Addiction

• What is addiction?

  > a disorder in which an individual takes a substance or engages in a behaviour that is pleasurable but eventually becomes compulsive with harmful consequences

  > marked by physiological and/or psychological dependence, tolerance and withdrawal
• What is physical dependence?

  A state of the body due to habitual substance abuse which results in a withdrawal syndrome when use of the drug is reduced or stopped
• What is psychological dependence?

  A compulsion to continue taking a substance (or continue performing a behaviour) because its use is rewarding
• What is tolerance?

  > A reduction is response to substance, so that an addicted individual needs more to get the same effect

  > need greater dosage to get same effect

  > caused by repeated exposure to the effects of a substance
• What is withdrawal syndrome?

  A set of symptoms that develop when an addicted person abstains from or reduces their substance abuse
• What are risk factors?

  Any internal or external factors that increases the likelihood a person will start using addictive substances or engage in addictive behaviours
• Physical and psychological dependence

  > physical dependence defined in terms of withdrawal -> only possible to establish for certain that someone is physically dependent on a substance when they abstain from it -> said to have occurred when a withdrawal syndrome is produced by reducing or stopping intake

  > psychological dependence refers to compulsion to experience the effects of substance (increase in pleasure or lessoning of discomfort) is followed by a reward -> person will keep on taking substance until becomes habit, despite harmful consequences
• What is behavioural tolerance?

  > happens when an individual learns through experience to adjust their behaviour to compensate for the effects ofa substance

  > e.g. people addicted to alcohol learn to walk more slowly when they are drunk to avoid falling over
• What is cross-tolerance?

  > developing tolerance to one type of substance (e.g. alcohol) can reduce sensitivity to another type (e.g. benzodiazepines)

  > classic issue in surgery -> people who have developed tolerance to the sleep-inducing effects of alcohol need higher doses of anesthetic

  > cross-tolerance can be used therapeutically by giving benzodiazepines to people withdrawing from alcohol to reduce the withdrawal syndrome
• Withdrawal syndrome symptoms

  > almost always tend to be opposite of the ones created by substance

  > e.g. smoker may find smoking relaxes them, but withdrawal from nicotine produced anxiety, irritability and agitation
• withdrawal syndrome - physical and psychological dependence

  > existence of withdrawal indicated that physical dependence has developed

  > once dependence develops, an addicted person experiences some symptoms of withdrawal whenever they can't get the substance

  > happens often, so they become familiar with these symptoms , which are unpleasant and cause discomfort

  > the motivation for continuing to take substance is partly to avoid the withdrawal symptoms -> secondary form of psychological dependence
• What are the two phases of withdrawal?

  > acute withdrawal phase begins within hours of abstaining and features intensive cravings for the substance, reflecting strong physiological and psychological dependence. The symptoms gradually diminish, usually over days

  > the prolonged withdrawal phase includes symptoms that continue for for weeks, months and even years. The person becomes highly sensitive tp the cues they associate with the substance (e.g. lighters) -> one reason why relapse is so common
• What are risk factors?

  Any internal or external influence that increases the likelihood a person will start using addictive substances or engage in addictive behaviours
• What is genetic vulnerability?

  Any inherited predisposition that increases the risk of a disorder or condition
• What is stress?

  Stressful life events and traumatic experiences in childhood and adulthood are important risk factors for addiction
• What is personality?

  Various traits can increase an individuals risk of addiction, a significant one being impulsivity
• What are family influences?

  How much the at-risk individual believes his or her parents approve of addictive substances or behaviours is an influential risk factor, along with others involving family
• How are peers involved with risk factors?

  How attitudes of peers towards addictive substances/behaviours becomes highly influential in increasing the risk of an addiction developing in adolescence
• Risk factors - genetic vulnerability

  > D2 receptor = dopamine transmission affected by number of dopamine receptors you have - genetically controlled. People addicted found to have abnormally low number of D2 receptors -> fewer receptors means less DA activity - using drugs is way of compensating this deficiency

  > Nicotine enzyme = some more able to metabolise certain substances. Pianezza (1998) found some people lack fully functioning enzyme which metabolises nicotine -> smoke significantly less than those with fully functioning gene. Expression of this gene is genetically determined.
• Risk factors - stress

  > Anderson and Teicher (2008) highlighted role of adverse childhood experiences in later addiction

  > they argue that early experiences of severe stress have damaging effects on a young brain in a sensitive period of development -> creates vulnerability to later stress

  > Further stressful experiences in adolescence and adulthood trigger the early vulnerability and make it more likely that such a person will self-medicate with drugs or other behavioural addictions
• Risk factors - personality

  > no such thing as generally addictive but addiction is linked to disordered personality

  > most people with antisocial personality disorder (APD) are also addicted substance abusers

  > Robson (1998) argued that APD is a casual risk factor for addiction because having APD means that a person breaks social norms, is impulsive and may behave criminally

  > therefore -> almost inevitable that someone with APD will try drugs at young age as drug-taking offers a combination of norm-breaking, criminal activity and also satisfying own desires
• Risk factors - Family influences

  > Livingston (2010) found that final-year high-school students who were allows to their parents to drink alcohol at home were significantly more likely to drink excessively, the following year at college

  > Adolescents who believed tat their parents had little or no interest in monitoring their behaviour (e.g. internet use, peer relationships) are more likely to develop an addiction

  > key determinant = adolescent's perception -> more important than whether or not parents really monitor the adolescent's behaviour
• Risk factors - peers

  O'Connell (2009) suggests there are three major elements to peer influence as risk factors

  > An at-risk adolescent's attitudes and norms about drinking are influenced by associating with peers who use alcohol

  > These experienced peers provide more opportunities for the at-risk individual to use alcohol

  > The individual overestimates how much their peers are drinking -> drink more to keep up with perceived norm

  Peer influence doesn't have to specifically concern the substances -> the creation of the group norm that favours rule-breaking generally is what matters
• Strength of genetic vulnerability as a risk factor

  (+) support from adoption studies

  > Kendler (2012) used data from National Swedish Adoption Study

  > looked especially at adults who had been adopted away, as children, from biological families in which at least one parent had an addiction, compared with adopted-away individuals with no addicted parent in their biological families

  > This supports the role of genetic vulnerability as important risk factor -> supported by other research (e.g. twin studies)
• Limitation of stress as a risk factor


  (-) issue of causation

  > many studies show strong positive correlation between stress & addiction

  > But this doesn't necessarily mean stress is the risk factor

  > what matters = order in which stress & addiction developed

  > some may become addicted without any significant life stress

  > their addiction then creates greater level of stress (negative effects of lifestyle) -> still produce a pos correlation, but in this case addiction caused the stress

  > Therefore: can't conclude stress is significant risk factor based on correlational studies alone
• Strength of personality as a risk factor

  (+) support for link between addiction and APD

  > Several studies show that APD and alcohol dependence are co-morbid (frequently occur together)

  > Bahlmann (2002) interviewed 55 alcohol-dependent people of which 18 also diagnosed with APD -> for these 18, the researcher found that APD developed four years before their alcohol dependency on average

  > this finding suggests that APD is a personality-related risk factor for alcohol addiction
• Strength of family influences as a risk factor

  (+) research support

  > Madras (2019) found a strong positive correlation between parents use (abuse) of cannabis and their adolescent children's use of cannabis, nicotine, alcohol and opioids

  > may be that they observe their parents using a specific drug (e.g. cannabis) and model this behaviour (SLT)

  > may also infer their parents approve of drug use generally, so go on to use other drugs

  > this supports view that parental substance abuse is a potential risk factor for wider addiction in adolescent offspring
• Strength of peers as risk factor

  (+) real-world application

  > Social norms marketing advertising (SNMA) = intervention to change mistaken beliefs about how much peers are drinking -> uses mass media advertising to provide messages & statistics about how much people really drink

  > example = beer mats, posters and leaflets in a student union bar might carry a message such as ' Students overestimate what others drink by 44%' -> students may get more accurate picture to correct their overestimation

  > means: identification of risk factors can suggest ways to reduce the influence of such factors
• Strength of looking at risk factors together

  (+) point to the overriding interaction with genes

  > Most risk factors proximate (act as immediate influence)

  > e.g. high stress levels directly increase risk as does personality trait of novelty-seeking (craving new experiences)

  > But how we respond to stress and extent to which we seek novelty are both partly genetic

  > so to fully understand risk factors - look further back in chain of influences to ultimate risk factors -> many cases = genetic

  > So, genetic vulnerability may be most sig risk factor as has ultimate influence on others
• Limitation of focusing on individual risk factors

  (-) ignore the effects of interactions & may ignore the positive effects

  > Mayes & Suchman (2006) point out that different combinations partly determine nature & severity of an addiction

  > Also, the factors described as 'risky' can be protective - personality traits, genetic characteristics, family & peer influences can reduce risk (e.g. greater parental monitoring & lower levels of impulsivity)

  > So, a more realistic view = think in terms of multiple 'pathways' -> include different combinations interacting and some having a positive effect
• What is neurochemistry?

  Relating to chemical in the brain that regulate biological and psychological functioning
• What is dopamine?

  > A neurotransmitter that generally has an excitatory effect and is associated with the sensation of pleasure

  > Usually high levels are associated with schizophrenia and usually low levels are associated with Parkinson'd disease
• How is neurochemistry involved in nicotine addiction?

  > involves neurotransmitter dopamine

  > Dani & Heinemann (1996) focused on dopamine in their desensitisation hypothesis of nicotine addiction
• Neurochemistry of nicotine addiction - nAChRs & dopamine


  > Neurotransmitter acetycholine (ACh) plays key role in nervous system activity -> means there's ACh receptors on surface of neurons in CNS

  > one subtype of ACh receptor = nicotonic acetylcholine receptor (nAChR) -> activated by ACh or nicotine

  > when activated by nicotine - neuron transmits DA -> immediately followed by shutdown - nAChRs shut down and temporarily can't respond to any neurotransmitters

  > neuron is said to be desensitised -> leads to downregulation - reduction in number of active neurons as fewer of them are available
• Neurochemistry of nicotine addiction - creating a pleasurable effect

  > nAChRs concentrated in ventral tegmental area (VTA) of brain -> when stimulated with nicotine, DA transmitted along mesolimbic pathway to nucleus accumbens (NA)

  > triggers release of more DA from NA into frontal cortex

  > DA also transported along mesocortical pathway to be released directly in frontal cortex

  > mesolimbic & mesocortical pathways part of brain's DA reward system -> nicotine activates this system & results in pleasurable effects

  > these become associated with smoking through operant conditioning
• Neurochemistry of nicotine addiction - Withdrawal

  > as long as person's smoking, nAChRs are continually desensitised

  > when person doesn't smoke for prolonged period of time, nicotine disappears from their body

  > the nAChRs become functional again, so DA neuron resentise and more become available (upregulation)

  > person experiences symptoms of withdrawal at this time from lack of nicotine
• Withdrawal describes in terms of nAChRs

  > During resensitisation nAChRs become overstimulated by ACh (as no nicotine to bind with them) -> nACHRs at most sensitive at this point

  > Often why smokers describe first cigarette of day as most enjoyable -> strongly reactivates the DA reward system
• Neurochemistry of nicotine addiction - Dependence and tolerance

  > smoker avoids unpleasant physiological & psychological withdrawal states by having another cigarette

  > means there's a constant cycle of daytime downregulation & night-time upregulation -> creates long-term desensitisation of nAChRS

  > continuous exposure to nAChRS to nicotine causes permanent changes to brain neurochemistry - decrease in number of active receptors

  > tolerance develops as a smoker has to smoke more to get same effects
• Evaluation of neurochemistry of nicotine addiction - Research support

  (+) support from human research

  > research has provided indirect support for role of DA

  > McEvoy (1995) studied smoking behaviour in people with sz who were taking antipsychotic drug which acts as DA antagonist (blocks DA receptors in brain)

  > People taking the drug showed a significant increase in smoking -> presumable a form of self-medication -> individuals used nicotine as means of increasing their depleted DA levels

  > this supports view that DA has a key role in neurochemistry of nicotine addiction
• Evaluation of neurochemistry of nicotine addiction - role of DA is limited

  (-) consider only the role of DA are limited

  > The DA system is central but research increasingly shows a complex interaction of several neurochemical systems

  > According to Watkins (2000) these neurotransmitter pathways (e.g. serotonin), plus other systems such as endogenous opioids (endorphins - brains natural painkillers)

  > Therefore, the neurochemistry of nicotine addiction can't be fully understood if looking at only dopamine