1. 1 Theories and Philosophies of Addiction: Towards a New Model University College London 2009 Robert West

2. 2 Outline Prevailing theories of addiction Basics of PRIME Theory Predictions and new evidence

3. 3 Outline Prevailing theories of addiction Basics of PRIME Theory Predictions and new evidence

4. 4 Rational decision making Theory –Addiction involves making a rational choice that favours the benefits of the addictive behaviour over the costs Evidence –Many addicts perceive life as better with their addictive behaviour –Incentives and disincentives are quite effective in modifying addictive behaviours Limitations –Poor at predicting relapse following decisions to cease the addictive behaviour

5. 5 Irrational decision making Theory –Addiction involves an irrational choice that inflates the benefits and/or undervalues the costs Evidence –Addicts exhibit cognitive and motivational biases that promote the addiction ( e.g. attentional and memory biases, short-termism) Limitations –No evidence to date that such biases actually influence the course of addictive behaviours

6. 6 Biological needs Theory –Addiction involves development of physiological needs which are met by the addictive behaviour Evidence –Addicts report aversive withdrawal symptoms and drive states which deter abstinence –Medication that relieves these needs and drive states improve chances of abstinence Limitations –Relapse is frequent even in absence of withdrawal symptoms or drive states

7. 7 Psychological needs Theory –Addictive behaviour meet psychological needs Evidence –Individuals with psychological needs (e.g. depression, anxiety) met by addictive behaviours are more likely to become addicted and less likely to recover Limitations –Many addicts show no evidence of psychological needs prior to developing addiction –Psychological health often improves following a period of abstinence

8. 8 Pleasure and reward Theory –Addictive behaviours are particularly pleasurable or rewarding Evidence –Almost all addictions provide pleasure or satisfaction, often to a high degree Limitations –Many long-term addicts report little or no pleasure from the addiction –Degree of pleasure in at least some addictions is not correlated with probability of relapse

9. 9 Habit Theory –Addiction involves the development of strong automatic stimulus-response associations Evidence –At least some addictive behaviour shows evidence of automaticity Limitations –Much addictive behaviour shows evidence of involving conscious choice

10. 10 Social and physical environment Theory –Environmental factors are important in development and recovery from addiction Evidence –Clear effects of ‘contagion’, opportunity, environmental triggers, and social facilitation on development and recovery from addiction Limitations –Internal and genetic factors have also been shown to be important

11. 11 Prevailing theories: summary Each approach explains some observations but fails to explain others In practice, interventions aimed at combating addiction draw from multiple theories and ‘common sense’

12. 12 Outline Prevailing theories of addiction Basics of PRIME Theory Predictions and new evidence

13. 13 Where does motivation fit in? Response control system Response generation system Cognitive system Sensory system Skill Motivation Memory and inference Information acquisition Skill Motivation Memory and inference Skill Motivation Information acquisition Cognition Skilled Motivation Each system can operate in isolation but is usually strongly under the influence of other systems Response control system Response generation system Cognitive system Response control system Response generation system Information acquisition system Mental representation system Response control system Response generation system Skilled Motivation Information acquisition Skilled Motivation Skilled Motivation Sensation Skill Motivation

14. 14 PRIME Theory An attempt at a theory of motivation that puts into a single model diverse features –plans and self-control –analytical decision making –emotional decision making and drives –habits and instinctive responses Uses as few concepts as possible Uses a language as close to everyday use as possible Biologically plausible

15. 15 Key assumptions Structure of the motivational system –Humans have evolved a motivational systems with multiple levels (PRIME) –Higher levels allow greater flexibility of response and future-orientation but can only influence behaviour through lower levels Function of the motivational system –The system is fundamentally unstable requiring constant ‘balancing input’ to prevent development of maladaptive dispositions –All behaviour is subject to motivations acting ‘in the moment’

16. 16 The structure of the motivational system p Plans r Responses i Impulses m Motives e Evaluations Five interacting subsystems providing varying levels of flexibility and requiring varying levels of mental resources and time Higher level subsystems have to act through lower level ones where they compete with direct influences on these

17. 17 The structure of human motivation

18. 18 PRIME Responses –starting, stopping or modifying actions –arise from the strongest of potentially competing impulses and inhibitions –measured by observation self-report

19. 19 PRIME Impulses and inhibitions –arise from strongest of potentially competing learned and unlearned stimulus-impulse/inhibition (SI) associations (habit and instinct) motives

20. 20 PRIME Motives –wants (feelings of anticipated pleasure/satisfaction) or needs (feelings of anticipated relief) –arise from reminders interacting with past experiences of pleasure/satisfaction and pain/discomfort/drive states evaluations

21. 21 PRIME Evaluations –beliefs about what is good or bad –arise from reminders motives inference communication plans

22. 22 PRIME Plans –intentions to carry out actions in the future –Arise from evaluations reminders interacting with stored plans

23. 23 Cigarette addiction and nicotine dependence Smokers experience powerful feelings of urge or need to smoke which overwhelm and undermine their resolve not to This is because nicotine acts as both a positive and negative reinforcer: –Positive reinforcement: nicotine acts on the reward pathways in the brain generating urges to smoke in the presence of smoking cues –Negative reinforcement nicotine causes chronic changes to the brain resulting in a need to smoke to alleviate: –‘nicotine hunger’ when CNS concentrations are depleted –aversive withdrawal symptoms

24. 24 Nicotine binds to nicotinic acetylcholine receptors in the Ventral Tegmental Area This increases NDMA- initiated burst firing of the mesolimbic dopamine pathway This increases release of dopamine in the Nucleus Accumbens Nicotine and the central reward pathway

25. 25 Problems experienced during cessation –Urges to smoke –Mood disturbance Irritability Depression Anxiety Restlessness –Difficulty concentrating –Increased appetite –Physical symptoms Increased cough Constipation Mouth ulcers Weight gain (mean 6-8kg) Usually strongest in 1 week Usually last between 1 and 4 weeks Usually last at least 12 weeks Usually permanent Usually last between 1 and 4 weeks

26. 26 Principles underlying effective interventions Promoting a quit attempt –increase desire to stop now by 1.increasing feelings of concern 2.boosting confidence in success 3.providing a route for immediate action Effective methods of quitting 1.minimise desire to smoke 2.maximise desire not to smoke 3.increase self-regulatory capacity and skills 4.promote optimal use of medications

27. 27 Brief advice from a physician Target group –All smokers attending surgeries The intervention –Ask about smoking and history or quitting; Advise to stop; Assist by referring to Stop Smoking Service or giving prescription Type of evidence –Multiple randomised controlled trials Effect –Increases the rate at which smokers try to stop and the success rates in those that try –Causes 2% of smokers to stop >6 months

28. 28 Behavioural support for quit attempts Advice, discussion and exercises designed to: –maximise and sustain motivation not to smoke –minimise motivation to smoke –increase self-regulatory capacity and skills –optimise use of smoking cessation medications

29. 29 Summary of treatment effectiveness