Tolerance, Dependence, Reinforcement Flashcards
What are the 5 parts of the continuum of involvement with drug use?
1) occasional use
2) frequent use
3) physiological dependence
4) compulsive drug use
5) overwhelming involvement (addiction)
What is addiction?
A behavioral pattern of drug use that is characterized by preoccupation with the acquisition of the drug, compulsive use, and a high tendency to relapse after withdrawal
What are the 3 basic processes related to addiction?
1) tolerance
2) dependence
3) reinforcement
What is tolerance?
When repeated exposure to the same dose results in a lesser effect
True or false: with people with high tolerance, a higher dose is needed for the same effect or sometimes the original effect isn’t possible at all.
True
What is cross tolerance?
Development of tolerance to one drug that results in decreased sensitivity to another drug
What are 2 examples of drug pairs that can have cross tolerance?
1) barbituates & alcohol
2) cocaine & amphetamine
What are the 3 types of drug tolerance?
1) Pharmacokinetic (metabolic)
2) Pharmacodynamic (physiological)
3) Context-specific
What is pharmacokinetic tolerance (metabolic)?
The liver synthesizes more enzymes to break down the drug after being exposed for a length of time, and so all of the drug’s effects will develop tolerance because it is due to overall decrease in the concentration of the drug
What is pharmacodynamic tolerance (physiological)?
Involves adaptations in the way individual neurons respond to a drug—may involve changes in homeostasis or changes in receptor sensitivity; viewed as the brain’s way of keeping things within normal limits
What is down regulation and what type of tolerance is this?
1) reduction in the number of receptors
2) pharmacodynamic (physiological)
What is desensitization and what type of tolerance is this?
1) decrease in receptor’s ability to respond to changes
2) physiological
What is up-regulation?
The increase in number of functional receptors, pharmacodynamic
What is sensitization?
Increase in receptor’s ability to elicit changes
Tolerance to drugs that mimic the actions of neurotransmitters tend to do what at the level of the neuron?
Cause down-regulation & desensitization
Tolerance to drugs that decrease the actions of a NT tend to do what at the level of the neuron?
Cause up-regulation and sensitization
What is context specific tolerance or behavioral tolerance?
Tolerance caused by a learned adaptation to the drug; when a drug is taken in one environment but loses tolerance when taken in another
True or false: with context specific tolerance, people may learn to adapt to the altered state of their NS and therefore compensate for their impairment
True
True or false: drug tolerance always develops uniformly
False
What is the problem with alcohol and barbituates when talking about tolerance?
The beneficial and recreational effects of the drug may show tolerance, but the lethal effects do not
True or false: tolerance to the drug may happen to the desired extent, but a person may actually be more sensitive to the side effects
True
How is non-uniform tolerance also present in amphetamines?
There is tolerance to euphoria, but user can become more sensitive to psychotic-producing effects
Generally when talking about drugs, what is sensitization?
Increased response to same dose with repeated binge-like exposure OR less drug needed to achieve the same effect
What is drug dependence and drug abuse, and how are they different?
Drug dependence is when drug use causes uncontrollable moods that lead the user to use drugs compulsively despite the obvious adverse effects, and drug abuse is using drugs in doses or ways that result in adverse effects
What are the two types of dependence?
Psychological dependence and physical dependence
How can you know is a type of dependence is physical dependence?
The presence of withdrawal syndrome
What is withdrawal syndrome?
Set of defined symptoms associated with lower blood levels of a particular drug
The effects of withdrawal are _____ the effects of the drug
Opposite
How does withdrawal occur?
Due to changes in the NS in place in response to chronic presence of the drug; when the drug is removed the compensatory mechanisms are still in place and so imbalance results
True or false: the duration and intensity of withdrawal syndrome is highly correlated with the duration and intensity of the drug’s direct effects
True
Chronic use of a drug with a short plasma half life will induce a ________ but ________ lasting withdrawal syndrome.
Relatively intense, short
Chronic use of a drug with a long plasma half-life will result in a ______ abstinence syndrome that dissipates ______
Relatively weak, slowly
Which of the opioids has the highest severity of withdrawal?
Heroin
True or false: in order for withdrawal syndrome to occur, the body must’ve developed tolerance to the drug’s effects
True
Why is tolerance necessary for physical dependence?
Because tolerance involves the body producing compensatory mechanisms to counteract the effects of the drug and this is what leads to withdrawal syndrome when there is no longer drug in the system
What is the possible mechanism of tolerance for amphetamine and cocaine?
The drugs may induce depletion of NT which causes less effects upon additional administration
What is a potential mechanism of tolerance for nicotine?
Nicotine is slow to unbind and therefore might saturate receptors, causing them to desensitize (higher levels of nicotine may act as antagonists)
What is psychological dependence, and how does it come about?
1) compulsion or desire to experience the effects of a drug because it is pleasant or reduces discomfort
2) comes about because of rewarding effects of the drug
What influences psychological dependence?
The context the person is, so learning and memory
True or false: All abuse-prone drugs enhance brain reward or lower the threshold for reward
True
True or false: there are some drugs that produce no psychological dependence but will induce physical dependence and withdrawal
True
What types of drugs have minimal addictive potential?
Psychotherapeutic drugs like antidepressants and antipsychotics
What is reinforcement?
Something that strengthens a behavior
How do we see examples of reinforcement in the lab with animals?
Mice will continue to press a lever if that means administration of the drug
Are drugs that rats will administer considered to be positive or negative reinforcers? And what type of dependence in humans is this type of reinforcement likely to lead to?
1) positive reinforcement
2) psychological dependence & likely addiction
Until the 1950’s, what was addiction thought to be?
Just a human problem of irresponsibility and immorality b/c at this time addictive behavior could not be produced in animals
What was the problem before the 1950’s that was the reason for lack of success in the lab for showing addiction in animals?
Oral administration of drugs, animals couldn’t associate it with effects (they could become physically dependent but wouldn’t do it on their own)
What technology in the mid 1950’s allowed scientists to show that animals could associate drug consumption and relief of withdrawal symptoms?
intravenous drug infusions
True or false: even animals who were not physically dependent would still administer small doses of morphine.
True
True or false: Animals will self-administer drugs that do not cause major physical dependence.
True
If an animal will self administer a drug that does not cause major physical dependence, then what can you say about that drug?
It is acting as a positive reinforcer
What is the positive reinforcement paradox?
The fact that drugs will continue to act as positive reinforcers despite causing unpleasant consequences
Describe how the motivation control system works.
Reinforcement system works by activating the motor loop in response to a stimulus like hunger. Past behaviors from learning and memory centers contribute to this loop. Kitchen & food example.
What five brain areas are involved in reinforcement and reward?
1) nucleus accumbens
2) VTA
3) basal ganglia
4) hippocampus
5) prefrontal cortex
Virtually all drugs of abuse target the reward pathways of the brain, but which synapse is particularly targeted?
The dopamine neurons that project onto the NA from the VTA
All addictive drugs produce an increase in dopamine where?
the NA
What is the role of the basal ganglia in the reward system?
Increases motor output to produce an overall increase in behavior
What is the role of the hippocampus in the reward system?
It tells the NA where we are and what is happening around us
What is the role of prefrontal cortex in the reward system?
Gives the NA several options for behavior
Why doesn’t everyone who tried a drug become addicted?
Genetic factors, sociological factors, psychological factors
What is the role of genetics in dependence and addiction?
They contribute more to drug abuse than use, but children of alcoholics for example are more likely to become alcoholics; possible inborn difference in NT systems may contribute to drug-seeking behavior
What is the role of sociology in dependence and addiction?
Weak family involvement related to drug use, religion correlates to non-abuse, prior exposure to substances also contributes
How does prior exposure affect the drug use of individuals?
Exposure to licit substances such as alcohol or nicotine increases the likelihood of using other illicit drugs such as cocaine, heroin, or LSD
What is the role of psychology in dependence and addiction?
Antisocial people or thrill seekers seem to be targets for addiction
