Flashcards in Week 12 Chapter 10 Substance Use Disorders Aetiology of Substance Use (Caff) Deck (27)
What is the process by which people become physiologically dependent on a substance?
They begin with a:
*positive attitude toward a substance,
*then begin experimentation
*move to regular use
*this turns to heavy use
*then become dependent on the substance
Why does it appear that the factors that contribute to substance use disorders may depend on the point in the process that is being considered?
Developing a positive attitude toward smoking & beginning to experiment with tobacco are strongly related to smoking by other family members
*In contrast, becoming a regular smoker is more strongly related to smoking by peers & being able to acquire cigarettes readily
What does a developmental approach to substance use problems among adolescents tell us about the different trajectories young people can take toward substance abuse?
Substance use problems among adolescents take different trajectories, for example a group may begin drinking early on and develop greater usage, whereas another group may drink a smaller quantity and then peak later with heavy drinking
When considering the development of substance use problems among adolescents what does our knowledge of the developing brain tell us?
*The Frontal Cortex is still developing and is linked to judgement & Decision making, novelty seeking and impulse control
*The neural systems believed to be important for reward, including dopaminergic, serotonergic, & glutamatergic pathways all pass through the still developing frontal cortex
Why does the developmental approach not suffice as an explanation for all cases of substance abuse or dependence?
*A developmental approach fails to account for all cases:
e.g. heavy tobacco or heroin use does not always lead to dependence
*It is not inevitable for a person to pass through all stages of dependence
e.g. some people have periods of heavy use, then return to moderate use
*Still others do not require a heavy period of use to become dependent
What has research - particularly twin studies - shown us about children of relatives with substance use disorders?
That there is a great concordance in identical twins than in fraternal twins for alcohol use disorder, smoking, heavy use of marijuana, and drug use disorders in general
What have behavioural genetic studies shown us about illicit drug use disorders?
Genetic and shared environmental risk factors appear to be the same no matter what the drug. This is true for both men and women
Research has uncovered some gene-environment interactions in alcohol and drug use. What have they found?
Peers & parents appear to be particularly important:
*heritability for alcohol problems is higher among adolescents with large No.s of peers who drank
*similarly for smoking best friend who drinks and smokes
*heritability for smoking was greater for teens who went to school where the popular crowd smoked compared to when the popular crowd did not smoke.
*heritability was higher for teens with parents who were low monitors of their behaviour
What evidence is there to support the theory that the ability to tolerate large quantities of alcohol may be inherited?
Some ethnic groups (Asians) have low rate of alcohol problems due to a physiological intolerance caused by an inherited deficiency in enzymes involved in alcohol metabolism, called alcohol dehydrogenases or ADH. (genes affected are ADH2, ADH3)
*About 3/4 of Asians experience unpleasantness from small amounts of alcohol which may protect them from becoming dependent
What is the evidence to support the notion of genetic factors involved in nicotine addiction?
Like most drugs, nicotine appears to stimulate dopamine release & inhibit it's reuptake - people more sensitive to these effects of nicotine are more likely to become regular smokers
*Gene that regulates dopamine reuptake is SLC6A3
*One form of SLC6A3 has been linked to a lower likelihood of smoking & a greater likelihood of quitting
*genes such as CYP2A6 contribute to the body's ability to metabolise nicotine - those with a slower nicotine metabolism are more likely to become dependent whilst those with reduced activity on CYP2A6 smoke fewer cigarettes & are less likely to become dependent
Why is it not surprising that dopamine is featured in all discussions about substance use?
*People take drugs to feel good & to feel less bad
*Dopamine pathways in the brain are importantly linked to pleasure and reward
*The mesolimbic pathway is particularly stimulated by drugs
*People dependent on drugs or alcohol are thought to have a deficiency in the dopamine receptor DRD2
What are the two models put forward to explain drug interaction in the dopamine system?
*The vulnerability model
Suggests that problems within the dopamine system increase the vulnerability to become drug dependent alternatively
*The Toxic effects model
Suggests that problems in the dopamine system are the consequence of taking substances
For cocaine use there is evidence to support both theories
Why is relapse so common in drug-taking behaviour?
Once a person becomes dependent on a substance people continue to take drugs to avoid the bad feelings associated with withdrawal. This is particularly the case for drugs whose withdrawal symptoms are excruciatingly unpleasant (such as alcohol, methamphetamine, heroin)
Tell me about the neurobiological theory, referred to as the 'incentive-sensitisation theory' of substance use that considers both the craving (wanting) & the pleasure (liking).
The dopamine system linked to pleasure becomes super-sensitive to both the cues associated with taking the drug (needle, spoon, rolling paper) & the direct effects of the drug.
This sensitivity to cues induces craving (wanting) & people go to extreme lengths to seek & obtain drugs.
Over time the like of drugs decreases, but the wanting remains very intense
It is the transition from liking to powerful wanting maintains the addiction
What evidence is there to support the neurobiological theory of substance use?
*Those who were dependent on cocaine showed changes in physiological arousal, increases in craving, & 'high' feelings, & increases in negative emotions in response to cues of cocaine which consisted of audio & videotape of people preparing to inject or snort cocaine, compared to those not dependent.
*Brain imaging studies have shown that cues for a drug (needle/cigarette) activate the reward & pleasure areas of the brain implicated in drug use
Do people who crave a substance more actually use it more (even when they are trying to quit?
Yes, this has been found to be the case in both cigarette and alcohol studies
*Heavy drinkers who reported greater 'wanting' & 'liking' of alcohol were drinking more at 2 year follow up than heavy drinkers who reported less 'wanting' & 'liking' of alcohol
Drugs are used to enhance positive moods or to diminish negative moods. Drugs can also be used to relieve boredom.
What psychological factors can contribute to different experiences of mood alteration?
*Drugs are often used to reduce tension
eg Stress might lead to increases in smoking
- however, this is dependent on both the circumstance and the drug user
-whether someone is a new smoker or a life long smoker makes a difference
-there is evidence to suggest the act of inhaling (rather than the tobacco itself) actually decreases stress
*Distraction can reduce cravings also
Alcohol does not actually relieve stress after the stressful event has passed, so why do so many people drink with the aim of relieving tension?
People expect it to reduce tension.
*Our expectancies play a role in how we experience drugs
*There is a perpetuating cycle where the expectation that drinking will reduce anxiety increases drinking, which in turn makes the positive expectancies even stronger
What other expectancies influence our drug taking behaviour?
*the belief that a drug will stimulate aggression & increase sexual responsiveness predicts increased drug use
*people who falsely believe that alcohol will make them seen more socially skilled are likely to drink more than those who accurately predict it can interfere with social interactions
How does perceived risk influence our drug taking behaviour?
*positive expectancies predict alcohol use and alcohol use helps to maintain & strength positive expectancies
*In general, the greater the perceived risk of a drug, the less likely it will be used.
Which personality factors been shown to influence our drug taking behaviours?
*High levels of negative affect (or negative emotionality)
*a persistent desire for arousal,
*increased positive affect
*constraint (cautious behaviour)
*conservative moral standards
Which personality factors been shown to indicate likely drug taking behaviours?
Low constraint & High negative affect
have predicted onset for alcohol, nicotine, and illicit drug use in both men and women
Anxiety & novelty seeking have predicted the onset of getting drunk, using drugs & smoking
Depression has not been found as a factor in starting smoking
How have sociocultural factors been shown to influence our drug taking behaviours?
People's interest in and access to drugs are influenced by peers, parents, the media, and cultural norms about acceptable behaviour
What are some of the findings from a cross-national study of high school students as to commonalities in substance use across 36 countries?
*Alcohol is the most commonly used substance
*Marijuana was next most commonly used
*Where marijuana use was frequent there were also high rates of amphetamines, ecstasy and cocaine use
What are some of the sociocultural findings regarding substance use
*Cultural attitudes & patterns of drinking influence the likelihood of drinking alcohol
*In most cultures men drink more than women though the cultural norms about drinking influence the amount
*availability of the substance makes a huge difference to rates of abuse: liquor store owners, bartenders have higher rates of alcohol use
*exposure to alcohol use by parents increases children's likelihood of drinking
*a lack of parental monitoring leads to increased drug-abuse
How does the social setting influence a person's substance use?
There is the social influence model:
*Smokers are more likely to smoke with other smokers
*Having friends who smoke predicts smoking
*Peer influencing are important for alcohol and marijuana smoking
& the Social Selection Model:
*People who are inclined to develop substance use disorders may actually select social networks that conform to their own drinking or drug use patterns
*Research supports both models