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MarijuanaandHealth

Addiction

1in10peoplewhotrymarijuanawillbecomeaddictedtoit,developingadependencethatproduceswithdrawal,cravings.

Ifmarijuanausestartsinadolescence,thechancesofaddictionare1in6.i

Long-termstudiesfromtheUSAandNewZealandhaveshownthatregularcannabissmokersreportmoresymptomsofchronicbronchitisthannon-

smokers.ii

Andtoday'smarijuanaisnotthemarijuanaofthe1960s;potencyhastripledinthepast15years,accordingtoa2009reportfromtheU.S.government.Ithasgrown5timessince1960.

IntheU.S.since1990,morepeoplehavegonetotheemergencyroomafterusingmarijuanaeventhoughtheoverallnumbersofmarijuanausershas

remainedrelativelystable.iii

IntheU.S.,cannabisemergencyrateshavebeenrisingsharplyforcannabis-relatedadmissions.Visitstohospitalemergencydepartmentsbecauseof

cannabisusehaverisenfromanestimated16,251visitsin1991tomorethan374,000in2008. iv

TheBrainandMentalHealth

Marijuanausedirectlyaffectsthebrain,specificallythepartsofthebrain

responsibleformemory,learning,attention,andreactiontime.Theseeffectscanlastupto28daysafterabstinencefromthedrug.v

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Scienceconfirmsthattheadolescentbrain,particularlythepartofthebrainthatregulatestheplanningcomplexcognitivebehavior,personality

expression,decision-makingandsocialbehavior,isnotfullydevelopeduntil

theearlytomid-20s.Developingbrainsareespeciallysusceptibletoallofthenegativeeffectsofmarijuanaandotherdruguse.vi

Marijuanauseissignificantlylinkedwithmentalillness,especially

schizophreniaandpsychosis,butalsodepressionandanxiety.vii

TheHeart

Marijuanausecancauseanincreaseintheriskofaheartattackmorethan

four-foldinthehourafteruse,andprovokeschestpaininpatientswithheartdisease.viii

TheLungs

Researchhasshownmarijuanasmoketocontaincarcinogensandtobeanirritanttothelungs,resultingingreaterprevalenceofbronchitis,cough,and

phlegmproduction.ix

Marijuanasmoke,infact,contains50-70percentmorecarcinogenichydrocarbonsthantobaccosmoke.x

Evidencelinkingmarijuanaandlungcanceraremixed,witha recentstudystatingthatcannabissmokingincreasestheriskofdevelopingalungcancerindependentlyofaneventualassociatedtobaccoexposure.xiOtherstudieshavefailedtofindsuchalink.xii

Marijuanasmokealsoincludesanenzymethatconvertssomehydrocarbons intoacancer-causingform,potentiallyacceleratingthechangesthatproducemalignantcells.xiii

MarkGold,perhapsthemostdistinguishedprofessorinthecountryondrugsandthebrainandbody,said,Itispossible,butnotproven,thatcannabis

smokemaybelesstoxicthancigarettesmoke,butitisnotbetterthancleanair.Clear,unbiased,andconvincingevidenceofsafetyandcomparable

efficacyareneededfortherapeuticclaims.Itissmoke,afterall.ColumbusbroughtTobaccototheNewWorldandittooknearly500yearsforabsoluteproofoftobaccosmokedangerousnesstobeestablished,Goldcontinued.

Tothisday,eachyear,over400,000UnitedStatesdeathsareduetotobaccosmoke.

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Pregnancy

Marijuanasmokingduringpregnancyhasbeenshowntodecreasebirth

weight,mostlikelyduetotheeffectsofcarbonmonoxideonthedevelopingfetus.xiv

IQ,Learning,andJobPerformance

Oneofthemostwelldesignedstudiesonmarijuanaandintelligence,releasedin2012,foundthatpersistent,heavyuseofmarijuanaby

adolescentsreducesIQbyasmuchaseightpoints,whentestedwellintoadulthood.xv

Otherstudieshavefoundthatmarijuanauseislinkedwithdroppingoutofschool,andsubsequentunemployment,socialwelfaredependence,anda

lowerself-reportedqualityoflifethannon-marijuanaabusingpeople.xvi

AccordingtotheU.S.NationalSurveyonDrugUseandHealth,youthwithpooracademicresultsweremorethanfourtimesaslikelytohaveused

marijuanainthepastyearthanyouthwithanaverageofhighergrades.Thisisconsistentwithanexhaustivemeta-analysisexaminingforty-eight

differentstudiesbyMacleodandcolleagues,publishedbyLancet,whofound

thatmarijuanauseisconsistentlyassociatedwithreducedgradesandareducedchanceofgraduatingfromschool.xvii

Inaddition,studieshavelinkedemployeemarijuanausewithincreased

absences,tardiness,accidents,workerscompensationclaims,andjob

turnover.xviii

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iWagner,F.A.&Anthony,J.C.Fromfirstdrugusetodrugdependence;developmentalperiodsofrisk

fordependenceuponcannabis,cocaine,andalcohol.Neuropsychopharmacology26,479-488(2002).

iiTetrault,J.M.,Crothers,K.,Moore,B.A.,Mehra,R.,Concato,J.,&Fiellin,D.A.(2007).Effectsofmarijuanasmokingonpulmonaryfunctionandrespiratorycomplications. ArchivesofInternal

Medicine,167(3):221-228.

iiiSubstanceAbuseandMentalHealthServicesAdministration,CenterforBehavioralHealthStatistics

andQuality.(2011).DrugAbuseWarningNetwork,2008:NationalEstimatesofDrug-Related

EmergencyDepartmentVisits.HHSPublicationNo.SMA11-4618.Rockville,MD.

ivSubstanceAbuseandMentalHealthServicesAdministration,CenterforBehavioralHealthStatistics

andQuality.(2011).DrugAbuseWarningNetwork,2008:NationalEstimatesofDrug-Related

EmergencyDepartmentVisits.HHSPublicationNo.SMA11-4618.Rockville,MD.

vHallW&DegenhardL(2009).Adversehealtheffectsofnon-medicalcannabisuse. Lancet,

374:1383-1391

viGiedd.J.N.(2004).Structuralmagneticresonanceimagingoftheadolescentbrain.Annalsofthe

NewYorkAcademyofSciences ,1021,77-85.

viiMooreTH,ZammitS,Lingford-HughesA,etal.Cannabisuseandriskofpsychoticoraffective

mentalhealthoutcomes:Asystematicreview.Lancet370(9584):319328,2007.AlsoLarge,M.,

SharmaS,ComptonM.,Slade,T.&O.,N.(2011).Cannabisuseandearlieronsetofpsychosis:a

systematicmeta-analysis.ArchivesofGeneralPsychiatry.68.AlsoseeArseneaultL,etal.(2002).

Cannabisuseinadolescenceandriskforadultpsychosis:longitudinalprospectivestudy. British

MedicalJournal.325,1212-1213.

viiiHallW&DegenhardL(2009).Adversehealtheffectsofnon-medicalcannabisuse. Lancet,

374:1383-1391.

ixTetrault,J.M.,etal.Effectsofcannabissmokingonpulmonaryfunctionandrespiratory

complications:asystematicreview.ArchInternMed167,221-228(2007).

xHoffman,D.;Brunnemann,K.D.;Gori,G.B.;andWynder,E.E.L.Onthecarcinogenicityofmarijuana

smoke.In:V.C.Runeckles,ed.,RecentAdvancesinPhytochemistry.NewYork:Plenum,1975.

xiBrambilla,C.,&Colonna,M.(2008).Cannabis:Thenextvillainonthelungcancerbattlefield?

EuropeanRespiratoryJournal,31 :227-228.

xiiBello,D.(2006).Largestudyfindsnolinkbetweenmarijuanaandcancer. ScientificAmerican,

Availableat:http://www.scientificamerican.com/article.cfm?id=large-study-finds-no-link

xiiiTashkin,D.P.(1999).Effectsonmarijuanaonthelunganditsdefensesagainstinfectionand

cancer.SchoolPsychologyInternational,20(1):23-37.

xivHallW&DegenhardL(2009).Adversehealtheffectsofnon-medicalcannabisuse. Lancet,

374:1383-1391.

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xvMeieretal.(2012).Persistentcannabisusersshowneuropsychologicaldeclinefromchildhoodto

midlife.ProceedingsoftheNationalAcademyofSciences.

xviFergusson,D.M.andBoden,J.M.(2008),Cannabisuseandlaterlifeoutcomes.Addiction,103:

969976.

xviiMacleod,J.;Oakes,R.;Copello,A.;Crome,I.;Egger,M.;Hickman,M.;Oppenkowski,T.;Stokes-

Lampard,H.;andDaveySmith,G.Psychologicalandsocialsequelaeofcannabisandotherillicitdrug

usebyyoungpeople:Asystematicreviewoflongitudinal,generalpopulationstudies. Lancet

363(9421):1579-1588,2004.

xviiiNationalInstituteonDrugAbuse(NIDA).(2011).ResearchReportSeries:CannabisAbuse.

AccessedNovember2011at

http://www.drugabuse.gov/ResearchReports/Cannabis/cannabis4.html