Theories and Philosophies of Addiction: Towards a New Model

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

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

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

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

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

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. 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. 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

17. The structure of human motivation

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

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

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

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

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. Nicotine and the central reward pathway • 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

25. Usually strongest in 1 week Usually last between 1 and 4 weeks Usually last at least 12 weeks Usually last between 1 and 4 weeks Usually permanent 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)

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

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. 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. Summary of treatment effectiveness