Addiction pathophysiology


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  • Welcome… introduce yourself
  • Smokers report smoking as a lifestyle choice like lack of exercise and an unhealthy diet, but research on nicotine and its effects on the brain show that it results in addiction and dependence. A state often not recognised by the smoker.
  • Smoking is the leading preventable risk to New Zealander’s health, and therefore must be a priority for GP’s interested in improving the health of their practice population. Still one in four New Zealand adults smoke.
  • Smokers are desperate to quit across all age groups, roughly 70% have made a quit attempt in the last five years.
  • Why don’t smokers stop? How exactly does nicotine keep them hooked?
  • What is meant by addiction, from a behavioural point of view, it is a loss of control, mediated by subconscious neural mechanisms. These criteria are taken from the DSM-IV criteria for substance misuse. As illustrated by the background photograph, the lack of control of tobacco use can persist despite severe negative health consequences, including the amputation of both forearms.
  • Nicotine from cigarette smoke, travels to the brain, diffuses through the blood brain barrier, and activates the reward pathways in the mid-brain to activate dopamine release in the brain pleasure centre (nucleus accumbens).
  • Nicotine acts on a specific acetylcholine receptor in the brain, that stimulates dopamine release in the mid brain. Cues, such as the sight of others smoking, coffee or cigarette packets can lead to strong urges to smoke. The pleasure felt after eating food uses the same neural pathway, and this is why smokers put on an average of 3.5kg after quitting, presumably using food to diminish craving for cigarettes. Interestingly, glucose tablets, used by diabetics to control hypoglycemia, can also be used by smokers to switch off craving.
  • The nicotine ‘hit’ gives a feel good factor mediated by dopamine release, and the behaviours that lead to this hit are strongly re-inforced. This is likely to be a less important mechanism than negative re-inforcement, as smoking does not provide an intense hit, in comparison to other drugs, such as cocaine.
  • Many smokers are under the illusion that smoking gives them pleasure, however, most smoke to avoid unpleasant withdrawal symptoms; like slipping out of tight shoes.
  • Ask the audience - What are the symptoms of nicotine withdrawal? How long do they last? We have all experienced withdrawal at some time or another. Believe it or not 50% of regular coffee drinkers experience withdrawal when abstinent. Think back to the last time you had to work night shift. What do you start craving during the night? Does your mood and ability to concentrate help? Prompt the audience to respond before removing the graphic. Mention that most people just don’t feel quite right until they have a cigarette. Emphasise that these withdrawal symptoms are generally gone by the first month and diminish the longer the patient is able go without a cigarette.
  • Smoke is inhaled into the lungs, down the large airways to the alveoli, where the nicotine passes rapidly into the blood stream, and is transported, via the left side of the heart to the brain. Nicotine crosses the blood-brain barrier and disperses to the neurons of the mid brain – the nucleus accumbens – to stimulate acetyl choline receptors that lead to dopamine release, and results in stimulation of the reward centre in the brain, leading to the high most smokers experience after a puff. Eventually, in a smokers brain, the acetyl choline receptors are up-regulated and less sensitive to nicotine, inducing tolerance. The repeated stimulation by nicotine re-inforces behaviours that are associated with smoking. The continued activation of this centre by nicotine from cigarettes leads to re-inforcement of any behaviour associated with smoking – called cues. These can be having a coffee in the morning, seeing another person light up, after dinner, or with a beer. These cues provoke sub-conscious urges to smoke, that bypass conscious centres and hence the smoker lights up another one often without thinking about it!
  • This strategy describes the guts of the recent New Zealand Smoking Cessation guidelines, to guide clinicians in their decisions to help smokers.
  • Smoking cessation is straight forward. Your main role is to ask, give brief advice and offer support, whether you yourself offer it, or you refer to others who can.
  • Another example of brief advice, with a personal health issue inserted, such as improved asthma, child’s health, risk of heart attack, improved wound healing after surgery, improved fertility etc. The treatment options may include NRT, support yourself or by your practice nurse, or quitline (telephone support).
  • Emphasise the positive benefits of quitting
  • There is a broad spectrum of behavioural support that can be offered to patients, depending on your time and confidence with the area
  • Firstly, lets look at which strategies are more effective for your patients
  • NRT does not deliver nicotine in the same way as a cigarette, and therefore will not completely relieve craving – it does help, but is not a magic cure. Gum and patch give a much slower and lower peak concentration of NRT than cigarettes, and hence do not give the same intense ‘hit’.
  • Within 30 minutes – combination treatment, start with high dose and assess in 1 week Less than 30 minutes – prn gum, reassess in 1/52 Most often, under dosing rather than over dosing is the problem.
  • A reminder not to forget the chew/park/chew method for using gum.
  • Treating smokers is not usually a “one-off” consultation. Encourage smokers to see you (or practice nurse) at weekly intervals. Discuss successes and failures; praise successes, and review withdrawal symptoms, cravings and possible problems with NRT. Remember most smokers will not be using enough. Ongoing craving, weight gain etc can be attributed to this.
  • NRT is safe, even in patients with established cardiovascular disease. They will get less nicotine than from smoking, without being exposed to the harmful carcinogens, carbon monoxide and volatile organic compounds. Discuss importance of discussing risks and benefits in pregnancy. Weight of opinion favours use in pregnancy over smoking, though no strong evidence.
  • Self explanatory- Good analogy – quitting without NRT is like going to the dentist and not having local anaesthetic!
  • What practical advice can you give your smoker? Explain the importance of NRT, setting a definite quit day and preparing for it by removing access to cigarettes and enlisting support from family members. Explain how addiction is like a monster on your shoulder. Cigarettes feed it, but diminished by time without cigarettes. Help the smoker enlist friends to help and ask about cues to smoke, and help them develop plans to deal with these. Also encourage them to develop a new identity as a non-smoker. Common myths need to be debunked, many smokers are suspicious of NRT, and need to be reassured that although it keeps them hooked, it is not the component of tobacco smoke that harms their health. Many want to quit cold turkey, so that the addiction is not maintained, however, a helpful comparison is using NRT to quit, in much the same way as local anaesthetic assists with a trip to the dentist, but doesn’t take away all the pain etc. Although cutting down can be a step toward the ultimate goal of quitting, it should not be seen as sufficient to improve health. Explain that most smokers are not able to cut down long term, and will return to their current level of smoking unless they ultimately quit.
  • Addiction pathophysiology

    1. 1. What makes sane people do crazy things? Addiction: the individual perspective Dr Simon Thornley
    2. 2. Aims/objectives <ul><li>To understand modern medical perspectives of addiction and motivation, using smoking as an example </li></ul><ul><li>To understand what interventions help people to overcome addictions </li></ul><ul><li>To consider a novel subject, sugar consumption, from an addiction perspective. </li></ul>
    3. 3. My story <ul><li>Parents as committed smokers </li></ul><ul><li>Hospital doc </li></ul><ul><li>Caffeine </li></ul><ul><li>Nicotine studies / withdrawal symptoms </li></ul><ul><li>Obesity and food and scientific backlash </li></ul>
    4. 4. Quiz <ul><li>What addictive drug does the most damage to health? </li></ul><ul><ul><li>Heroine, cocaine, P, alcohol, cigarettes. </li></ul></ul><ul><li>What element of tobacco smoke damages health? Nicotine or Tar </li></ul><ul><li>What is thought to be the main reason that people smoke? Pleasure or normality </li></ul><ul><li>How do you best know how addicted someone is to cigarettes? CPD or TTFC? </li></ul>
    5. 5. Your experiences with addiction <ul><li>In pairs, discuss one episode over the last 6 months, inwhich you felt you were affected by either your own or someone else’s addiction. </li></ul><ul><li>What happened? </li></ul><ul><li>Did you try and improve the situation? </li></ul><ul><ul><li>If so, how? </li></ul></ul>
    6. 6. Letter to the Herald <ul><ul><li>“ Smokers are not always rational. I discovered this at an early age when travelling in the car with my parents. A ritual of protest would unfold as my brothers and I would plead with them to abstain from smoking during the trip. Inevitably, our voices would be drowned out by my parents’ desire to quench their tobacco withdrawal with a freshly lit cigarette.” </li></ul></ul>
    7. 7. Smoking: an addiction?
    8. 8. Is smoking a problem for health?
    9. 9. Who wants to quit?
    10. 10. WHY DO PEOPLE SMOKE?
    11. 11. <ul><li>Use more than intended  </li></ul><ul><li>Difficulty quitting  </li></ul><ul><li>Priority over social activities  </li></ul><ul><li>Use despite harm  </li></ul><ul><li>Tolerance  </li></ul><ul><li>Withdrawal  </li></ul>What are features of addiction?
    12. 12. How does Nicotine cause addiction?
    13. 13. Nicotine & the brain <ul><li>Activation of reward centres lead to strong sub-conscious urges to smoke in the presence of ‘cues’ </li></ul><ul><li>Similar mechanism as pleasure from food, sex, caffeine, alcohol (hence weight gain) </li></ul>
    14. 14. 1. Positive reinforcement: pleasure Dopamine release in the mid brain Subsequent repeat puffing makes behaviour more likely Puff on a cigarette gives a rapid nicotine ‘hit’ ‘ Feel good factor’ reinforces behaviour
    15. 15. 2. Negative reinforcement: withdrawal Withdrawal discomfort Puff on a cigarette Withdrawal relief More puffs Repetition of this process leads to deeply entrenched behaviour Nicotine broken down
    16. 16. Withdrawal Signs and symptoms Duration Prevalence Irritability < 4 weeks 50% Depression < 4 weeks 60% Restlessness < 4 weeks 60% Poor concentration <2 weeks 60% Increased appetite >10 weeks 70% Sleep disturbance <1 week 25% Urges to smoke >2 weeks 70% Mouth ulcers >4 weeks 40% Constipation >4 weeks 17%
    17. 17. Intrepid Journeys Nicotine
    18. 18. CAN YOU HELP A SMOKER? <ul><li>Interventions for smoking cessation </li></ul>
    19. 19. Smoking cessation is easy! <ul><li>A is for ask </li></ul><ul><li>B is for brief advice to quit </li></ul><ul><li>C is for cessation support </li></ul>Ministry of Health. 2007 . New Zealand Smoking Cessation Guidelines. Wellington: Ministry of Health.
    20. 20. Brief Advice: Personalise <ul><li>“ To improve your health, the best thing you can do is stop smoking - particularly to improve your [ personal health issue ]. Different options suit individual smokers which have been proven to help, such as [ treatment options ]. Would you like to try one of these? ” </li></ul>
    21. 21. Benefits of quitting <ul><li>Increased life expectancy (8 years) </li></ul><ul><li>Lung cancer risk ↓ by ½ after ten years </li></ul><ul><li>Heart disease risk ↓ to non-smoker level after 10 years </li></ul><ul><li>Lung function decline reduced </li></ul><ul><li>Reproductive health improved </li></ul><ul><li>Post-operative recovery improved </li></ul>Source: RCP Tobacco Advisory Group PowerPoint Files. Available at:
    22. 22. How can I support my smoker? <ul><li>Self-help materials </li></ul><ul><li>Give face-to-face support </li></ul><ul><li>Refer for face-to-face support (AKP) </li></ul><ul><li>Refer for Telephone support </li></ul><ul><li>Pharmacotherapy </li></ul><ul><ul><li>nicotine replacement therapy (patches, gum etc) </li></ul></ul><ul><ul><li>bupropion </li></ul></ul><ul><ul><li>nortriptyline </li></ul></ul><ul><ul><li>varenicline </li></ul></ul>
    23. 23. DOES CESSATION SUPPORT WORK? <ul><li>Behavioural </li></ul><ul><li>Pharmaceutical </li></ul>
    24. 24. Nicotine delivery
    25. 25. Time to first cigarette <ul><li>Smokes w ith in 30 minutes after waking: Higher degree of tobacco dependence </li></ul><ul><ul><li>More NRT (full strenth patch and gum prn) </li></ul></ul><ul><li>Smokers after 30 minutes after waking: Lower degree of tobacco dependence </li></ul><ul><ul><li>Less NRT (medium strength patch & gum prn) </li></ul></ul>
    26. 26. Chew-park-chew
    27. 27. How long to treat? Abstinence vs harm reduction <ul><li>8-12 weeks (abstinence model) </li></ul><ul><li>Required for re-adaptation of smoker’s brain </li></ul><ul><li>As long as required (harm reduction) </li></ul><ul><li>Encourage ‘gum in glove box’ for relapse prevention </li></ul>
    28. 28. Safety and myths <ul><li>Over 30,000 patients used NRT for over 30 years </li></ul><ul><li>Nicotine is responsible for addiction – not cancer </li></ul>
    29. 29. What to tell patients… <ul><li>Not a magic cure, effort still needed </li></ul><ul><li>Provides nicotine, but more slowly and lower dose than cigs </li></ul><ul><li>Takes edge off discomfort </li></ul><ul><li>Oral product can be unpleasant initially, must persevere to benefit </li></ul><ul><li>Need to use for 2-3 months continuously </li></ul><ul><li>Ignore small print in medication inserts </li></ul>
    30. 30. GROUPS <ul><li>Bang for your buck. </li></ul>
    31. 31. Running a group <ul><li>5-10 ideal </li></ul><ul><li>Some skills </li></ul><ul><li>4-6 sessions </li></ul><ul><li>Quiet room </li></ul><ul><li>Quit cards </li></ul><ul><li>Remember: “There is no teaching without learning” </li></ul>
    32. 32. First session <ul><li>Series of questions </li></ul><ul><li>“ Well, most of you sound like you want to give up smoking, but something within you keeps you reaching for cigarettes, why is this?” </li></ul><ul><li>“ Tell us about the times you have stopped smoking for a few hours or days? What happened? Did you feel strange or different to normal?” </li></ul>
    33. 33. First session <ul><li>“ Have any of you tried to cut down and stop in the past? What happened then?” </li></ul><ul><li>“ Tell us about the situations that tend to set off your smoking?” </li></ul><ul><li>“ What things have helped you stop in the past?” </li></ul><ul><li>“ What aspect of cigarettes causes damage to your health – nicotine, tar or both?” </li></ul><ul><li>“ When you smoke a cigarette, how fast do you experience a hit or rush?” </li></ul>
    34. 34. <ul><li>Explain addiction </li></ul><ul><ul><li>-E.g. Monster on your shoulder tells you to smoke </li></ul></ul><ul><ul><ul><li>Cigarettes feed the monster </li></ul></ul></ul><ul><ul><ul><li>Time off smoking kills the monster (not one puff) </li></ul></ul></ul><ul><ul><ul><li>Worst is over in a month </li></ul></ul></ul><ul><li>Ask about cues </li></ul><ul><ul><li>Stress </li></ul></ul><ul><ul><li>Smokers </li></ul></ul><ul><ul><li>Beer, coffee </li></ul></ul>Support? <ul><li>Debunk myths </li></ul><ul><ul><li>Doesn’t cause cancer </li></ul></ul><ul><ul><li>Prolongs addiction </li></ul></ul><ul><ul><li>Cutting down doesn’t cut it! </li></ul></ul><ul><li>Quit day </li></ul><ul><ul><li>Set quit day (work vs w/e, holiday) </li></ul></ul><ul><ul><li>Throw away cigarettes, ashtrays etc </li></ul></ul><ul><ul><li>Enlist friends/family support </li></ul></ul><ul><ul><li>Non smoker identity </li></ul></ul>
    35. 35. Debunk myths <ul><li>If you want to stop you must first cut down </li></ul><ul><li>Nicotine is dangerous </li></ul><ul><li>The best way to quit is cold-turkey - using NRT is like having local anaesthetic when going to the dentist – yes it can be done, but it makes the post quit period alot more bearable. </li></ul>
    36. 36. Sugar and carbs, are they addictive?
    37. 38. Is there an obesity epidemic?
    38. 40. Bread - White vs Vogel’s
    39. 41. Is Obesity an addiction? <ul><li>Anecdote, often limited to severely obese </li></ul><ul><li>“ Atkins Diet” </li></ul><ul><li>An executive who had had obesity surgery, laxatives, etc “often I would shake until I could put some sugar in my mouth” </li></ul><ul><li>“ I had an hour’s drive from my office to my home, and I knew every restaurant, every candy machine and every soft drink dispenser along the whole route.” </li></ul>
    40. 42. “ For the first three weeks I cut all sugar and flour from my diet and suffered mood swings and depression, even a sense of hopelessness, I had horrible stomach pains, all my joints and muscles throbbed, and I had the shakes constantly...horrible headaches went along with all this.... People who knew me started thinking I was hiding a drug problem. The symptoms have been gone for about two weeks now, and the cravings are finally starting to subside… I look at birthday cake today and all I see is myself curled up in the foetal position crying in bed. “
    41. 44. “ Any addictive type of hypothesis can't explain the rise that we've seen over the last 20 to 30 years of obesity. It's not that the whole population becoming more of an addictive personality type or whatever. I think there are other factors to explain obesity at a population level.” “I think the processes within the brain, of how the brain handles drugs like nicotine and how the brain handles nutrients like glucose are very different indeed.” Boyd Swinburn, Professor of Population Health, Deakin University 13 Jan 2009
    42. 45. Summary <ul><li>Addiction – loss of control </li></ul><ul><li>Withdrawal and tolerance key </li></ul><ul><li>Time to reward crucial (NRT) </li></ul><ul><li>Behavioural and pharmacological treatment </li></ul><ul><li>Abstinence vs harm reduction </li></ul><ul><li>Food consumption shows lack of control similar to other addictions </li></ul><ul><li>Still controversial </li></ul>