childhood maltreatment,impulsivity,previoussuicideattempts)andtheacquiredcapabilityforsuicide correlatewiththenumberofprevioussuicideattempts(VanOrden,Witte,Gordon,Bender,& Joiner,2008;VanOrdenetal.,2010).Individualsengaginginmoreprovocativeexperiences(e.g., shoplifting,promiscuoussex,physicalfights)alsoreportedhigheracquiredcapabilityscores(Van Orden,Witte,Gordon,etal.,2008). Inshort,thepresentstudyhastwoaims.Thefirstistoconfirmearlierfindingsvalidatingthe IPTSusingearlierwavesofacommunitybasedlongitudinalstudy,thistimeusingtheINQandACSS measures,ratherthanthe‘proxy’measuresusedinourfirststudy.Wehypothesisethatasignificant interactionbetweenthwartedbelongingnessandperceivedburdensomenessmaygiveriseto suicideideation.Weexpectasignificantinteractionbetweenideationandacquiredcapabilityin predictingsuicideattempt.Thesecondaimistoidentifypredictorsofthwartedbelongingness, perceivedburdensomenessandacquiredcapabilityforsuicide.Inparticular,weareinterestedin contextualvariablesthatmaybepotentialpredictorsofburdensomenessandthwarted belongingness,includingpositiveandnegativesupportfromfriendsandfamily,psychological
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Predictors of IPT Constructs Helen Christensen characteristicsthatmightinteractwithrelationshipssuchasruminativestyle,mastery,personality traits(neuroticism,extraversion,psychoticism)andlifetimetraumas,includinghistoryofabuse.We alsoincludemeasuresthatwehypothesisemaybeassociatedwithacquiredcapability–suchas stressfullifeevents,lifetimetraumas,andhistoryofsuicidalthoughtsorattempts.Wealso investigatewhetherthosewithacquiredcapabilitypossesshigherlevelsofmastery.Themodelwe usedalsoincludesdemographicvariablesandphysicalandmentalhealthvariablescomprisingSF12 physicalandmentalhealthscores,presenceofGeneralisedAnxietyDisorder(GAD)andMajor DepressiveDisorder.
2.Method
2.1.Participantsandprocedure ThePATHThroughLifeProjectisapopulationbasedstudyexaminingthehealthandwell beingofpeoplewhowereinitially2024,4044,and6064yearsofage(Ansteyetal.,2012).Each cohortisbeingfollowedupeveryfouryearsoveratotalperiodof20years.Participantswere randomlysampledfromtheelectoralrollsofCanberraandQueanbeyan,Australia.Registrationon theelectoralrolliscompulsoryforAustraliancitizens.Resultspresentedhereconcernonlythe20’s cohort,withdatafromthefourthwaveofinterviewsconductedin20112012,whenparticipants wereaged3238(themajoritybeing3337).Atthefirstwave,interviewswerecompletedwith2,404 inthe2024yearagegroup.Theparticipationrateofthosewhowerefoundtobeintheappropriate agerangewas58.6%.Followupinterviewswerecompletedby1,191(49.5%)participantsatWave4, 16yearsaftertheinitialinterview,withafurther95partialcompletions(53.5%total).Theresponse ratewasmarkedlylowerthanforpreviousinterviewwaves(88.6%and79.7%atWaves2and3), duetoreducedprojectfundingthatrequiredtheinterviewsbelargelyconductedonline.After exclusiononthebasisofmissingoutcomedata,thesamplesizeforregressionanalyseswas1,167. However,1233provideddataonsuicidalideationand1223provideddataonsuicide plans/behaviours,alongwithcompletingtheINQandACSSscales.Therewerenosignificant
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Predictors of IPT Constructs Helen Christensen differencesintheratesofsuicidalideation(2=1.65,p=0.199),suicidalbehaviours(2=0.02,p= 0.881),presenceofanxiety(2=3.41,p=0.065)orpresenceofdepression(2=1.56,p=0.212)at Wave3betweenthosewhodid/didnotcompleteW4.ThosewhocompletedW3butnotW4had significantlylesseducation(14.0vs14.4y)andfemaleshadsignificantlyhigherratesofcompletion (68%ofFvs58%ofM).
2.2.Measures
Thesuicidalideationoutcomewasbasedonendorsementofoneyes/noitemfromthe PsychiatricSymptomFrequency(PSF)scale(Lindelow,Hardy,&Rodgers,1997):“Inthelastyear haveyoueverthoughtabouttakingyourownlife?”assessedatWave4.Suicidalbehaviourwas basedonendorsementofoneormoreofthefollowingyes/noitemsfromthePSF(Lindelow,etal., 1997):“Inthelastyear,haveyouevermadeplanstotakeyourownlife?”,and“Inthelastyear,have youattemptedtotakeyourownlife?”assessedatWave4.AlthoughthePSFincludestheitem “wishedyouweredead”wedidnotincludeit,aspassiveideationislessclearlyalignedtothe conceptofsuicidaldesirethatisusedintheIPTmodel.AccordingtoVanOrdenetal.(2010),the maineffectsofthwartedbelongingnessandperceivedburdensomenesspredictpassivesuicidal ideation.However,thepresenceofbothispredictiveofactivesuicidaldesire,whichiswhatwe aimedtotestinthecurrentpaper.
TheIPTSconstructsofperceivedburdensomenessandthwartedbelongingnesswere assessedusingsevenandfiveitemsrespectivelyfromtheInterpersonalNeedsQuestionnaire(INQ) (VanOrden,Witte,Gordon,etal.,2008).Theseitemsareratedonasevenpointscale,from1“Not atalltrueforme”,through4“Somewhattrueforme”,to7“Verytrueforme.”Perceived burdensomenessandthwartedbelongingnesswerescoredasthemeanitemresponse,rangingfrom 17.AcquiredcapabilityforsuicidewasassessedusingfiveitemsoftheAcquiredCapabilityfor
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Predictors of IPT Constructs Helen Christensen SuicideScale(ACSS)(VanOrden,Witte,Gordon,etal.,2008).Responsesfortheseitemsarerated from0“Notatalllikeme”to4“Verymuchlikeme”,withtheacquiredcapabilityscoreassessedas themeanofitems,rangingfrom04. Theriskfactorsexaminedweregender,age,yearsofeducationcompleted,numberof recentstressfulevents,numberoflifetimetraumas,positiveandnegativesupportfromfriendsand family,ruminativestyle(Butler&NolenHoeksema,1994),mastery(Pearlin,Menaghan,Lieberman, &Mullan,1981),personalitytraits,SF12physicalandmentalhealthscores(Ware,Kosinski,& Keller,1996),presenceofgeneralizedanxiety,presenceofmajordepression,andpresenceof previoussuicidalideationorattempts.Acountofstressfuleventsinthepastsixmonthswas identifiedfromalistof16events:sufferedillness/injury/assault,relativesuffered illness/injury/assault,parent/child/partnerdied,closefamilyfriend/relativedied,brokeoffa relationship,seriousproblemwithfriend/neighbour/relative,careercrisis,thoughtwouldsoonlose job,partnerthoughttheywouldsoonlosejob,partnerhadcareercrisis,marriageseparation, unemployment,beingfired,financialcrisis,legalproblems,orhavingsomethingvaluablelostor stolen.Lifetimetraumaswereassessedasacountofadverseexperiencesfrom10items,including combatexperience,lifethreateningaccident,naturaldisaster,witnessinginjuryordeath,rape, sexualmolestation,physicalattackorassault,beingthreatenedwithaweapon/held captive/kidnapped,beingtorturedoravictimofterrorism,orotherextremelystressful/upsetting event(Rosenman,2002).Socialsupportwasassessedusingsummedmeasuresofbothnegativeand positivesupportfromfamilyandfriends(Schuster,Kessler,&Aseltine,1990).Thepositiveitems were:“Howoftendo[friends/family]makeyoufeelcaredfor?”and“Howoftendotheyexpress interestinhowyouaredoing?”,whilethenegativeitemswere:“Howoftendo[friends/family]make toomanydemandsonyou?”,“Howoftendotheycriticiseyou?”and“Howoftendo[friends/family] createtensionsorargumentswithyou?”Responsesweregivenonafourpointscalerangingfrom “often”to“never”.Threepersonalitytraitsofneuroticism,extroversionandpsychoticismwere
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Predictors of IPT Constructs Helen Christensen measuredattheinitialinterview,twelveyearsbeforetheoutcomedatawereassessed,usingthe EysenckPersonalityQuestionnaireRevised(Eysenck,Eysenck,&Barrett,1985).Thesetraitstendto bestable(fouryearreliabilitycorrelationsof0.560.74).Presenceofmajordepressiveepisodewas assessedusingthenineitemPatientHealthQuestionnaire(PHQ9)(Spitzer,Kroenke,&Williams, 1999)whilepresenceofgeneralizedanxietydisorderwasassessedusingtheGAD7scale(Spitzer, Kroenke,Williams,&Lowe,2006).Historyofsuicidalthoughtsorattemptswereassessedbasedon responsestothePsychiatricSymptomFrequencyscale(SF12)(Lindelowetal.,1997)atWaves13.
2.3.Analysis
Differencesbetweenparticipantswithandwithoutsuicidalbehaviourwereassessedusing onewayANOVAandchisquarestatistics.Next,twologisticregressionanalyseswereusedtotest thepredictionsoftheIPTSmodelforsuicidalideation,andsuicidalplansorattempts.The independentvariablesforthesemodelsweretheriskfactorshypothesizedbytheIPTStopredict ideation(perceivedburdensomeness,thwartedbelongingnessandtheinteractionofthesetwo constructs,obtainedbymultiplyingthetwovalues)andattempts(acquiredcapabilityforsuicide). Thehypothesizedinteractionbetweenacquiredcapabilityandideationcouldnotbetestedinthe modelforplan/attempts,asallparticipantswhoreportedaplanorattemptalsoexperienced ideation.Ageandgenderwerealsoincludedinthesemodels,andperceivedburdensomenessand thwartedbelongingnesswereaddedtotheplans/attemptsmodeltogaugewhetherthese constructscontributedfurthertothepredictionofthisoutcome.Forthelogisticregressionanalyses testingtheIPTSmodel,continuousvariableswerecentredatthemean.
Finally,threelinearregressionmodelswereusedtoassesstheassociationbetweentherisk factorsandeachofthethreeIPTSconstructs.Allriskfactorsweresimultaneouslyincludedinthe models.Theorderofpresentationofvariablesinthemodelwasdeterminedbytheconventionof
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Predictors of IPT Constructs Helen Christensen displayingdemographicvariables,thecoreconstructs,lifeevents,socialrelationships,personality, followedbymentalandphysicalhealthsymptoms.Themodelforeachconstructalsoincludedthe othertwoconstructsasindependentvariables.SPSSversion20wasusedforallanalyses.
3.Results
SamplecharacteristicsarepresentedinTable1,classifiedbypresenceorabsenceofsuicidal thoughts,plansorattempts.Thesamplehadmeanageof34.7and58%ofrespondentswere female.Theriskfactorssignificantlyassociatedwithmoresuicidalthoughts/behaviourunivariately weregreaterperceivedburdensomeness,greaterthwartedbelongingness,greateracquired capabilityforsuicide,morestressfuleventsorlifetraumas,lesspositivesupportfromfriendsor family,morenegativesupportfromfriendsorfamily,higherlevelsofrumination,lowerlevelsof mastery,higherneuroticism,higherintroversionandhigherpsychoticism,poorermentalhealth,and presenceofPHQ9depressionorGAD7anxiety.Nodifferenceswereobservedforage,educationor physicalhealthfactors.
Table2showsdataexaminingtheIPTSmodelinthecommunitycohortof3238yearolds usingthemeasuresofINQandACSS.Omnibuschisquaretestsindicatedthattheoverallmodels weresignificantlyassociatedwithideation(2=176.0,p
