Week 11 - Substance Use and Addictive Disorders Flashcards
Substance Use Summary
- People have always used drugs
- A small percentage of these become addicted
- Three factors to whether someone become addicted
Drug related factors
Social factors
Personal Biologial factors (like individual sensitivity differences)
(Most people can use drugs without it becoming and issue)
How do you Define Addiction
- The term addict originated as a verb and meant to ‘devote or surrender’
(you would devote or addict yourself to something) - It has come to be a noun mean ‘a person who is addicted to a particular substance’
- How do you characterise the progression from normal drug use to addiction?
Are there universal characteristics of an addict?
(looking at it from disorder standpoint)
Psychiatric Definition
Diagnostic and statistical manual of mental disorder (DSM)
Does not use the term ‘addiction’
Previous editions set forth specific criteria for substance dependence and substance abuse
Current edition (DSM-5) combines substance dependence and abuse into “Substance Abuse Disorder” which can vary from ‘mild’ to ‘severe’
DSM-5 Criteria for substance abuse disorders
- Taking the substance in larger amounts or for longer than you meant to
- Wanting to cut down or stop using the substance but not managing to
- Spending a lot of time getting, using, or recovering from use of the substance
- Cravings and urges to use the substance
- Not managing to do what you should at work, home, or school because of substance use
- Continuing to use, even when it causes problems in relationships
- Giving up important social, occupational, or recreational activities because of substance use
- Using substances again and again, even when it puts you in danger
- Continuing to use, even when you know you have a physical or psychological problem that could have been caused or made worse by the substance
- Needing more of the substance to get the effect you want (tolerance)
- Development of withdrawal symptoms, which can be relieved by taking more of the substance
How to determine the severity of substance abuse disorder
- Clinicians can specify the severity depending on the number of symptoms present
- Two or three – mild
- Four or five – moderate * Six or more – severe
- Many other criteria for substance use and abuse are similar to these (e.g., ICD – 10 an alternative to the DSM)
- They usually state that:
- The addicted individual has impaired control over the use of the drug
- The drug use has harmful consequences
Problems with these types of criteria?
- They rely on knowing whether an individual is “in control” or not
- How do you know this just by observing behaviour?
- Cannot rely on self-report either
People in self-report will probably say they’re in control of their drug use, but that is in partly because they don’t know how out of control they are and partly because of conditioning to ‘be in control’ - By focusing on harm, we can avoid this pitfall by assuming
- Any behaviour that is harmful is “out of control”
- Reduce diagnosis to whether the use is harmful to individual or others on the assumption that people probably don’t do things to harm others
Other associated concepts to substance abuse; Craving
-Craving (when you are addicted)
Suffers from the same problem as ‘control’ - it hard to specify what this looks like in people and create objective measures for it.
- Dependence and addiction
Used to be used interchangeable, but not anymore (as you can be dependant but not addicted) - Addiction is a chronic and relapsing disorder
Can never be ‘cured’ can only be in remission
Symptoms could reappear at any time
(We can’t fix it but we can manage it)
History of Drug use and Addiction
- Until the mid-19th century drug addiction was considered to result from deficiencies in character, moral fibre, willpower, or self control. (it’s a ‘you problem’)
- Addiction was a problem for priests and clerics to understand (who dealt with morality)
- The effects of addiction were dealt with by the legal system
- There was no scientific study of addiction as it wasn’t a scientific issue but a moral one
Social reform movements of the late 1800s
American Association for the Cure of Inebriates
* Established in 1870 by Joseph Parrish
* First principle was “inebriety is a disease” (rhetoric seen now in AA)
* Encouraged society to offer treatment, rather than punishment to inebriates
Morphine and opium abuse
- By the late 1800s, the US was in an opium and morphine epidemic
- Because these drugs were sold as medicines, abuse of them was
considered to be a medical problem - This furthered the idea of drug abuse as a disease
- Toward the end of the 19th century, temperance and anti-opium movements began using the word “addiction”
- Also adapted by the medical profession
- Began to be used as a way to talk about, diagnose, and explain drug abuse
Modern behavioural explanations of drug abuse
- the medical disease People start using drugs in a recreational manner * Only some people continue on to problematic use
- Why?
- Both disease and dependence models apply to casual use by pointing out something in the brain
- But why do people begin to use drugs casually?
- No innate drive, as with food/sex or to use drugs
What made early research on drug use in animals hard
- Addictive behaviour was considered uniquely human
— laboratory animals would not self administer drugs like humans do. Also argued ‘moral’ deficiency that drives drug-use was human specific
—– conditioned tast aversion (drugs were initially dissolved into a funny tasting solutions that rats wouldn’t drink likely due to the tase of the solution)
—– oral administration (is hard to achieve in animals)
This type of research was used to suggest that animals don’t get addicted
Animals could be made to be physically dependant on drugs but they did not do so voluntarily
therefore, A.R Lindesmith said “Certainly from the point of view of social science it would be ridiculous to include animals and humans together in the concept of addiction”
Concepts drawn from early drug research on animals
- Humans have ‘free will’ and only humans can ‘choose’ to sin by taking drugs
- Animals are unable to associate the relief of withdrawal symptoms to drug administration (as there is too long of a delay between drug administration and effects (15-20 mins)
- Using animals to study addictive behaviour of humans was viewed as a waste of time
Intravenous drug self-administration as a revolution in the study of drugs
- in the 1950’s researchers developed a way to allow animals to self-administer drugs intravenously which overcame oral issues and better matched the human condition
- thousands of studies have been conducted on animals self-administering drugs
- humans self-administration studies have also been conducted
Similarities and difference between humans and non-human animals when it comes to drug use
Type of drugs
- lab animals will take almost all of the drugs that humans use
some drugs appear to have aversive qualities or properties
- and animals will respond to avoid administration of them
eg. LSD, some anti-psychotics and antidepressants
Pushes lever to stop LSD intake. This means they can discriminate between being on the drug or not and deciding if they want it or not
Pattners of self administration in humans and rhesus monkey as a model for self-administration in animals
Similar patterns between humans and lab animals
(good photo in slides)
Conclusions on self-administration studies
- Initially assumed that physical dependence was necessary for self- administration
- Researchers would establish physical dependence before giving animals the opportunity to self-administer
- Soon became clear that physical dependence was not necessary
- Animals would self-administer drugs and doses of drugs that did not cause physical dependence
Drugs as positive reinforcers
- Positive reinforcer – any stimulus that increases the frequency of a behaviour it is contingent upon
- Do drugs satisfy this definition?
- By mid to later 1990’s had good body of evidence on positive reinforcement so we as researchers wanted to know whether this body of literature could be applied to a drug-confidence
Pickens and Thompson 1968 - self-administering cocaine
Implanted rats with catheters and gave them the opportunity to self-administer cocaine
- the character of drug self-administration fit the criteria for ‘positive reinformcent’
- First 1/2 of the session rats would respond for doing in 2nd 1/2 with no drug, they’d give no response. This was the same response with food.
(response shart in slides)
How will animals self-administer drugs?
- Much research has now shown that animals will self-administer drugs in a variety of ways
- Intragastric
- Intracranial
- Intraventricular * Inhalation
- Orally
- Self-administration is the gold standard by which we have learned most of what we know about drug use
Problems with positive reinforcement model (list)
Positive reinforcement paradox
Positive reinforcement paradox: = why keep doing something that causes negative consequences?
Positive reinforcement paradox explained
Positive reinforcement paradox: why keep doing something that causes negative consequences?
The positive consequences of a drug are immediate
- negative consequences are delayed, often by a long
Temporal discounting…
- this refers to how the positives outweigh the negatives because you get positives now and deal with the negative later.
- unsure if this steep discounting curve is by individual differences or the drug itself
Circularity of positive reinforcement
- Definition of positive reinforcement is circular - to know if something is a positive reinforcer, you have to test it and see if behaviour increases which is hard to test
- Decades of research have told us about positive reinforcement
We know what to expect in terms of effects on behaviour
We can test aspects of drugs with other positive reinforcers - Neuroscience has begun to delinieate the neural mechanisms of positive reinforcement – getting closer to firming up the circularity of positive reinforcement
Factors that alter the reinforcing value of drugs
Different drugs
- some drugs have more ‘abuse liability’ than others
eg. psychedelics have decreased abuse potential
Dose of a drug
- higher doses are generally more reinforcing than lower doses but too much is bad
Breeding and strain differences
- some strains of lab animals are much more prone to self-administer drugs
Relief of unpleasant symptoms
- self-medication? Tricky to get objective data on
Although this idea has intuitive appeal, little research supports it
Task demand
- the reinforcing value of a particular drug depends on what type of task follows drug administration
People choose amphetamine or caffeine if they need to be vigilant
Choose an analgesis if they are about to undergo a painful procedure
Depending on the task and circumstance the reinforcement property of drugs will be influenced
Stress
- stress increases the rate at which lab animals self-administer drugs.
- stress sensitizes brain reward mechanisms to respond to drugs
Deprivation
- food deprived animals will self-administer drugs
- may be related to stress mechanism
Previous experience with other drugs
- some drugs that are not reliably chosen over placebo will be preferred in individuals with a history of drug use
- Diazepam is preferred by alcohol users
Previous experience with the same drug
- can sensitize neural circuitry to the subsequent effects of drugs
Withdrawal symptoms
- the presence of withdrawal symptoms can reliably increase drug self-administration
Priming or reinstatement
- animals will resume responding for drug after a long period without drug
— non-contingent drug administration, drug associated cues
— considered a model of human drug relapse
Factors that alter the reinforcing value of drugs ; Different Drugs
Different drugs
- some drugs have more ‘abuse liability’ than others
eg. psychedelics have decreased abuse potential
Factors that alter the reinfocing value of drugs; Dose of Drug
Dose of a drug
- higher doses are generally more reinforcing than lower doses but too much is bad
Factors that alter the reinforcing value of drugs; Breeding and Strian Differences
Breeding and strain differences
- some strains of lab animals are much more prone to self-administer drugs
Factors that alter the reinforcing value of drugs; Relief of unpleasant symptoms
- self-medication…
Relief of unpleasant symptoms
- self-medication? Tricky to get objective data on
Although this idea has intuitive appeal, little research supports it
Factors that alter the reinforcing value of drugs; Task Demand
Task demand
- the reinforcing value of a particular drug depends on what type of task follows drug administration
People choose amphetamine or caffeine if they need to be vigilant
Choose an analgesis if they are about to undergo a painful procedure
Depending on the task and circumstance the reinforcement property of drugs will be influenced
Factor that alter the reinforcing value of drugs; Stress
Stress
- stress increases the rate at which lab animals self-administer drugs.
- stress sensitizes brain reward mechanisms to respond to drugs
Factors that alter the reinfocring value of drugs; deprivation
Deprivation
- food deprived animals will self-administer drugs
- may be related to stress mechanism
Factors that alter the reinforcing value of drugs; previous experience with other drugs
Previous experience with other drugs
- some drugs that are not reliably chosen over placebo will be preferred in individuals with a history of drug use
- Diazepam is preferred by alcohol users
Factors that alter the reinforcing value of drugs; previous experience with the same drug
Previous experience with the same drug
- can sensitize neural circuitry to the subsequent effects of drugs
Factors that alter the reinforcing value of drugs; withdrawal
Withdrawal symptoms
- the presence of withdrawal symptoms can reliably increase drug self-administration
Factors that alter the reinforcing value of drugs; Priming or reinstatement
- animals will resume responding for drug after a long period without drug
— non-contingent drug administration, drug associated cues
— considered a model of human drug relapse
Carl Hart Video
- Carl Hart ; Looks at myths about drugs as a professor at Colombia who uses drugs & promotes drug-use as a human right
- ## ‘high price’ book –> data shows many people use drugs but don’t get addicted
Circularity of Reinforcers
- how we know if something is a reinforcer?
well it’s increases rate of behaviour - what types of tings increase rate of behaviour?
Reinforcers
The neuroanatomy of motivation and reinforcement
Motivation system have two components to be useful
- 1. must be able to activate behaviour, allow something to behave
- 2. must be able to direct behaviour; to a given stimuli
Specific biological relevant targets seem to attract us
(eg. food and sex)
The attraction is called incentive (incentive to behave towards certain things)
Olds & Milner (1954) - seminal paper on incentive and pleasure
- electrodes were implanted in the nucleus accumbens in the brain of people chronically depressed
- animals where then able to self stimulate by pressing button to stimulate the nucleus accumbens
- found out rewarding effects of drug occurs in nucleus accumb ens - part of the circuitry
How does the brain respond to morphine
Mophine shuts down the cortex
How does the brain respond to cocaine
Increases all brain areas but in particular regions of the primal brain
The role of dopamine (two theories)
- dopamine as a teacher
- incentive salience
- the pleasure chemical
Dopamine as a teacher
- Wolfman Sholtz ; had monkey in chair with electrical recording from dopamine cells
Got monkey to do task for juice reward
Found that at baseline there is tonic firing, but firing increased when reward was given (unconditioned response)
Then began to learn to get a dopamine hit from the conditioned stimulus (as this predicted. the juice reward)
The conditioning remained even when reward wasn’t given. However, there was a drop at the point when no reward was given when it was expected
Dopamine signals a prediction error (tells you when the environment changes and you need to learn type thing)
So, according to this theory dopamine neurons respond to the earliest predictor of reward, even moreso than when the reward is presented
Problems with the Dopamine as a teacher model
Dopamine is not required for learning
- mice that are genetically engineered to lack dopamine are able to learn stimulus-reward associations
- mice that have higher dopamine activity do not learn faster than control mice
Which suggests that dopa isn’t critical for learning
Incentive Salience Model of Dopamine
There are two separable components of reinforcement
1. the liking; aka the hedonic reaction tot eh receipt of reward
(aka enjoying food when you eat it, pleasure, it’s the euphoric feeling of things)
- the wanting ; the motivational drive that energizes behaviour and directs it towards specific stimuli or events
(eg. craving food if you’re hungry)
How do you separate wanting from liking ?
- ask the animal if they like something, so how do you separate liking vs wanting.
- Hedonic reactions all tend to be similar, as do aversive reactions - like facial reactions
They have also found different areas of the nucleus accumbens respond to liking and wanting showing there is differential mechanisms and processes involved in these experiences
Dopamine as a pleasure chemical
- There are separable components of motivation just like with liking and wanting
- Early theories of dopamine function suggested that dopamine was the ‘pleasure’ chemical
- that dopamine release in your brain
Still popular notion in the public and in media
Problem with pleasure chemical model
Dopamine - deficient animals still ‘like’ rewards
- they still find rewards pleasurable
Dopamine has nothing to do with the hedonic aspects of the reward
- opioids are important for this
It appears to be involved solely in the ‘wanting ‘ aspects of reward
What does dopamine really do - video
- it is involved in both teaching and motivation
- it signals when something is better or worse than expected and directs attention
- Dopamine increases salience to stimuli that predict pleasure
Incentive Sensitisation Theory
- dopamine responds to reward and predictors of reward.
- this theory suggests that when under the influence of drugs the dopamine system is sensitive to be hyper-responsive to environmental cues that are related to drugs.
So dopa responds to drugs but you also get powerful urgen when you see cues related to drugs as these drug related stimuli have gained incentive salience
disruption of brain control circuits
- drugs move up the survival hierarchy in dopa . Over time you begin to prioritise drugs over other things
- therefore you decrease your ability to be rational actor - dopa in cortex causes impaired judgement
Principles of effect treatment programs
- No single treatment is appropriate for all individuals
- Treatment needs to be readily available
- Effective treatment attends to multiple needs of the individual
- Treatment needs to be flexible
- Remaining in treatment for an adequate period of time is critical for treatment effectiveness
- Individual and/or group counselling and other behavioural therapies are critical components of effective treatment for addiction
- Medications are an important element of treatment for many patients, especially when combined with counselling and other behavioural therapies
- Addicted or drug-abusing individuals with coexisting mental disorders should have both disorders treated in an integrated way
- Medical detoxification is only the first stage of addiction treatment
- Treatment does not need to be voluntary to be effective
- Possible drug use during treatment must be monitored continuously
- Treatment programs should provide assessment for HIV/AIDS, hepatitis B and C, tuberculosis and other infectious diseases
- Recovery from drug addiction can be a long-term process and frequently requires multiple episodes of treatment
