Psychology of Addiction
(The models)
The disease model
 Neurotransmitters
 The chemical that moves
between nerve cells to
transmit messages.
 If the message is blocked
or replaced there will be
a change to the
physiological system and
this in turn will effect
mood behaviour and
cognition.
The disease model-Dopamine.
 Dopamine is the most commonly
associated neurotransmitter
with addiction.
 Dopamine is similar to adrenaline
in that it affects brain
processes that control
movement, emotional response,
and ability to experience
pleasure and pain.
 Cocaine and other drugs of
abuse can alter dopamine
function
Some drugs are known as dopamine agonists.
These drugs bind to dopamine receptors in place of dopamine &
directly stimulate those receptors.
The disease model- Dopamine.
 Drugs such as cocaine and amphetamine produce their effects
by changing the flow of neurotransmitters. These drugs are
defined as indirect acting because they depend on the activity
of neurons.
 In contrast, some drugs bypass neurotransmitters altogether
and act directly on receptors. Such drugs are direct acting.
Thinking point: At this point think about the role of dopamine in
relation to addiction e.g. what about gambling/gaming...could
you describe how dopamine can be used as a viable theory to
explain these addictions?
 However, some drugs increase dopamine by preventing dopamine
reuptake, leaving more dopamine in the synapse.
 An example is the widely abused stimulant drug, cocaine.
Another is methylphenidate, used therapeutically to treat
childhood hyperkinesis and symptoms of schizophrenia.
The disease model-Genetics
Scientists will never find just one single addiction gene.
Susceptibility to addiction is the result of many interacting genes
Dr Glen Hanson suggests:
 "Just because you are prone
to addiction doesn't mean
you're going to become
addicted. It just means
you've got to be careful."
 Researchers construct
pedigrees of large families
with addiction as a first step
to understanding the disease.
 A pedigree can reveal
whether or not a trait has a
genetic component. That is,
whether or not it is passed
down from parent to child by
way of genes
Using pedigree data, researchers can begin to hunt down genes.
They begin by comparing DNA sequences of individuals who have the disease
with those who do not. They can then narrow down the possibilities to identify a
small number of so-called "candidate genes" for addiction.
Source:http://learn.genetics.utah.edu/content/addiction/genetics/
Glen Hanson cont…
 There are many ways that genes could cause one person
to be more vulnerable to addiction than another.
1. Starting addictive behaviour.
2. Continuing with additive behaviour.
3. Activating the reward system.
4. Feelings of pleasure.
1. There could well be a specific gene for each! Remember:
Scientists will never find just one single addiction gene.
Susceptibility to addiction is the result of many
interacting genes
2. Like other behavioural diseases, addiction vulnerability
is a very complex trait. Many factors determine the
likelihood that someone will become an addict
The story of John & James.
 John Crawford has an
identical twin. His 16-yearold brother, James, is his
mirror image. John has
brown hair, brown eyes,
and a slightly crooked
smile. So does James.
John weighs about 160
pounds. Ditto for James.
The brothers walk the
same, talk the same—their
friends tease them
because they even bowl
the same.
The reason, of course, is that identical twins share exactly the same genes,
those tiny units of hereditary material (DNA) that carry instructions for forming
all the cells in the body and directing their activity.
Can addiction run in families? Let us
assume John & James have a parent who struggles with alcoholism
 Q: Are they destined by genetics to face the same fate?
 A: The good news is that no single factor determines whether a person will
become addicted to drugs. That’s because genetics, biology, and environment all
influence a person’s risk for addiction, defined as a chronic yet treatable brain
disease characterized by compulsive seeking and use.
 So, while the saying may be that substance abuse in particular “runs in the
family,” a whole list of other risk factors in addition to genes come into play to
determine whether a person gets hooked.
 Genetics
 Age,
 Presence of other diseases,
 Diet
 Stress,
 Peer pressure.
Genetics aka addictive inheritance
 Separates the genetic and environmental factors
of addictive behaviour.
 Studies have been done to control for
environmental components to determine if genetics
plays a greater role.
 Most studies looking at alcoholism have determined
that children born from alcoholic parents who are
adopted into non-alcoholic families have a three to
four fold increase in the rate of alcoholism over
the rest of the population.
 Indeed, children born and raised by alcoholic
parents have an even greater rate of alcoholism.
This suggests that there is some genetic
predisposition to alcoholic addiction.
Several questions we must consider at
this point.
 Is it the addictive behaviour that is encoded or a
biological mechanism that drives the behaviour?
 Are there differences in the metabolism of various
addictive substances that allow an individual to have
varying levels of a drug in the blood stream and have
a psychological experience different someone else?
 Is there some genetic difference that perhaps allows
some to realise when an elevated blood alcohol level
has been reached and transmits a message to the
brain to stop drinking that others do not have?
Things that make you go hmm??
What evidence is available….
 The strongest correlation between addiction and genetics
comes when evaluating the pattern of inheritance. All
studies show that it is sons, not daughters, who most
often inherit the risk of alcoholism.
You should at this point be critically analysing the findings by thinking…..
Could it be that sons
model themselves more
after their fathers? .
How much of this
phenomenon has
its basis in
genetics.
Or is there a sexlinked genetic
mechanism at play
that is
contributing to
this phenomenon?
Further evidence…
1. A study using 300 MZ twins
& approx 200 DZ twins
estimated the contribution
of genetic factors &
environmental factors to
substance use in
adolescence.
 Findings:
 Major influence on the
decision was environmental
rather than genetic (Hans et
al 1999)
2. Link between personality &
addictive behaviour.
 300 MZ & 300 DZ looked at
relationship between alcohol
use & personality.
 Findings:
 Connection between genetics
& anti social personality
characteristics & between
personality changes &
alcoholism (Jang et al 2000)
3. Comings et al (1996) also found similar
findings in the investigation looking into behavioural addictions such as gambling
Let us review…….
So far we have learned there are
several components to addiction and
that defining addiction has not always
been easy. We have begun to look at the
disease model of addiction and have
discussed the role of neurotransmitters
& genes.
Now would be a good time to check our
understanding…..
Over to you: In pairs answer the following
questions on your mini whiteboards.
 According to Griffiths
(2005), what are the six
components of addictive
behaviour?
 What neurotransmitter is
most commonly associated
with addictive behaviour and
why?
Usual rules apply!
 Why are twin studies a good
method for examining the
role of genetics in addictive
behaviour.
You have 10 mins to complete this task.
Q: What about the effects of
reinforcement?..Isn't that behaviourism?
 A: Technically yes!!!
 The rule/definition:
Anything that increases
the probability of a
behaviour occurring in
similar circumstances.
Reinforcement & biology! There is a crossover!
 Think classical & operant
conditioning.....think pleasure
centres in the brain.
 Research 1: Olds & Milner
(1954) discovered rats would
press a lever for the reward
of mild electrical stimulation
in specific areas of the
brain. They also pressed the
lever for stimulation of
other rewards such as food
or sexual activity.
Plug ‘em in + Rat + Shock = Pleasure. = A type of reinforcement...there
is our tedious link!!
Things that make you go hmmm!!!
 Pleasure is an
 These feelings act as
important factor in
reinforcers...therefore
healthy development. pleasure encourages
Would you eat
essential behaviours or
McDonalds/Chocolat
in some cases unhealthy
e again if it were not behaviours......we all
pleasurable?
have our crosses to
bear..Is addiction is
the price we pay??
Evaluation of biological
explanations.
Foes
Friends
 Biological explanations help
explain disposition.
Helps to account for
Vulnerabilities &
susceptibilities' and also
provides information on why
some may relapse more than
others.
Don't forget other
evaluative points too!
Method, Ethics, AID,
Keywords etc.
 Neurotransmitters complex
effects are not fully
understood. Which
neurotransmitters produces
which reward? Nicotine can
effect memory & learning and
increase arousal but reduce
stress...thus difficult to pinpoint
exactly what is going on!!!
 Social interaction is underrated.
Social contexts- The
pleasures/escapism..depending
on the context Vietnam soldiers
took drugs but stopped when
back home (Robins et al 1975)
 Genotypes are not the full story.
Emphasis on genetics rather
than environment.
Cognitive explanations of addictive
behaviour.
Faulty Thinking
 Example= Gambling
 “I will win, I can control
the odds, if I use my
lucky numbers I'll be
rich one day.”
Irrational biases
 Overestimate the
extent to which they
can predict or influence
the outcomes. This also
leads to a under
estimation of how much
has been lost/won.
 See Griffiths (1994)
Gamblers irrational
cognitive biases.
Evaluation of cognitive explanation
Friends
Foes
 Skill perception varies across
 Helps explain individual
individuals Cannot establish cause &
differences During
effect because skill is not consistent
development of maintenance
among gamblers or irrational.
stage faulty biases may be
more likely to develop
problems.
 Experiential factors play a role too.
Many gamblers on automatic
pilot..suggesting cognitive processes
did not play major role in maintenance
of behaviour.
 Cognitive explanations may be limited
to specific addictions May have less
of an effect in chemical addicitions
such as Heroin but better in
understanding gambling.
How do Heuristics apply to addictions
e.g. gambling
 Rule of thumb :The usual rules apply.
 Hindsight Bias:’I knew that would happen’
 Flexible attribution:’I’m really good at Blackjack, I
lost on the roulette because of the other bloke’
 Absolute frequency bias:’I dont thinkl about the
losses...I won loadsa money.....’
Availability bias: Look how many people
have won the lottery....loads!!
In review....
Components of addiction....Check
Models of addiction....Check
Biological/Cognitive.....Check
 A little of behavioural too....a little check!
Evaluation of two models...Check
Try these questions to check your
understanding so far...in pairs on
whiteboards..10 mins.
 What are heuristics & why do they helps us
understand addictive behaviour?
 Outline three criticisms of biological
approach o addictive behaviour?
 Outline three criticisms of cognitive
approach to addictive behaviour