Psychobiology of Addiction

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Psychobiology of Addiction

• Lecture 1
• Introduction and some basic concepts

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Seminar Groups

• Group 1 Jelena Nesic Pev II 4B11 phone 7106
• Group 2 Sophie George JMS 5D10 phone 2952
• Group 3 Julie LeMerrer JMS5D phone 2763
• Group 4 Abi Rose Pev II 4B7 phone 6561
• Group 1 Friday 12.00 - 14.00 BSMS 2.10.
• Group 2 Tuesday 11.00 12.50 MANT-1A1
• Group 3 Monday 16.00 - 17.50 Arts D610
• Group 4 Wednesday 11.00 - 12.50 Arts D510

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Trends in drug use in Europe cocaine
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WHAT IS ADDICTION?
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The heroin addictfrom Goldsteins Addiction
from Biology to Drug Policy

• A 50 year old man gets of the bus in a seedy down
  town neighborhood. Just hours before, he was
  released after serving a 2 year sentence for
  burglary, his third time in prison. His regular
  income as a grocery clerk had been barely enough
  to support his wife and child, so burglary seemed
  the only way to raise the large sums he needed
  for his heroin habit.
• Watch him! Only a block from the bus terminal, he
  makes his connection, buys a needle and
  syringe, and some white powder. Heroin put him
  in prison three times. Heroin will surely finish
  him off. Why doesnt he quit? Why didnt he quit
  25 years ago when he could see clearly what his
  future would be if he continued using heroin?

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The nicotine addictfrom Goldsteins Addiction
from Biology to Drug Policy

• A 50-year old man lies in a hospital bed,
  desperately ill. Emphysema has destroyed his
  lugs, and the pitiful sound of his laboured
  breathing fills the room. Watch him! Incredible
  as it seems, he begs his wife to buy him some
  cigarettes. Cigarettes put him here, cigarettes
  will surely finish him off. Why doesnt he quit?
  Why didnt he quit 25 years ago when the first
  surgeon-generals report on smoking, widely
  publicised, had already made it clear what his
  future would be if he continued his pack a day
  habit?

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Addiction

• A syndrome in which the use of a drug is given a
  much higher priority than other behaviors that
  once had higher value.
• In its extreme form addiction is associated
  with compulsive drug using behavior and it
  exhibits the characteristics of a chronic
  relapsing disorder

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• Drug Abuse - The use, usually by
  self-administration of any drug in a manner which
  deviates from the approved medical or social
  patterns within a given culture
•  
• N.B. this definition is largely social and varies
  across societies, and within societies at
  different times
•        chronic intoxication with alcohol is
  considered abuse the occasional gross
  intoxication is not.
•        the use of medically-prescribed opioid
  analgesics for the relief of pain is quite
  proper the use of the same drugs in the same
  doses for the relief of depression or tension, or
  to induce euphoria is considered abuse

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Drug dependence -
Physical dependence is manifested by biochemical,
physiological and/or behavioral disruptions that
occur on termination of drug treatment RR
Griffiths and CA Sannerud (1987)   Dependence is
a state implicitly assumed to have led to the
appearance of behavioural changes (psychological
dependence) and/or physiological changes
(physical dependence) on withdrawal of the drug M
Lader (1988)  
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Drug dependence -
Physical dependence has usually been defined in
terms of the withdrawal syndrome observed upon
cessation of chronic drug administration.
......it is generally theorized to be a
consequence of adaptive changes in drug affected
tissue systems which compensate for, and produce
tolerance to the direct effects of the drug. JD
Roache (1990)  A state, psychic and sometimes
also physical, which results from the interaction
between a living organism and a drug, which is
characterised by behavioral and other responses
that always include compulsion to take the drug
on a continuous or periodic basis in order to
experience its psychic effects and sometimes to
avoid the discomfort of its absence. Tolerance
may be present. World Health Organisation, 1977
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Physiological dependence The state which can
be inferred if withdrawal of the drug leads to
physiological signs and symptoms of withdrawal.
  Psychic dependence The psychological state
which occurs following repeated drug experience
and reveals itself as a desire to take the
drug.   N.B. Whereas physiological dependence
can be measured independently of drug taking, and
can therefore be used as an explanation of
addiction, psychic dependence is defined in terms
of the phenomenon such as craving and compulsive
drug taking that define addiction. It therefore
has no explanatory value.
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• Physical dependence and drug abuse are not
  necessarily associated
• Avoidance of a withdrawal syndrome cannot explain
  initiation of drug taking
• Some abused drugs do not produce physical
  dependence
• Some drugs give rise to withdrawal symptoms, but
  are not abused
• Some abusers of dependence-inducing drugs are not
  physically dependent
• Relapse to drugs occurs months or years after
  withdrawal symptoms are over.

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Withdrawal avoidance theories of drug
addiction People take drugs in order to avoid the
negative consequences of withdrawal
Positive incentive theories of drug
addiction the primary cause of addiction is the
craving for the positive effects of the
drug Stewart, de Wit and Eikelboom, 1984
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Craving
Drug craving is the desire for previously
experienced effects of a psychoactive substance.
This idea can become compelling and can increase
in the presence of both internal and external
cues, particularly with substance availability.
It is characterised by an increased likelihood of
drug seeking behaviour and, in humans, of
drug-related thoughts.   (United Nations
International Drug Control Programme World
Health Organisation)
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Craving   Jellinek (1955, 1960) craving is
the essential defining characteristic of
alcoholism and can be used to explain the
initiation and maintenance of compulsive alcohol
consumption as well as relapse to alcohol use
after a peroid of abstinence.   This view fell
into disfavour for two reasons   1) abstinent
alcoholics did not necessarily engage in loss of
control of drinking when they consumed small
amounts of alcohol. Since Jellinek assumed that
craving mediates between initial consumption and
loss of control, the absence of such a pattern
casts doubt on the need for such a
construct.   2) Behavioural approaches to the
study of addiction eschewed such mentalistic
approaches as craving as explanatory constructs.
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Craving
 the intense desire for drug  a sign the
addict has a problem to solve, e.g. that the drug
is not available  Question is craving an
essential part of drug taking?  the
psychological processes controlling drug use can
operate independently of those that control urge
responding.   ......craving represents the
activation of effortful cognitive processing
devoted to impeding or abetting the execution of
automatic drug use behaviour Tiffany Psychol
Revs (1990)
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Genesis of drug use and dependence

• Experimentation with drugs may depend on
•          social acceptability of a given form of
  drug use
•          availability
•          attitude and drug-using behaviour of
  friends
•          tendency of individual to seek out
  novel situations and to respect social norms

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Traditional View of the Natural History of Drug
Dependence

• People take drugs for the first time because of
  peer pressure, opportunity, etc.
• As a result of drug acting within the body,
  homeostatic interactions take place, which serve
  to reduce the effects of the drug - tolerance
• As a result, in the absence of the drug, the body
  functions less than optimally, so that the person
  is driven to take drugs to restore optimal
  function

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The addictive process involves adaptations at
many levels

• In the stage of controlled drug use, as a result
  of curiosity, peer pressure, social factors,
  personality traits etc. the subject comes into
  contact with a drug with addictive liability
  (Social Psychology Personality).
• Drugs act at particular systems in the brain
  (Pharmacology) to achieve a rewarding effect
• The reinforcing properties of the drug
  (Psychology) facilitate further exposure to the
  drug while its ability to facilitate Pavlovian
  incentive learning related to release of DA in
  the NAc shell (Behavioural Neuroscience),
• amplified by an individual sensitivity of DA
  release in the NAc shell (Neuroscience) promote
  the acquisition of incentive stimuli predictive
  of drug availability (Behavioural Neuroscience).
• In this stage the subject responds to the drug
  and to drug-related stimuli in a controlled
  manner not dissimilar from normal motivated
  responding.

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The addictive process involves adaptations at
many levels

• With repeated drug exposure the subject
  progressively enters the stage of drug abuse.
• In this stage the repeated association of drug
  reward and drug-related stimuli in the presence
  of a non-habituating stimulation of DA
  transmission in the NAc shell results in the
  attribution of excessive motivational value to
  drug-associated stimuli (Psychology).
• In this stage the subject can still control drug
  intake in the absence of drug-related stimuli.
• Their presence, however, elicits drug-seeking
  eventually associated to mild drug urges
  (craving) (Psychology).
• Sensitization of NAc core DA responsiveness
  (Neuroscience) might start already during this
  stage and continue through the following one.

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The addictive process involves adaptations at
many levels

• The stage of addiction is characterized by the
  condition of the preceding stage to which is
  added that of tolerance and dependence of DA
  transmission in the NAc shell.
• In this stage, abstinence results in a negative
  emotional state (Psychology) that maintains the
  motivational relationship between the subject and
  the drug in the intervals when drug-conditioned
  incentives are not available.
• Moreover, associative learning mechanisms
  (Psychology) related to the action of the drug
  are amplified and strengthened during abstinence
  as a result of a potentiation of the DA releasing
  properties of the drug.
• In the post-addiction stage, abstinence symptoms
  progressively disappear
• but Pavlovian associations remain as powerful
  incentives for reinstatement of drug
  self-administration (Psychology Learning
  theory).

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LEVELS OF EXPLANATION   Synaptic
modification Compensatory responses in the neural
system Behavioural Adaptation Personality Social
factors Legal aspects Political aspects  
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Abuse Potential of different drugs according to
different criteria for abuse, listed in
descending order