Why do people smoke and find it so hard
to stop?
Robert West
University College London
November 2008
1
Outline
1.
2.
3.
4.
5.
Why do people do anything?
Why do people smoke?
What does stopping doing something mean?
Why is it hard to stop doing anything?
Why is it hard to stop smoking?
2
Why do people do anything?
• We:
– act on impulse
• we do it without thinking about the consequences
– want or need something
• we seek a source of pleasure or satisfaction, or of relief
– think it is right or will serve a purpose
• we do what we consider best
– are following a plan
• we act on a prior intention
• And this motivation is stronger than any
competing motivation present at the time
3
Example
• Faced with an apparent thief running towards us on the
street:
–
–
–
–
–
the impulse is to avoid physical contact (‘flinch’)
there may be anticipation of satisfaction from catching a criminal
there may be anticipation of harm from being attacked
there may be a belief that one should be a good citizen
there may be a prior generalised intention to fight crime where
possible
• Conflict between these different types of motivation will
determine what action is taken ‘in the moment’
4
The requirement
• To develop a model that describes how different
types of motivation interact and compete to
generate responses ‘in the moment’
5
A solution
• A motivational system with 5 levels, with higher levels
feeding into lower levels
– Responses
• starting, stopping or modifying actions
– Impulses vs inhibition
• Activation of CNS pathways underpinning actions, and competing
pathways inhibiting them (urges)
– Motives
• Mental representations of future world states with feelings of
anticipated pleasure or satisfaction (wants) or relief (needs)
– Evaluations
• Beliefs involving sense of what is useful/harmful (functional),
right/wrong (moral), pleasing/displeasing (aesthetic)
– Plans
• Mental representations of future actions associated with feeling of
varying degrees of commitment (intentions and rules)
6
The structure of the motivational system
Five interacting subsystems providing varying levels of flexibility
and requiring varying levels of mental resources and time
p
Plans
r
Responses
i
Impulses
m
Motives
e
Evaluations
Higher level subsystems have to
act through lower level ones
where they compete with direct
influences on these
7
Key points
1. Our behaviour is motivated at multiple levels from
impulses, motives and evaluations to plans
2. Higher level motivations must work through lower level
ones where they may come into conflict with other
motivations at that level
3. Plans have a vital role to play in organising our
behaviour and protecting our longer term interests in
the face of immediate demands
4. But implementing them in the face of conflicting wants,
needs and urges is effortful and uses up mental
resources
8
Why do people smoke?
• They light up and puff on impulse
– much smoking is ‘habitual’, done without thinking
• They want or need to
– they expect to enjoy it; they experience a ‘hunger’ for a cigarette
after a period of not smoking
• They think it serves a purpose
– they expect it to help with stress, weight control and
concentration
• They form plans to smoke
– they have a routine of going for a cigarette during coffee breaks
• These motivations are stronger than any competing
motivations including a plan not to smoke
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How does this arise?
• Nicotine ‘hits’ from each puff of a cigarette binds to
nicotinic acetylcholine receptors in the brain causing:
– dopamine release in the nucleus accumbens which:
• generates an automatic impulse to smoke in the presence of
smoking cues
• provides pleasure and satisfaction associated with smoking
• makes other experiences associated with smoking more
pleasurable
• changes the functioning of the brain region concerned so that when
CNS nicotine levels are depleted there is need to smoke to restore
those levels (nicotine hunger)
– other chronic changes to brain chemistry resulting in
• adverse mood and physical symptoms such as anger, depression
and difficulty concentrating generate an additional need to smoke
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What does stopping doing something mean?
•
Self-consciously stopping doing something
typically means:
1. forming a rule (plan) not to do it, or
2. forming a rule (plan) that one will ‘try’ not to do it
•
Applying that rule in relevant situations which
generates a want or need not to do it
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Why is it so hard to stop doing anything?
• To stop ourselves doing something that is
habitual or we want or need to do, our rule must
generate more powerful competing wants and
needs
• This is difficult if:
– the impulse, want or need to engage in the behaviour
is at least sometimes strong and/or
– our capacity to generate competing wants or needs
when required is weak
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Why is it so hard to stop smoking?
• The impulse to smoke
– Many smokers experience powerful cue-driven impulses in
situations in which they would normally smoke
• The want to smoke
– Many smokers enjoy and get satisfaction from smoking
• The need to smoke
– ‘Nicotine hunger’, adverse effects of abstinence
• Positive beliefs about smoking
– Stress relief, aid to concentration, weight control
• The routine of smoking
– Strong over-learned plans to smoke at certain times
13
Rates of attempting to stop smoking
Rate of attempts to stop in past
year
50
40
Percent
• Rate of attempts to stop
decreases with age
• Data from 4374 adults
aged 16+ who smoked in
the past year in Smoking
Toolkit Study, surveyed in
2008
30
20
10
0
15
25
35
45
55
65
75
Age
14
Success rates of unaided quit attempts
Prognosis curve
100
90
80
70
60
50
40
30
20
10
0
Percent who will succeed
long term
Percent still abstinent
Relapse curve
0
10
20
30
40
100
90
80
70
60
50
40
30
20
10
0
0
50
10
20
30
40
50
Weeks since quit date
Weeks since quit date
The need to smoke decreases rapidly
after the first week, but can re-emerge
months or years later
Weekly relapse rate
Weekly relapse rate
100
90
80
70
60
50
40
30
20
10
0
0
10
20
30
40
50
Weeks since quit date
15
Wanting and needing to smoke
• Wanting to smoke
appears to deter attempts
to stop while needing to
smoke leads to relapse
once an attempt is made
Urges to smoke
90
85
Percent
80
75
70
65
60
55
50
Did not attempt
Percent
Data from 1479 smokers
in Smoking Toolkit
Study, followed up 6
months after ratings or
enjoyment and urges
were made to find out
whether: had attempted
to stop and if so had
relapsed
Enjoyment of smoking
Strong urges
Relapsed
No urges
100
95
90
85
80
75
70
65
60
55
50
Did not
attempt
Enjoy
Relapsed
Not enjoy
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Tackling the problem at all levels: reducing
motivation to smoke
• Reduce the impulse
– medication during smoking to break the smoking-reward link
– reduce exposure to smoking cues
• Reduce the want and need
– medication during smoking and abstinence to make smoking
less satisfying and reduce nicotine hunger and adverse
symptoms
– control exposure to events that provoke wanting and needing
• Change beliefs
– convince smokers that smoking does not confer benefits
• Change plans
– change routines that involve smoking
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Tackling the problem at all levels: increasing
motivation not to smoke
• Generate competing impulses
– set up competing habitual responses to smoking cues
• Increase the want and need not smoke
– use extrinsic rewards and punishments (e.g. social approval,
disapproval, vouchers)
– maintain salience of negative feelings about smoking (e.g,
disgust, anxiety)
– foster intrinsic rewards for not smoking (e.g. achievement)
• Change beliefs
– foster negative beliefs about smoking and positive non-smoker
identity
• Establish firm, coherent plans
– Establish clear ‘not a puff’ rule as part of new identity
– Establish clear if-then rules to minimise wants, needs and urges
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Conclusions
1. Our actions are controlled by multiple levels of a motivational
system (PRIME) with higher levels (plans) having to work
through lower levels (impulses and inhibitions)
2. At every moment there may be conflict between motivations
arising from the same or different levels
3. Stopping doing something involves forming a rule (plan)
which has to generate sufficiently strong wants and needs to
overpower more immediate wants, needs and urges rising at
a lower level
4. Stopping smoking is hard because of powerful urges, wants
and needs arising from the actions of nicotine in the brain
5. The optimum solution requires attending to all levels of the
motivational system to minimise the motivation to smoke and
maximise the motivation not to at all times
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