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NationalInstituteonDrugAbuse(NIDA)

BringingthePowerofSciencetoBearonDrugAbuseandAddiction

LastUpdatedJanuary2007

https://www.drugabuse.gov

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TableofContents

BringingthePowerofSciencetoBearonDrugAbuseandAddiction

SectionI

SectionII

SectionIII

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SectionI

1:NIDAisdedicatedtobringingthepowerofsciencetobearondrugabuseandaddiction

TheNationalInstituteonDrugAbuse(NIDA)ispartoftheNationalInstitutesofHealthandisdedicatedtobringingthepowerofsciencetobearondrugabuseandaddiction.

Whenapersonfirstthinksabouttryingdrugs,itisusuallyavoluntarydecision.“MaybeIshouldseewhatit’slike...justthisonce,”youmightthink.Orafrienddaresyou.Oryoujustwanttofeelgoodorforgetyourtroubles.Mostdrugsofabuse-includingnicotine,alcohol,marijuana,cocaine,andheroin-activateapartofthebraincalledtherewardsystem,andthatmakesyoufeelgood.But

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justforalittlewhile.

Drugabusehasseriousconsequences.Themostseriousconsequenceisthatprolongeddrugusecanchangethebraininfundamentalandlong-lastingways.Eventually,itbecomesdifficulttodeerivepleasurefromothernormalactivities,suchassports,food,orsex.

Afterrepeateddruguse,youreachapointwhendecidingtousedrugsisnolongervoluntary.Scientistshaveproofnowthatdrugsliterallychangeyourbrain.It’sasifa“switch”goesoffinthebrain.Itisduringthistransformationprocessthatadrugabuserbecomesadrugaddict.

Addictionisachronicrelapsingdiseasecharacterizedbycompulsive,oftenuncontrollable,drugseekinganddruguseinthefaceofnegativeconsequences.Drugaddictsneedprofessionalhelpandtreatmenttohelpthemcopewiththesechangesandpossiblychangethebrainbacktonormal.

2:Thebrainisthemostcomplexorganinthebody

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Thebrainismadeupofacomplexnetworkofbillionsofnervecellscalledneurons,aswellasotherkindsofcells,allprotectedbythebonesoftheskull.Thetypicalbrainweighsonlyabout3pounds,butitisthesourceofmostqualitiesthatmakeyouwhoyouare.Neuronsinthebrainandspinalcordarepartofthenervoussystemandactasabody’s“CommandCentral.”

Thebrainisconstantlyactive,evenwhenweareasleep.Asamatteroffact,asleeporawake,thebrainrequires20percentoftheheart’soutputoffreshbloodand20percentoftheblood’soxygenandglucosetokeepfunctioningproperly.Glucoseisatypeofsugarthatisourbrain’sprimaryfuel.

Thebrainproducesenoughelectricalenergytopowera40-wattlightbulbfor24hours.That’salotofenergyforahumanorganalittlebiggerthanasoftball.

3:Howaneuronworks

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Neuronsareuniquebecausetheycansendinformationfromthebraintotherestofthebody.Yourbraincommunicateswiththerestofyourbodybysendingmessagesfromoneneurontothenextandultimatelytothemusclesandorgansofthebody.Neuronscanalsostoreinformationasmemories.

Typically,aneuroncontainsthreeimportantparts:acellbodythatdirectsallactivitiesoftheneuron;dendrites(thepartthatlooksliketreebranches),whichareshortfibersthatreceivemessagesfromotherneuronsandrelaythosemessagestothecellbody;andtheaxon,alongsinglefiberthattransmitsmessagesfromthecellbodytodendritesofotherneurons.Everymoment,messagesaremovingwithamazingspeedbackandforthfromneurontoneuron.Asamatteroffact,scientistsoftencomparetheactivityofneuronstothewayelectricityworks.

Aneuroncommunicateswithotherneuronsatspecialplacescalledsynapsesorsynapticclefts.Tosendamessage,aneuronreleasesachemicalmessenger,orneurotransmitter,intothesynapticcleft.Fromthere,the

Illustrationusedwithpermission,courtesyofLydiaV.KibiukandtheSocietyforNeuroscience

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neurotransmittercrossesthesynapseandattachestokeysitescalledreceptorsonthenextneuroninline.Whenneurotransmittersattachtothesereceptors,theycausechangesinsidethereceivingneuronandthemessageisdelivered.

Neuronscommunicatewitheachotherthroughanetworkofinterconnectedcellsthatscientistsarestilltryingtofullyunderstand.Scientistsdoknowthatthiscomplexcommunicationsystemwithinthebraincanbedisruptedbythechemicalsindrugs.Didyouknowthatmorethan400chemicalsareinamarijuanaleaf?Andover4,000chemicalsbesidesnicotineareintobacco!

4:Thebrainisyourbody

Yourbraincontrolsmorethanthewayyouthink.Thebraincontrolsourphysicalsensationsandbodymovements.Howweunderstandwhatwesee,hear,smell,taste,andtouch.Oursenseofbalanceandcoordination.Memory.Feelingsofpleasureandreward.Theabilitytomakejudgments.Whenwecatchafootball,dance,jog,speak,sing,laugh,whistle,smile,cry-that’sourbrainreceiving,processing,andsendingoutmessagestodifferentpartsofour

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body.

Whenwefeelgoodforwhateverreason-laughingwithafriendorseeingagoodmovieoreatingourfavoriteicecream-thebrain’srewardsystemisactivated.Aswesaidbefore,therewardsystemisthepartofthebrainthatmakesyoufeelgood.Therewardsystemisacollectionofneuronsthatreleasedopamine,aneurotransmitter.Whendopamineisreleasedbytheseneurons,apersonfeelspleasure.

Scientistshavelinkeddopaminetomostdrugsofabuse-includingcocaine,marijuana,heroin,alcohol,andnicotine.Thesedrugsallactivatetherewardsystemandcauseneuronstoreleaselargeamountsofdopamine.Overtime,drugsdamagethispartofthebrain.Asaresultofthisdamage,thingsthatusedtomakeyoufeelgood-likeeatingicecream,skateboarding,orgettingahug-nolongerfeelasgood.

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SectionII

1:Controlcentersinthebrainareaffectedbydruguse

Drugsofabusedisableordisruptimportantbrainfunctions.

Whensomeonesmokesmarijuana,forexample,thechemicalTHC(delta-9-tetrahydrocannabinol),themainpsychoactiveingredientinmarijuana,travelsquicklytothebrain.Wecanseetheareasofthebrain(indarkpink)whereTHCconcentrates.Let’sgobacktothepreviousimageandseetheareasofthebrainthatareaffectedbyTHC.

[PRESENTER:Pleasereturntothepreviousimageandpointouttheseareas.]

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YoucanseethatTHCbuildsupinareasthatcontrolthebody’smovements,balance,coordination,memoryandjudgmentabilities,andsensations.THCdisruptsyourbrain’sabilitytocontroltheseactivitiesaswellasyoucouldnormally.

2:Apositronemissiontomography(PET)scanner

Nowlet’stakealookinsideyourmind...OneofthetoolsthatscientistsusetoseetheeffectsofdrugsonthebrainiscalledpositronemissiontomographyoraPET[saytheword“pet”]scan.Similartoanx-ray,butmuchmoresophisticated,aPETscanisusedtoexaminemanydifferentorgansincludingtheheart,liver,lungs,andbones,aswellasthebrain.APETscanshowsmuchmorethanthephysicalstructureofboneandtissue.APETscanshowshowwell(orhowlittle)anorganisfunctioning.

UsingaPETscan,adoctororascientistcanseewhatisactuallyhappeningin

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aperson’sbrainandseetheeffectsofdrugs.ThePETscanshowsareasofthebrainthatareactiveandalsoareasthatareinactiveornotfunctioningatall.Typically,aPETscantakes1to2hourswiththepersonlyingcompletelystillsothatthePETimageswillbeclear.

Let’sseetheeffectsadruglikecocainehasonthebrain.

3:Thisisliterallythebrainondrugs

Whensomeonegets"high"oncocaine,wheredoesthecocainegointhebrain?Withthehelpofaradioactivetracer,thisPETscanshowsusaperson'sbrainoncocaineandtheareaofthebrain,highlightedinyellow,wherecocaineis"binding"orattachingitself.ThisPETscanshowsusminutebyminute,inatime-lapsedsequence,justhowquicklycocainebeginsaffectingaparticular

PhotocourtesyofNoraVolkow,Ph.D.Mappingcocainebindingsitesinhumanandbaboonbraininvivo.FowlerJS,VolkowND,WolfAP,DeweySL,SchlyerDJ,Macgregor,HitzemannR,LoganJ,BendreimB,GatleyST,etal.Synapse1989;4(4):371-377.

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areaofthebrain

Westartintheupperlefthandcorner.Youcanseethat1minuteaftercocaineisadministeredtothissubjectnothingmuchhappens.Allareasofthebrainarefunctioningnormally.Butafter3to4minutes[thenextscantotheright],weseesomeareasstartingtoturnyellow.Theseareasarepartofabrainstructurecalledthestriatum[stry-a-tum]thatisthemaintargetinthebrainboundandactivatedbycocaine.

Atthe5-to8-minuteinterval,weseethatcocaineisaffectingalargeareaofthebrain.Afterthat,thedrug'seffectsbegintowearoff.Atthe9-to10-minutepoint,thehighfeelingisalmostgone.Unlesstheabusertakesmorecocaine,theexperienceisoverinabout20to30minutes.

Scientistsaredoingresearchtofindoutifthestriatumproducesthe"highfeeling"andcontrolsourfeelingsofpleasureandmotivation.Oneofthereasonsscientistsarecuriousaboutspecificareasofthebrainaffectedbydrugssuchascocaineistodeveloptreatmentsforpeoplewhobecomeaddictedtothesedrugs.Scientistshopetofindthemosteffectivewaytochangeanaddictedbrainbacktonormalfunctioning.

4:Long-termeffectsofdrugabuse

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ThisPETscanshowsusthatonceaddictedtoadruglikecocaine,thebrainisaffectedforalong,longtime.Inotherwords,onceaddicted,thebrainisliterallychanged.Let’sseehow...

Inthisimage,thelevelofbrainfunctionisindicatedinyellow.Thetoprowshowsanormal-functioningbrainwithoutdrugs.Youcanseealotofbrainactivity.Inotherwords,thereisalotofyellowcolor.

Themiddlerowshowsacocaineaddict’sbrainafter10dayswithoutanycocaineuseatall.Whatishappeninghere?[Pauseforresponse.]Lessyellowmeanslessnormalactivityoccurringinthebrain-evenafterthecocaineabuserhasabstainedfromthedrugfor10days.

PhotocourtesyofNoraVolkow,Ph.D.VolkowND,HitzemannR,WangG-J,FowlerJS,WolfAP,DeweySL.Long-termfrontalbrainmetabolicchangesincocaineabusers.Synapse11:184-190,1992;VolkowND,FowlerJS,WangG-J,HitzemannR,LoganJ,SchlyerD,DeweyS,WolfAP.DecreaseddopamineD2receptoravailabilityisassociatedwithreducedfrontalmetabolismincocaineabusers.Synapse14:169-177,1993.

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Thethirdrowshowsthesameaddict’sbrainafter100dayswithoutanycocaine.Wecanseealittlemoreyellow,sothereissomeimprovement-morebrainactivity-atthispoint.Buttheaddict’sbrainisstillnotbacktoanormalleveloffunctioning...morethan3monthslater.Scientistsareconcernedthattheremaybeareasinthebrainthatneverfullyrecoverfromdrugabuseandaddiction.

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SectionIII

1:Drugshavelong-termconsequences

Hereisanotherexampleofwhatsciencehasshownusaboutthelong-termeffectsofdrugs.WhatthisPETscanshowsusishowjust10daysofdrugusecanproduceverydramaticandlong-termchangesinthebrainofamonkey.Thedrugintheseimagesisamphetamine,orwhatsomepeoplecall“speed.”Rememberthepreviousimageshoweduswhatthebrainofachroniccocaineabuserlookslike.Thisimageshowsuswhatusingadruglikeamphetaminecandoinonly10daystothebrainofamonkey.

Thisimagealsogivesusabetterideaofwhatmethamphetamine,adrugsimilar

PhotocourtesyofNIDAfromresearchconductedbyMelegaWP,RaleighMJ,StoutDB,LacanC,HuangSC,PhelpsME.Recoveryofstriataldopaminefunctionafteracuteamphetamine-andmethamphetamine-inducedneurotoxicityinthevervetmonkey.BrainRes1997Aug22;766(1-2);113-120.

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instructure,candotothebrain.Methamphetamineuseisbecomingincreasinglypopularincertainareasofthecountry.

Thetoprowshowsus,inwhiteandred,normalbrainactivity.Thesecondrowshowsusthatsamebrain4weeksafterbeinggivenamphetaminefor10days.Thereisadramaticdecreaseinbrainactivity.Thisdecreasedbrainactivitycontinuesforupto1yearafteramphetamineuse.Thesecontinuousbrainchangesoftentriggerotherchangesinsocialandemotionalbehavior,too,includingapossibleincreaseinaggressiveness,feelingsofisolation,anddepression.

2:Thememoryofdrugs

Thisimagedemonstratessomethingreallyamazing-howjustthementionofitemsassociatedwithdrugusemaycauseanaddictto“crave”ordesiredrugs.ThisPETscanispartofascientificstudythatcomparedrecoveringaddicts,whohadstoppedusingcocaine,withpeoplewhohadnohistoryofcocaineuse.The

PhotocourtesyofAnnaRoseChildress,Ph.D.

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studyhopedtodeterminewhatpartsofthebrainareactivatedwhendrugsarecraved.

Forthisstudy,brainscanswereperformedwhilesubjectswatchedtwovideos.Thefirstvideo,anondrugpresentation,showednatureimages-mountains,rivers,animals,flowers,trees.Thesecondvideoshowedcocaineanddrugparaphernalia,suchaspipes,needles,matches,andotheritemsfamiliartoaddicts.

Thisishowthememoryofdrugsworks:Theyellowareaontheupperpartofthesecondimageistheamygdala(a-mig-duh-luh),apartofthebrain’slimbicsystem,whichiscriticalformemoryandresponsibleforevokingemotions.Foranaddict,whenadrugcravingoccurs,theamygdalabecomesactiveandacravingforcocaineistriggered.

Soifit’sthemiddleofthenight,raining,snowing,itdoesn’tmatter.Thiscravingdemandsthedrugimmediately.Rationalthoughtsaredismissedbytheuncontrollabledesirefordrugs.Atthispoint,abasicchangehasoccurredinthebrain.Thepersonisnolongerincontrol.Thischangedbrainmakesitalmostimpossiblefordrugaddictstostaydrug-freewithoutprofessionalhelp.Becauseaddictionisabraindisease.

3:Amessagetoremember

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Wediscussedmanyimportantpointstoday.Twopoints,inparticular,Ihopeyouremember.Oneisthatdrugabuseandaddictionaffecteverysegmentofsociety.That’sallofus.Everyone.Notonepersonisimmunefromthediseaseofaddiction.

Theseimagestodaydemonstratethatthereareobservablechangesinbrainfunctionthattakeplacewhendrugsareused.Wesawthatthebrainsofaddictsaredifferentfromthebrainsofpeoplewhoarenotaddicted.Anditisdifficult,insomecasesimpossible,toreturnthebraintonormal.Scientists,likethosewhoworkattheNationalInstituteonDrugAbuse,areworkingtodeveloptreatmentstohelppeoplewhoareaddictedtodrugs.Buttreatment,likeaddiction,isacomplexissue.

4:Isitworththerisk?

CourtesyofPartnershipforaDrugFreeAmerica.

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Whatpercentageofpeoplewhoexperimentwithdrugswillbecomeaddicted?[Pauseforresponses.]Rightnow,sciencedoesn’thavetheanswertothatquestion.Theeffectsofdrugsonthebrainarestillbeingstudiedandexplored.

Andwhenwetalkaboutdrugs,wearenotjusttalkingaboutcocaineandmarijuanaandamphetaminesandinhalants.Nicotineishighlyaddictivetoo,and,formanypeople,soisalcohol.Forgetthestereotypeofadrugaddicthangingoutonadangerousstreetcorner.Anyonecangethookedondrugs-yourfriends,membersofyourfamily,yourneighbors.

Tryingadrugjustbecauseafriendsaysit’s“cool,”mightcostyoumuchmorethanyoubargainedfor.Soeverypersoninthisroomhastodecideforthemselves:Isitworththerisk?

Thegoodnewsis:Helpisavailable.

5:VisitNIDA

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We’vecoveredalotofgroundtoday.Bynoweveryonehereshouldhaveanideaofwhatdrugsdotoourbrain,buttheinformationwesharedtodayisjustabeginning.There’smuchmoretodiscoverabouthowthebrainworks.Takesometimeonyourowntolearnaboutthissubject.TheInternetisanexcellentplacetostart.

Tolearnmore,checkoutNIDA’shomepageontheWorldWideWebandseewhatyoucanfindoutaboutthelatestdiscoveriesaboutthebrainandhowitrespondstodrugs.

Forscientists,thebrainisunexploredterritorylikethesurfaceofMarsforthePathfinderexpedition.Itismyhopethatsomeofyouwillbecomescientistsinterestedinhowthebrainworks,sothatyoumighthelpusunderstandmoreaboutaddictionandhelpussolvethisproblem.

6:Haveyouchangedyourmind?

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Hereisourlastimage.Aswelookatside-by-sidePETscansofapersonwhohasneverusedcocainecomparedwithacocaineaddict,canyoutellwhichbrainismoreactiveandhealthy?Takeaguess.Yes,thebrainontheleftwithanabundanceofredisthehealthy,activebrain.

Withalittlebitofknowledgeaboutwhatdrugaddictionactuallyis,anyone-notjustneuroscientistsandneurobiologists-canseethechangesinbrainactivitycausedbydrugabuseandaddiction.ThePETscanswe’velookedattodayprovethat.

We’veseenthescientificfacts.We’velearnedthataddictionisabraindisease.Andwe’vealsolearnedthatscientistsaremakinggreatstridesindevelopingtreatmentsforaddiction.Therewillbenomagiccharmtomakeaddictiongoaway.Buteducatedandinformedwiththescientificfactsaboutwhatdrugscandotothebrain,weareeachinabetterpositiontodecidewhetherornottotakedrugsinthefirstplace.Giventhefacts,haveyouchangedyourmind?

PhotocourtesyofNIDA.IfYouChangeYourMind.Studentmagazine.NIHPublicationNo.93-3474,1993.

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