2 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.
3 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 functionSome drugs are known as dopamine agonists.These drugs bind to dopamine receptors in place of dopamine &directly stimulate those receptors.
4 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.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.Thinking point: At this point think about the role of dopamine inrelation to addiction e.g. what about gambling/gaming...couldyou describe how dopamine can be used as a viable theory toexplain these addictions?
5 The disease model-Genetics There is no single addiction Gene.Scientists will never find just one single addiction gene.Susceptibility to addiction is the result of many interacting genes
6 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 genesUsing pedigree data, researchers can begin to hunt down genes.They begin by comparing DNA sequences of individuals who have the diseasewith those who do not. They can then narrow down the possibilities to identify asmall number of so-called "candidate genes" for addiction.Source:http://learn.genetics.utah.edu/content/addiction/genetics/
7 Glen Hanson cont…There are many ways that genes could cause one person to be more vulnerable to addiction than another.Starting addictive behaviour.Continuing with additive behaviour.Activating the reward system.Feelings of pleasure.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 genesLike other behavioural diseases, addiction vulnerability is a very complex trait. Many factors determine the likelihood that someone will become an addict
8 The story of John & James. John Crawford has an identical twin. His 16-year-old 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 formingall the cells in the body and directing their activity.
9 Can addiction run in families Can addiction run in families? Let us assume John & James have a parent who struggles with alcoholismQ: 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.GeneticsAge,Presence of other diseases,DietStress,Peer pressure.
10 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.
11 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??
12 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? .Or is there a sex-linked genetic mechanism at play that is contributing to this phenomenon?How much of this phenomenon has its basis in genetics.
13 3. Comings et al (1996) also found similar Further evidence…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 similarfindings in the investigation looking into behavioural addictions such as gambling
14 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…..
15 You have 10 mins to complete this task. 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?Why are twin studies a good method for examining the role of genetics in addictive behaviour.Usual rules apply!You have 10 mins to complete this task.
16 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.
17 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!!
18 Things that make you go hmmm!!! Pleasure is an important factor in healthy development. Would you eat McDonalds/Chocolate again if it were not pleasurable?These feelings act as reinforcers...therefore pleasure encourages essential behaviours or in some cases unhealthy behaviours......we all have our crosses to bear..Is addiction is the price we pay??
19 Evaluation of biological explanations. FoesNeurotransmitters 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.FriendsBiological 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 otherevaluative points too!Method, Ethics, AID,Keywords etc.
20 Cognitive explanations of addictive behaviour. Faulty ThinkingIrrational biasesExample= Gambling“I will win, I can control the odds, if I use my lucky numbers I'll be rich one day.”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.
21 Evaluation of cognitive explanation FoesFriendsSkill perception varies across individuals Cannot establish cause & effect because skill is not consistent among gamblers or irrational.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.Helps explain individual differences During development of maintenance stage faulty biases may be more likely to develop problems.
22 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!!
23 In review.... Components of addiction....Check Models of addiction....CheckBiological/Cognitive.....CheckA little of behavioural too....a little check!Evaluation of two models...Check
24 Try these questions to check your understanding so far 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
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