a contemporary perspective on drug abuse
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A contemporary perspective on drug
abuse
Terry BazzettDepartment of Psychology
SUNY Geneseo
Reinforcement as a Biological Concept
Why do people abuse drugs? Drug abuse seems counterintuitive.
Health problemsSocial problemsRelationship problemsFinancial problems
From a biological perspective it is intuitive.Our brains reinforce useful behaviorsThe brain does not distinguish between useful
behaviors and drug use.
Neural pathways control behaviors The nigrostriatal pathway controls movement
Neural pathways control behaviors The mesolimbic pathway reinforces behavior
Neural pathways reinforce behaviors The mesolimbic pathway is “designed” to
Reinforce useful behaviorsReinforce naturally occurring behaviorsThis is a perfectly good design
Useful behaviors can be bypassedUsing electrical stimulationUsing drugsThis is abuse of a perfectly good design
Dopamine… a common denominator The mesolimbic pathway uses dopamine (DA)
Drugs of abuse typically stimulate DA pathwaysIn general, reinforcement is correlated with DA activityDrugs that inhibit DA are not pleasurable
Secondary effects While DA reinforcement is the primary driving
force for drug use, other effects contribute.Depressants for those who are anxiousStimulants for those who want greater arousalHallucinogens for those who want altered experiencesOpiates for those who want sedationEtc.
Drug abuse as a Biological Concept
Why not enjoy drugs? If drugs stimulate a natural system, what’s the
harm in enjoying them?For occasional recreational use, probably nothing.When use becomes heavy or persistent, problems
may arise.○ Drugs are generally more potent than natural
reinforcers ○ Drugs are “easier” than natural reinforcers○ The reinforcement pathway may down-regulate.
What is down-regulation Biological systems strive for homeostasis When systems are highly active, the body
responds by decreasing activity. Down-regulation is part of the biological
basis for drug tolerance (habituation)
What is down-regulation
What is down-regulation Decrease in transmitter release (rapid) Decrease in receptor sensitivity (slower) Decrease in receptor sites (slower)
The down side of down-regulation Once down regulation occurs, a vicious cycle begins.
More drug is required to feel intoxicationMore drug use results in greater down-regulation
A down-regulated reinforcement circuit meansIncreases in drug are neededPleasure in natural reinforcers is decreased
Double your pleasure, double your fun
Compensating for down-regulation
When a system becomes less responsive:You can increase your drug doseCombine drugs to potentiate effectsCombine drug with arousing behavior (e.g. sex)
Each of these has its own risks
Increasing drug dose Primary risk of overdose
Secondary economical problemsSecondary side-effect problems
Combining drugs Sometimes used to potentiate DA while also
compensating for secondary effects Speedball as example of a deadly combinationMany other combinations may be used
Combining drugs and sex Combining a DA releasing behavior with a
DA stimulating drug potentiates effectsMany drugs impair cognitive function, leading to
risky sex behavior
Pick your poison… the classics
Alcohol The misnomer of “drugs and alcohol”.
Alcohol is a drug○ Highly addictive○ Extremely potent○ Deadly… overdose, accidents, combined with
other drugs○ Deadly… withdrawal
Alcohol – Biology Indirectly enhances DA systems Alcohol enhances GABA activity Increased GABA activity = relaxation
Most anti-anxiety drugs also increase GABAMany people self-medicate with alcohol
GABA down-regulation Results in anxiety in the absence of alcoholIn extreme cases withdraw = seizures/death
Alcohol – the great social stimulant The cortex actively inhibits impulsive behavior
GABA activation inhibits this inhibitionAlcohol reduces ability to control impulsive
behaviorImpulsive behaviors
○ Driving while drunk○ Unprotected sex○ Consuming additional drugs (including alcohol)
Alcohol – treating addiction Down regulated GABA treated with
benzodiazapines (anti-anxiety meds). Down regulated DA system may require
antidepressant drugs Cold turkey is ill-advised
Pick your poison… the classics
Stimulants Includes cocaine, amphetamine, Ritalin, etc
Highly addictiveHighly reinforcingIntense cravingsRelatively mild physical withdrawal
Stimulants – Biology Directly enhance DA activity Also increase norepinephrine (NE) =
excitationIncreased NE = awake and alertSome people self-medicate with stimulantsMost people use stimulants to enhance the party
DA and NE down-regulation Results in depression/lethargy when drug not usedThese symptoms increase craving/desire for drug
Stimulants – treating addiction Down regulated DA system may require
antidepressant drugs Lethargy has to be waited out Cold turkey is difficult because of cravings, but
not typically dangerous
Pick your poison… the classics
Opiates Includes morphine, codeine, heroin,
oxycodone, suboxone (buprenorphine), etc. etc. etc.Highly addictiveHighly reinforcingHigh cravingsModerate physical withdrawal
Opiates: Not just a “street drug”
“I am addicted to prescription pain medication.” -- Rush Limbaugh show, Oct 10, 2003
"If (Surgeon General Jocelyn Elders) wants to legalize drugs, send the people who want to do drugs to London and Zurich, and let's be rid of them. -- Rush Limbaugh show, Dec 9, 1993
Opiates – Biology Indirectly enhances DA systems Directly enhance endogenous opiate systems
SedationExtreme analgesiaSome claim reduction of “emotional pain”
DA and opiate down-regulation Results in depression/pain when drug not usedThese symptoms increase craving/desire for drug
Opiates– treating addiction Down regulated DA system may require
antidepressant drugs Opiate withdrawal can be tempered with
methadone Methadone is another opiate system stimulantMethadone treatment creates it’s own problems
Cold turkey is difficult because of cravings, but not typically dangerous
Pick your poison… the classics
Marijuana Smoked or ingested orally
Not particularly addictiveNot particularly reinforcingRelatively mild cravingsMild physical withdrawal
Marijuana – Biology Indirectly enhances DA activity Directly stimulates cannabinoid receptors
Anandamide is our “endogenous marijuana”Functions are unknown… guesses?
DA and Cannabinoid down-regulation Mild depression/anxiety when drug not usedThese symptoms increase desire for drug
Marijuana – treating addiction Down regulated DA system may require
antidepressant drugs Anti-anxiety drugs may be prescribed Cold turkey is typical for this drug
When good mice go bad.
Visit the mouse party for fun information
Pick your poison… the new wave
MDMA – Ecstasy 3,4-methylenedioxy-N-methylamphetamine
Increases serotonin, DA, and NE releaseConsidered a stimulant
But… many variations existLack of control in manufacturingamphetamine, methamphetamine, ephedrine,
caffeine, are all cheaper substitutes
MDMA – Biology Comparatively little known about dependence
Withdrawal often accompanied by dysphoria Studies indicate neurotoxic effects
Serotonin and DA neurons degenerate in animalsToo soon to know about long-term human effectsSome concern about early life sub-threshold loss
Pick your poison… the new wave
MEPH/MDPV – Bath Salts Key ingredients
MEPH (Mephedrone) MDPV (methylenedioxypyrovalerone)
But… as with MDMA Cheaper variations may existAll components likely to have stimulant effects
MEPH/MDPV – Biology MEPH
Enhances release of DAMay enhance release of other transmitters
MDPVBlocks re-uptake (deactivation) of transmitter after
it has been releasedThis is an effect similar to cocaineAgitation, anxiety, overdose can cause death
Pick your poison… the new wave
Salvia Divinorum Currently not illegal Little research exists on effects
Addictive potential seems lowLittle or no effect on brain DA (?)
Concerns over use still existSalvia smoking video
Salvia Divinorum - Biology Binds to opioid receptor sites Response similar to serotonin hallucinogens
Spice/K2 – synthetic cannabis Currently not illegal Herbs mixed with synthetic cannabinoids
Synthetic cannabinoids have unknown effects Concerns over use
Can trigger psychosis in predisposed individualsPredisposed individuals are most inclined to useMyocardial Infarction has been reported in several young
healthy users
Spice/K2 - Biology Binds to cannabinoid receptor sites Very little is known beyond this…
Pick your poison… the new wave
Alkyl nitrites – Poppers Very little research…
Considered to have stimulant effectsSome analgesic properties?Some ability to relax striated muscles?
Variants are used to treat anginaAmyl nitrite… similar compound, similar effects
Little (no) addictive potential
Alkyl nitrites – Biology Blood vessel dilation, increased heart rate
Brain effects are unclear Retinal toxicity has also been reported
Users need to be aware of possible damage to visual system
Theories of Addiction
“Just say no”… a flawed campaign
It’s easy to say “no” when you’re…In your 60sMarried to the President of the United StatesA millionaire
Reasons to say “yes” to drugs When natural reinforcement is hard to come by
Drugs are cheap Drugs require little effortSocial acceptance may come with drug useDrugs can make you feel like a millionaire married
to the President of the United States. Swansea Love Story (loud)
What is drug addiction? Currently debated
Cravings more than physical dependenceTendency to relapseContinued use in the face of harm
No “typical” progressionBut certain stages are commonSome progressions paths are likely/unlikelySome users may “mature out”
8.4 The continuum of drug use
Models of Addiction Physical Dependence model
Drugs thwart withdrawal symptoms Positive Reinforcement model
Like bar pressing rat… we learn drugs=euphoriaLearned behavior persists with down-regulation
Liking and Wanting modelOne brain system “likes” drugs (reinforcement)
and down-regulatesOne brain system “wants” drugs (?) and does not
down-regulate
Models of Addiction Disease model
Some physiological susceptibilitySusceptibility worsens with repeated exposureThere are possible genetic factors
Biopscyosocial modelIt is difficult to deny any of these factors as
possible contributorsThis is the most comprehensive model
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