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Methamphetamine: What Methamphetamine: What can Brain Imaging Tell Us?can Brain Imaging Tell Us?
Thomas E. Freese, Ph.DThomas E. Freese, Ph.D
DirectorDirectorPacific Southwest Addiction Technology Transfer Pacific Southwest Addiction Technology Transfer CenterCenter
Asst. Research PsychologistAsst. Research PsychologistSemel Institute for Neuroscience and Human BehaviorSemel Institute for Neuroscience and Human BehaviorDavid Geffen School of MedicineDavid Geffen School of MedicineUniversity of California at Los AngelesUniversity of California at Los Angeles
www.psattc.orgwww.psattc.orgwww.uclaisap.orgwww.uclaisap.orgtefreese@[email protected]
Supported by:Supported by: Supported by:Supported by: National Institute on Drug Abuse (NIDA)National Institute on Drug Abuse (NIDA) Pacific Southwest Technology Transfer Center (SAMHSA)Pacific Southwest Technology Transfer Center (SAMHSA) International Network of Treatment and Rehabilitation Resource Centres International Network of Treatment and Rehabilitation Resource Centres (UNODC)(UNODC)
May 24, 2006 Orlanndo, Florida
MethamphetamineMethamphetamine
Methamphetamine is a powerful Methamphetamine is a powerful central nervous system stimulantcentral nervous system stimulant that strongly activates multiple that strongly activates multiple systems in the brain. systems in the brain. Methamphetamine is closely Methamphetamine is closely related chemically to related chemically to amphetamine, but the central amphetamine, but the central nervous system effects of nervous system effects of methamphetamine are greater. methamphetamine are greater.
Forms of Forms of MethamphetamineMethamphetamineMethamphetamine Powder
Description: Beige/yellowy/off-white powder
Base / Paste MethamphetamineDescription: ‘Oily’, ‘gunky’, ‘gluggy’ gel, moist, waxy
Crystalline Methamphetamine
IDU Description: White/clear crystals/rocks; ‘crushed glass’ / ‘rock salt’
EPHEDRINE
OH
CC
HHH
3CH 3CH
N
METHAMPHETAM INE
H
CC
HHH
3CH 3CH
N
The Methamphetamine The Methamphetamine Epidemic:Epidemic:Admissions/100,000: 1992-Admissions/100,000: 1992-20032003
0
50
100
150
200
250
300
350
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
California
Hawaii
I owa
Oregon
Washington
It keeps going up
Methamphetamine/Amphetamine Treatment Admissions, by Route of
Administration: 1992-2002
Source: 2002 SAMHSA Treatment Episode Data Set (TEDS).
People use drugs for two reasons:
1) To feel good.
2) To feel better
People use drugs for two reasons:
1) To feel good.
2) To feel better
In other words:
A Major Reason People Take a Drug is they Like
What It Does to Their Brains
In other words:
A Major Reason People Take a Drug is they Like
What It Does to Their Brains
00
5050
100100
150150
200200
00 6060 120120 180180
Time (min)Time (min)
% o
f B
asal
DA
Ou
tpu
t%
of
Bas
al D
A O
utp
ut
NAc shellNAc shell
EmptyEmpty
BoxBox FeedingFeeding
Source: Di Chiara et al.Source: Di Chiara et al.
FOODFOOD
100100
150150
200200
DA
Co
nce
ntr
ati
on
(%
Bas
elin
e)D
A C
on
cen
tra
tio
n (
% B
asel
ine)
MountsMountsIntromissionsIntromissionsEjaculationsEjaculations
1515
00
55
1010
Co
pu
latio
n F
req
ue
nc
yC
op
ula
tion
Fre
qu
en
cy
SampleNumberSampleNumber
11 22 33 44 55 66 77 88 99 1010 1111 1212 1313 1414 1515 1616 1717
ScrScrScrScrBasBasFemale 1 PresentFemale 1 Present
ScrScrFemale 2 PresentFemale 2 Present
ScrScr
Source: Fiorino and PhillipsSource: Fiorino and Phillips
SEXSEX
Natural Rewards Elevate Natural Rewards Elevate Dopamine LevelsDopamine Levels
Natural Rewards Elevate Natural Rewards Elevate Dopamine LevelsDopamine Levels
Source: Shoblock and Sullivan; Di Chiara and Imperato
Effects of Drugs on Dopamine Effects of Drugs on Dopamine ReleaseRelease
00
100100
200200
300300
400400
Time After CocaineTime After Cocaine
% o
f B
as
al
Re
lea
se
% o
f B
as
al
Re
lea
se
DADADOPACDOPACHVAHVA
AccumbensAccumbens COCAINECOCAINE
100
150
200
250
0 1 2 3 4hrTime After Ethanol
% o
f B
as
al
Re
lea
se
0.250.512.5
Accumbens
0
Dose (g/kg ip)
ETHANOL
00
100100
150150
200200
250250
00 11 22 3 hr3 hr
Time After NicotineTime After Nicotine
% o
f B
as
al
Re
lea
se
% o
f B
as
al
Re
lea
se
AccumbensAccumbensCaudateCaudate
NICOTINENICOTINE
Time After Methamphetamine
% B
as
al
Re
lea
se
METHAMPHETAMINE
0 1 2 3hr
1500
1000
500
0
Accumbens
What Can Imaging Tell What Can Imaging Tell Us?Us?
In design of In design of new medications new medications – knowledge – knowledge of affected circuitry can point to of affected circuitry can point to chemical chemical dysfunction dysfunction that may be helped by that may be helped by medication.medication.
In the design of In the design of behavioral treatments behavioral treatments it it can tell you the can tell you the types and severity of types and severity of deficits deficits and dysfunctions in the brain and and dysfunctions in the brain and the the timetable of their recovery timetable of their recovery (or not). (or not). This information can be helpful in guiding This information can be helpful in guiding the behavioral targets for treatment and the behavioral targets for treatment and the types and durations of treatment that the types and durations of treatment that can best accommodate the brain recovery can best accommodate the brain recovery
Brain imaging can show Brain imaging can show how much viable how much viable tissue tissue there is to work with. And, it can there is to work with. And, it can show the show the affect of treatmentaffect of treatment..
Imaging ModalitiesImaging Modalities
Regional FunctionRegional Function Specific Specific NeurochemistryNeurochemistry
PETPET MetabolismMetabolism
Blood FlowBlood FlowNeurotransmitterNeurotransmitters & their s & their ReceptorsReceptors
SPECTSPECT Blood Flow “poor-Blood Flow “poor-mans PET”mans PET”
NeurotransmitterNeurotransmitters & their s & their ReceptorsReceptors
MRIMRI Correlates of Correlates of Blood FlowBlood Flow
1.1. SpectroscopySpectroscopy
2.2. Diffusion Diffusion Tensor Tensor ImagingImaging
Brain Function in Brain Function in Methamphetamine Methamphetamine AbusersAbusers Do METH abusers show Do METH abusers show
abnormalities in brain abnormalities in brain metabolitesmetabolites??
Do brain metabolite abnormalities Do brain metabolite abnormalities relate to cognitive performancerelate to cognitive performance – – such as selective attention?such as selective attention?
Does the brain Does the brain recover following recover following cessationcessation of METH use? of METH use?
Prolonged Drug Use ChangesProlonged Drug Use Changesthe Brain In Fundamentalthe Brain In Fundamentaland Long-Lasting Waysand Long-Lasting Ways
Source: McCann U.D.. et al.,Journal of Neuroscience, 18, pp. 8417-8422, October 15, 1998.
Decreased dopamine Decreased dopamine transporter binding in METH transporter binding in METH users resembles that in users resembles that in Parkinson’s Disease Parkinson’s Disease
Control Meth PD
Partial Recovery of Brain Dopamine Transporters in
MethamphetamineAbuser After Protracted
Abstinence
Normal Control METH Abuser(1 month detox)
METH Abuser(24 months detox)
0
3
ml/gm
Source: Volkow, ND et al., Journal of Neuroscience 21, 9414-9418, 2001.
Meth
Meth
Meth
Meth
Their Brains
have been
Re-Wired by Drug Use
Their Brains
have been
Re-Wired by Drug Use
Because…Because…
Some Recent FindingsSome Recent Findings
Methamphetamine abusers have Methamphetamine abusers have deficits in:deficits in:
prefrontal cortex prefrontal cortex ((working working memorymemory) Edythe London et al) Edythe London et al
anterior cingulate gyrus anterior cingulate gyrus ((selective selective attentionattention) Nordahl, Salo et al, Salo, ) Nordahl, Salo et al, Salo, Nordahl et al, Taylor et alNordahl et al, Taylor et al
temporal lobe temporal lobe ((episodic memory, episodic memory, depression)depression) London et al London et al
SpeculationSpeculation
Cognitive deficits in Cognitive deficits in methamphetamine abusers are methamphetamine abusers are likely to reflect damage in likely to reflect damage in anterior brain regions, such as anterior brain regions, such as anterior cingulum, that anterior cingulum, that could could contribute tocontribute to their clinical their clinical presentation of presentation of inattention and inattention and distractibilitydistractibility. .
Control > MA
4
3
2
0
1
MA > Control
5
4
2
0
1
3
Cognitive and Cognitive and
Memory EffectsMemory Effects
Differences between Stimulant and Differences between Stimulant and Comparison Groups on tests Comparison Groups on tests requiring perceptual speedrequiring perceptual speed
0
20
40
60
80
100
Mea
n S
core
s
Digit Symbol** Trail Making A* Trail Making B**
Stimulant (n=80) Comparison (n=80
Memory Difference between Memory Difference between Stimulant and Comparison Stimulant and Comparison GroupsGroups
0
1
2
3
4
5
6
7
Mea
n S
core
s
Word Recall** Picture Recall**
Comparison (n=80) Meth (n=80)
Longitudinal Memory Longitudinal Memory PerformancePerformance
test
num
ber
corr
ect
0
5
10
15
20
25
Word Recall WordRecognition
Picture Recall PictureRecognition
controlbaseline3 mos6 mos
% I
mpair
ed
0
10
20
30
40
50
60
0
10
20
30
40
50
60ControlsMA Users
Learningand
Memory
Frequency of Impairment by Neuropsychological Domain
Attention/Psychomotor
Speed
WorkingMemory
Fluency Inhibition
Executive Systems Function
Defining Domains:Defining Domains: Executive Systems Executive Systems FunctioningFunctioning a.k.a. frontal lobe functioning.a.k.a. frontal lobe functioning. Deficits on executive tasks assoc. Deficits on executive tasks assoc.
w/:w/:– Poor judgment.Poor judgment.– Lack of insight.Lack of insight.– Poor strategy formation.Poor strategy formation.– Impulsivity.Impulsivity.– Reduced capacity to determine Reduced capacity to determine
consequences of actions.consequences of actions.
Brain Serotonin Transporter Brain Serotonin Transporter Density and Aggression in Density and Aggression in Abstinent Methamphetamine Abstinent Methamphetamine AbusersAbusers
Sekine, Y, Ouchi, Y, Takei, N, et al. Brain Serotonin Transporter Sekine, Y, Ouchi, Y, Takei, N, et al. Brain Serotonin Transporter Density and Aggression in Abstinent Methamphetamine Density and Aggression in Abstinent Methamphetamine Abusers. Abusers. Arch Gen Psychiatry.Arch Gen Psychiatry. 2006;63:90-100. 2006;63:90-100.
Objective of StudyObjective of Study
Investigate the status of brain Investigate the status of brain serotonin neurons and their serotonin neurons and their possible relationship with clinical possible relationship with clinical characteristics in currently characteristics in currently abstinent methamphetamine abstinent methamphetamine abusers.abusers.
ResultsResults 1.1. Serotonin transporter density in global brain Serotonin transporter density in global brain
regions was significantly lower in regions was significantly lower in methamphetamine abusersmethamphetamine abusers
• Suggests that abuse of methamphetamine Suggests that abuse of methamphetamine leads to a leads to a global and severe reductionglobal and severe reduction in in the density of human brain the density of human brain serotonin serotonin transporterstransporters
2.2. Values of serotonin transporter density in Values of serotonin transporter density in widely distributed brain regions were found widely distributed brain regions were found to negatively correlate with the duration of to negatively correlate with the duration of methamphetamine use.methamphetamine use.
• Suggests that Suggests that the longerthe longer methamphetamine is used, methamphetamine is used, the more the more severesevere the decrease in serotonin the decrease in serotonin transporter density.transporter density.
Results (Continued)Results (Continued)3.3. Magnitude of aggression Magnitude of aggression in methamphetamine abusers in methamphetamine abusers
increased significantly increased significantly with decreasing serotonin with decreasing serotonin transporter densitiestransporter densities in some brain regions. in some brain regions.
• Bitofrontal cortex, anterior cingulate, temporal cortexBitofrontal cortex, anterior cingulate, temporal cortex
4.4. No correlationNo correlation between a representative measure of between a representative measure of serotonin transporter density and the serotonin transporter density and the duration of duration of methamphetamine abstinencemethamphetamine abstinence. Individuals abstinent . Individuals abstinent for > 1 year still had a substantial decrease in for > 1 year still had a substantial decrease in serotonin transporter density.serotonin transporter density.
• Suggests reductions in the density of the serotonin Suggests reductions in the density of the serotonin transporter in the brain transporter in the brain could persist long after could persist long after methamphetamine use ceasesmethamphetamine use ceases..
Methamphetamine Use, Self-Reported Methamphetamine Use, Self-Reported Violent Crime, and Recidivism Among Violent Crime, and Recidivism Among Offenders in California Who Abuse Offenders in California Who Abuse Substances Substances
Cartier J, Farabee D, Prendergast M. Methamphetamine Use, Cartier J, Farabee D, Prendergast M. Methamphetamine Use, Self-Reported Violent Crime, and Recidivism Among Offenders Self-Reported Violent Crime, and Recidivism Among Offenders in California Who Abuse Substances. in California Who Abuse Substances. Journal of Interpersonal Journal of Interpersonal Violence.Violence. 2006;21:435-445. 2006;21:435-445.
Objective of StudyObjective of Study
Examine the associations Examine the associations between methamphetamine (MA) between methamphetamine (MA) use and three measures of use and three measures of criminal behavior: (a) self-criminal behavior: (a) self-reported violent criminal reported violent criminal behavior, (b) return to prison for a behavior, (b) return to prison for a violent offense, and (c) return to violent offense, and (c) return to prison for any reason.prison for any reason.
MethodsMethods ParticipantsParticipants
– 808 low- to medium-level inmates808 low- to medium-level inmates Clear history of substance abuseClear history of substance abuse Within 12 months of releaseWithin 12 months of release Half the sample entering an in-prison Half the sample entering an in-prison
substance abuse (SA) program and the substance abuse (SA) program and the other half from a neighboring prison other half from a neighboring prison that offered no formal SA treatmentthat offered no formal SA treatment
Matched by age, ethnicity, sex Matched by age, ethnicity, sex offender status, and commitment offender status, and commitment offenseoffense
Methods ContinuedMethods Continued
• Baseline and 12-Month Follow-Up Baseline and 12-Month Follow-Up InterviewsInterviews Modified versions of criminal justice Modified versions of criminal justice
treatment evaluation forms developed by treatment evaluation forms developed by researchers at Texas Christian Universityresearchers at Texas Christian University
Sections on sociodemographic Sections on sociodemographic background, family and peer relations, background, family and peer relations, health and psychological status, criminal health and psychological status, criminal involvement, in-depth drug-use history, involvement, in-depth drug-use history, and an AIDS-risk assessmentand an AIDS-risk assessment
ResultsResults
Those who used MA (81.6%) were Those who used MA (81.6%) were significantly more likely than significantly more likely than those who did not use MA (53.9%) those who did not use MA (53.9%) to have been to have been returned to custodyreturned to custody for any reason or to for any reason or to report report committing any violent actscommitting any violent acts in the in the 30 days prior to follow-up (23.6% 30 days prior to follow-up (23.6% vs. 6.8%, respectively)vs. 6.8%, respectively)
Results ContinuedResults Continued
After controlling for drug trade After controlling for drug trade involvement, MA use was still involvement, MA use was still significantly significantly predictive of self-predictive of self-reported violent crimereported violent crime and and general recidivismgeneral recidivism
Implications of ResultsImplications of Results
• These findings suggest that These findings suggest that offenders who use MA may differ offenders who use MA may differ significantly from their peers who do significantly from their peers who do not use MA and may require not use MA and may require more more intensive treatment interventionsintensive treatment interventions and and parole supervisionparole supervision than other than other types of offenders who use drugstypes of offenders who use drugs
Neural Activation Patterns of Neural Activation Patterns of Methamphetamine-Methamphetamine-Dependent Subjects During Dependent Subjects During Decision Making Predict Decision Making Predict Relapse Relapse
Paulus M, Tapert S, Schuckit M. Neural Activation Paulus M, Tapert S, Schuckit M. Neural Activation Patterns of Methamphetamine-Dependent Subjects Patterns of Methamphetamine-Dependent Subjects During Decision Making Predict Relapse. During Decision Making Predict Relapse. Arch Gen Arch Gen Psychiatry.Psychiatry. 2005;62:761-768. 2005;62:761-768.
Objective of StudyObjective of Study
To determine whether functional To determine whether functional magnetic resonance imaging magnetic resonance imaging (fMRI) during a decision-making (fMRI) during a decision-making task can be used to predict task can be used to predict relapse in treatment-seeking relapse in treatment-seeking methamphetamine-dependent methamphetamine-dependent individuals individuals
MethodsMethods ParticipantsParticipants
– 46 treatment-seeking males46 treatment-seeking males Met criteria for current dependence on Met criteria for current dependence on
methamphetamine (MA)methamphetamine (MA) Not dependent on any other drug or on Not dependent on any other drug or on
alcoholalcohol Voluntarily entered and completed a 28-Voluntarily entered and completed a 28-
day inpatient programday inpatient program At the time of scanning, abstinent from MAAt the time of scanning, abstinent from MA
Methods ContinuedMethods Continued• Interview-based symptomatic Interview-based symptomatic
assessmentassessment• fMRI tasksfMRI tasks
2-choice prediction task2-choice prediction task Response taskResponse task
• Outcome measureOutcome measure Blood oxygen level-dependent fMRI Blood oxygen level-dependent fMRI
activation during tasksactivation during tasks
Methods ContinuedMethods Continued Follow-UpFollow-Up
– Contacted 1 year after imaging Contacted 1 year after imaging sessionsession
– Sobriety assessed using a Sobriety assessed using a questionnairequestionnaire
– Relapse defined as any use of MA Relapse defined as any use of MA during any time after dischargeduring any time after discharge
ResultsResults 18 of 40 subjects relapsed18 of 40 subjects relapsed
Bilateral prefrontal cortex, Bilateral prefrontal cortex, striatum, posterior parietal striatum, posterior parietal cortex, and anterior insula were cortex, and anterior insula were more active duringmore active during the the prediction task than the prediction task than the response taskresponse task
Results ContinuedResults Continued 9 areas within these regions 9 areas within these regions
differentiateddifferentiated relapsing and relapsing and nonrelapsing participantsnonrelapsing participants– Areas included prefrontal, parietal, Areas included prefrontal, parietal,
and insular cortexand insular cortex– Nonrelapsing individuals showed Nonrelapsing individuals showed
more activation in these areasmore activation in these areas
Results ContinuedResults Continued– Right insula, right posterior cingulate, Right insula, right posterior cingulate,
and right middle temporal gyrus and right middle temporal gyrus response best differentiated between response best differentiated between relapsing and nonrelapsing participantsrelapsing and nonrelapsing participants Cross-validation analysis was able to Cross-validation analysis was able to
correctly predict 19 of 22 who did not correctly predict 19 of 22 who did not relapse and 17 of 18 who relapsedrelapse and 17 of 18 who relapsed
– Right middle frontal gyrus, right middle Right middle frontal gyrus, right middle temporal gyrus, and right posterior temporal gyrus, and right posterior cingulate cortex activation best cingulate cortex activation best predicted time to relapsepredicted time to relapse
Implications of ResultsImplications of Results
• Neural activation differences are part of a Neural activation differences are part of a system involved with the system involved with the processing of processing of decision makingdecision making. Attenuated activation may . Attenuated activation may represent:represent: Defective assessment abilitiesDefective assessment abilities and and
subsequent reliance on habitual behaviorssubsequent reliance on habitual behaviors Diminished Diminished ability to differentiate choices ability to differentiate choices
that lead to good vs. poor outcomesthat lead to good vs. poor outcomes• fMRI may prove to be a useful clinical tool to fMRI may prove to be a useful clinical tool to
assess relapse susceptibilityassess relapse susceptibility
Methamphetamine Abuse, HIV Methamphetamine Abuse, HIV Infection Causes Changes in Brain Infection Causes Changes in Brain StructureStructureJernigan,T, et al American Jnl of Psychiatry Aug Jernigan,T, et al American Jnl of Psychiatry Aug 20052005 Methamphetamine abuse and HIV infection Methamphetamine abuse and HIV infection
cause significant cause significant alterations in the size of alterations in the size of certain brain structurescertain brain structures, and in both cases the , and in both cases the changes may be associated with impaired changes may be associated with impaired cognitive functions, such as cognitive functions, such as difficulties in difficulties in learning new informationlearning new information, , solving problemssolving problems, , maintaining attention maintaining attention and quickly and quickly processing processing informationinformation..
Co-occurring methamphetamine abuse and Co-occurring methamphetamine abuse and HIV infection appears to result in HIV infection appears to result in greater greater impairment impairment than each condition alone than each condition alone
Methamphetamine Abuse, HIV Methamphetamine Abuse, HIV Infection Causes Changes in Brain Infection Causes Changes in Brain StructureStructureJernigan,T, et al American Jnl of Psychiatry Aug Jernigan,T, et al American Jnl of Psychiatry Aug 20052005
Brain scans to analyze structural volume changes in Brain scans to analyze structural volume changes in 103 adults divided among four populations103 adults divided among four populations: : methamphetamine abusers who were HIV-positive; methamphetamine abusers who were HIV-positive; methamphetamine abusers who were HIV-negative; methamphetamine abusers who were HIV-negative; nonabusers who were HIV-positive; and nonabusers nonabusers who were HIV-positive; and nonabusers who were HIV-negative. who were HIV-negative.
They also assessedThey also assessed the the ability to think and reasonability to think and reason using a detailed battery of tests that examined using a detailed battery of tests that examined speed of information processing, attention/working speed of information processing, attention/working memory, learning and delayed recall, memory, learning and delayed recall, abstraction/executive functioning, verbal fluency, abstraction/executive functioning, verbal fluency, and motor functioning.and motor functioning.
Methamphetamine Abuse, HIV Methamphetamine Abuse, HIV Infection Causes Changes in Brain Infection Causes Changes in Brain StructureStructureJernigan,T, et al American Jnl of Psychiatry Aug Jernigan,T, et al American Jnl of Psychiatry Aug 20052005
Methamphetamine abuse is associated with changes Methamphetamine abuse is associated with changes in the the brain’s parietal cortex (which helps people in the the brain’s parietal cortex (which helps people to to understand and pay attention to what’s going on understand and pay attention to what’s going on around themaround them) and basal ganglia () and basal ganglia (linked to motor linked to motor function and motivationfunction and motivation). ).
The degree of change in the parietal cortex was The degree of change in the parietal cortex was associated with worse cognitive function associated with worse cognitive function
HIV infection is associated with prominent volume HIV infection is associated with prominent volume losses in the cerebral cortex (losses in the cerebral cortex (involved in higher involved in higher thought, reasoningthought, reasoning, and , and memorymemory), basal ganglia, and ), basal ganglia, and hippocampus (hippocampus (involved in memory and learninginvolved in memory and learning))
Methamphetamine Abuse, HIV Methamphetamine Abuse, HIV Infection Causes Changes in Brain Infection Causes Changes in Brain StructureStructureJernigan,T, et al American Jnl of Psychiatry Aug Jernigan,T, et al American Jnl of Psychiatry Aug 20052005
““In HIV-infected people, the cognitive impairments In HIV-infected people, the cognitive impairments are associated with are associated with decreased employment and decreased employment and vocational abilitiesvocational abilities, , difficulties with medication difficulties with medication managementmanagement, , impaired driving impaired driving performance, and performance, and problems with general problems with general activities of daily livingactivities of daily living, , such as managing money,” such as managing money,”
““The impact of methamphetamine could The impact of methamphetamine could potentially potentially affect treatment and relapse affect treatment and relapse prevention prevention efforts, as well as things like efforts, as well as things like money money management management and and driving driving performance.”performance.”
Methamphetamine Abuse, HIV Methamphetamine Abuse, HIV Infection Causes Changes in Brain Infection Causes Changes in Brain StructureStructureJernigan,T, et al American Jnl of Psychiatry Aug Jernigan,T, et al American Jnl of Psychiatry Aug 20052005
YoungerYounger methamphetamine abusers methamphetamine abusers showed showed larger effectslarger effects in some brain regions. in some brain regions.
Among HIV-infected individuals, the Among HIV-infected individuals, the researchers noted a direct researchers noted a direct association association between the severity of the infection and between the severity of the infection and greater loss of brain mattergreater loss of brain matter. .
In methamphetamine abusers who are also In methamphetamine abusers who are also HIV-positive, decreased volumes are HIV-positive, decreased volumes are correlated with correlated with increased cognitive increased cognitive impairment in one brain regionimpairment in one brain region, the , the hippocampus. hippocampus.
For more information, contact:For more information, contact:
Thomas E. Freese, Ph.DThomas E. Freese, Ph.D..310-445-0874 x304310-445-0874 x304
[email protected]@ix.netcom.com
