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A contemporary perspective on drug abuse

A contemporary perspective on drug abuse. Terry Bazzett Department of Psychology SUNY Geneseo. Reinforcement as a Biological Concept. Why do people abuse drugs?. Drug abuse seems counterintuitive. Health problems Social problems Relationship problems Financial problems

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A contemporary perspective on drug abuse

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  1. A contemporary perspective on drug abuse Terry Bazzett Department of Psychology SUNY Geneseo

  2. Reinforcement as a Biological Concept

  3. Why do people abuse drugs? • Drug abuse seems counterintuitive. • Health problems • Social problems • Relationship problems • Financial problems • From a biological perspective it is intuitive. • Our brains reinforce useful behaviors • The brain does not distinguish between useful behaviors and drug use.

  4. Neural pathways control behaviors • The nigrostriatal pathway controls movement

  5. Neural pathways control behaviors • The mesolimbic pathway reinforces behavior

  6. Neural pathways reinforce behaviors • The mesolimbic pathway is “designed” to • Reinforce useful behaviors • Reinforce naturally occurring behaviors • This is a perfectly good design • Useful behaviors can be bypassed • Using electrical stimulation • Using drugs • This is abuse of a perfectly good design

  7. Dopamine… a common denominator • The mesolimbic pathway uses dopamine (DA) • Drugs of abuse typically stimulate DA pathways • In general, reinforcement is correlated with DA activity • Drugs that inhibit DA are not pleasurable

  8. Secondary effects • While DA reinforcement is the primary driving force for drug use, other effects contribute. • Depressants for those who are anxious • Stimulants for those who want greater arousal • Hallucinogens for those who want altered experiences • Opiates for those who want sedation • Etc.

  9. Drug abuse as a Biological Concept

  10. 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.

  11. 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)

  12. What is down-regulation

  13. What is down-regulation • Decrease in transmitter release (rapid) • Decrease in receptor sensitivity (slower) • Decrease in receptor sites (slower)

  14. The down side of down-regulation • Once down regulation occurs, a vicious cycle begins. • More drug is required to feel intoxication • More drug use results in greater down-regulation • A down-regulated reinforcement circuit means • Increases in drug are needed • Pleasure in natural reinforcers is decreased

  15. Double your pleasure, double your fun

  16. Compensating for down-regulation • When a system becomes less responsive: • You can increase your drug dose • Combine drugs to potentiate effects • Combine drug with arousing behavior (e.g. sex) • Each of these has its own risks

  17. Increasing drug dose • Primary risk of overdose • Secondary economical problems • Secondary side-effect problems

  18. Combining drugs • Sometimes used to potentiate DA while also compensating for secondary effects • Speedball as example of a deadly combination • Many other combinations may be used

  19. Combining drugs and sex • Combining a DA releasing behavior with a DA stimulating drug potentiates effects • Many drugs impair cognitive function, leading to risky sex behavior

  20. Pick your poison… the classics

  21. Alcohol • The misnomer of “drugs and alcohol”. • Alcohol is a drug • Highly addictive • Extremely potent • Deadly… overdose, accidents, combined with other drugs • Deadly… withdrawal

  22. Alcohol – Biology • Indirectly enhances DA systems • Alcohol enhances GABA activity • Increased GABA activity = relaxation • Most anti-anxiety drugs also increase GABA • Many people self-medicate with alcohol • GABA down-regulation • Results in anxiety in the absence of alcohol • In extreme cases withdraw = seizures/death

  23. Alcohol – the great social stimulant • The cortex actively inhibits impulsive behavior • GABA activation inhibits this inhibition • Alcohol reduces ability to control impulsive behavior • Impulsive behaviors • Driving while drunk • Unprotected sex • Consuming additional drugs (including alcohol)

  24. 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

  25. Pick your poison… the classics

  26. Stimulants • Includes cocaine, amphetamine, Ritalin, etc • Highly addictive • Highly reinforcing • Intense cravings • Relatively mild physical withdrawal

  27. Stimulants – Biology • Directly enhance DA activity • Also increase norepinephrine (NE) = excitation • Increased NE = awake and alert • Some people self-medicate with stimulants • Most people use stimulants to enhance the party • DA and NE down-regulation • Results in depression/lethargy when drug not used • These symptoms increase craving/desire for drug

  28. 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

  29. Pick your poison… the classics

  30. Opiates • Includes morphine, codeine, heroin, oxycodone, suboxone (buprenorphine), etc. etc. etc. • Highly addictive • Highly reinforcing • High cravings • Moderate physical withdrawal

  31. Opiates: Not just a “street drug” "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 “I am addicted to prescription pain medication.” -- Rush Limbaugh show, Oct 10, 2003

  32. Opiates – Biology • Indirectly enhances DA systems • Directly enhance endogenous opiate systems • Sedation • Extreme analgesia • Some claim reduction of “emotional pain” • DA and opiate down-regulation • Results in depression/pain when drug not used • These symptoms increase craving/desire for drug

  33. Opiates– treating addiction • Down regulated DA system may require antidepressant drugs • Opiate withdrawal can be tempered with methadone • Methadone is another opiate system stimulant • Methadone treatment creates it’s own problems • Cold turkey is difficult because of cravings, but not typically dangerous

  34. Pick your poison… the classics

  35. Marijuana • Smoked or ingested orally • Not particularly addictive • Not particularly reinforcing • Relatively mild cravings • Mild physical withdrawal

  36. 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 used • These symptoms increase desire for drug

  37. Marijuana – treating addiction • Down regulated DA system may require antidepressant drugs • Anti-anxiety drugs may be prescribed • Cold turkey is typical for this drug

  38. When good mice go bad. • Visit the mouse party for fun information

  39. Pick your poison… the new wave

  40. MDMA – Ecstasy • 3,4-methylenedioxy-N-methylamphetamine • Increases serotonin, DA, and NE release • Considered a stimulant • But… many variations exist • Lack of control in manufacturing • amphetamine, methamphetamine, ephedrine, caffeine, are all cheaper substitutes

  41. MDMA – Biology • Comparatively little known about dependence • Withdrawal often accompanied by dysphoria • Studies indicate neurotoxic effects • Serotonin and DA neurons degenerate in animals • Too soon to know about long-term human effects • Some concern about early life sub-threshold loss

  42. Pick your poison… the new wave

  43. MEPH/MDPV – Bath Salts • Key ingredients • MEPH (Mephedrone) • MDPV (methylenedioxypyrovalerone) • But… as with MDMA • Cheaper variations may exist • All components likely to have stimulant effects

  44. MEPH/MDPV – Biology • MEPH • Enhances release of DA • May enhance release of other transmitters • MDPV • Blocks re-uptake (deactivation) of transmitter after it has been released • This is an effect similar to cocaine • Agitation, anxiety, overdose can cause death

  45. Pick your poison… the new wave

  46. Salvia Divinorum • Currently not illegal • Little research exists on effects • Addictive potential seems low • Little or no effect on brain DA (?) • Concerns over use still exist Salvia smoking video

  47. Salvia Divinorum - Biology • Binds to opioid receptor sites • Response similar to serotonin hallucinogens

  48. 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 individuals • Predisposed individuals are most inclined to use • Myocardial Infarction has been reported in several young healthy users

  49. Spice/K2 - Biology • Binds to cannabinoid receptor sites • Very little is known beyond this…

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