Psychology of Drug Use & Abuse Flashcards
drugs use & addiction are
learned
learning is a permanent change in behavior as a result of experience
when you take a drug repeatedly
you learn how to administer it
your body gets better at processing it (tolerance)
your body starts to anticipate delivery of the drug & prepare for it (craving & withdrawal)
tolerance
decreased effectiveness or potency of a drug after repeated exposure
the need to use larger doses of the drug to achieve the same effects as when you first took it
effects of tolerance on your body
you don’t tolerate all the effects of a given drug at the same rate
E.g. morphine- nausea & vomiting-tolerance occurs very quickly, constriction of pupils- no tolerance
63 BCE- Mithridates V1 (King of Pontus)
He had been defeated by Pompey of Rome
His son had also just led a successful campaign against him
He tried to take his own life by ingesting poison- but it didn’t work
the king had spent his life afraid of being poisoned
throughout his life, he took increasing doses of well known poisons
his body learned how to metabolize the drugs
cross-tolerance
sometimes tolerance to one drug will diminish the effect of another drug
usually occurs between the same class of drug
opioid drugs & cross tolerance
all opioid drugs show cross-tolerance
if you develop a tolerance to heroin, you will also have tolerance to oxycodone & morphine
suggests these drugs are producing their effects by common mechanisms
pharmacokinetic tolerance
occurs as the body becomes more efficient at metabolizing a drug
fewer drug molecules reach their sites of action
increase of enzymes the body uses to break down the drug
drug does not reach the same peak levels & doesn’t last as long
when you experience pharmacokinetic tolerance
all effects of the drug are diminished
pharmacodynamic tolerance
physiological tolerance or cellular tolerance
arise from adjustments made by the body to compensate for effects of continued presence of a drug
result of pharmacodynamic tolerance
the body trying to maintain homeostasis
when a person first ingests a drug the body…
detects the drug and the effects on homeostasis- often the hypothalamus
responds by compensating to restore normal functioning
over time- the body gets better at restoring normal functioning
when you take a break from using a particular drug…
the compensatory process weakens
behavioral tolerance
you learn to function while impaired on a drug
the drug has less on an impact on your behavior
A Dr. with. an alcohol use disorder can still perform surgery
a person addicted to marijuana can still get a good grade on an exam
a mom with an addiction to valium can still react in an emergency
for tolerance to develop->
the influences of the drug need to be significant to the animal
ex. pain
ex. pain in tolerance and functional disturbances
unpleasant but really useful for survival
tolerance to morphine develops much faster when rats experience pain following injection
tolerance and functional disturbances
tolerance develops (or develops quickly) only when a drug places a demand on homeostasis
drug effects that aren’t detected (or don’t disrupt function)- don’t generate tolerance
withdrawal
physiological and psychological changes that occur when drug use stops
can be quite mild or quite intense (can cause death)
expressions of compensatory mechanisms to maintain homeostasis
withdrawal occurs because
the body “expects” delivery of a drug
starts to compensate to maintain homeostasis
BUT the drug is not delivered
withdrawal vs. toxic effects
there is a difference between withdrawal (compensatory effects) and toxic effects of the drug (hangover)
when you feel sick after a night out of excessive drinking
many of these effects are the result of toxic effects
dehydration & stomach irritation
after taking a large amount of cocaine- people often experience a “letdown”
period of depression as the body returns to homeostasis
compensatory response
dependence
when stopping a drug triggers withdrawal
people can experience withdrawal symptoms even when they do not take a drug compulsively
non dependence
some people can take a drug compulsively, but will not necessarily experience withdrawal when they stop
often substance specific
social smokers/social drinkers
tolerance and withdrawal
people can become quite tolerant of a drug, and fail to show withdrawal symptoms when they stop taking the drug
many people develop a tolerance to alcohol but do not show withdrawal
also more likely to happen when rate of elimination of the drug from the body is slow etc. THC (marijuana)
classical conditioning
learning that one thing predicts another thing
conditioned (conditional)
learned (no responding)
unconditioned
not learned (already responding to)
stimulus
noun/thing
response
verb/behavior
unconditioned stimulus
a thing I don’t have to teach you about
you will naturally make an unconditioned response
conditioned
the thing you learn
conditioned stimulus
neutral at the beginning of training
after training, you make a conditioned response
conditioned response (CR) often looks similar to the unconditioned response (UR)
Pavlov & drug use
apomorphine (short acting dopamine agonist)
in healthy dogs= restlessness, salvate, feel/act like its going to vomit
Pavlov gave the dogs the drug and waited a few minutes
just as the drug took effect, he played a tone (sound)
after several trials, the sound alone produced symptoms of the drugs (less intense)
CS
stimulus that predicts the US is coming
ex.the needle that is providing the heroin
CS in drug use
often the objects used to administer the drug/locations where drugs have been administered
cigarette lighters, bongs, needles, pill bottles, sight of the drug (cigarettes, cocaine, marijuana…)
exposure to these objects act as CS and predict the delivery of US
US in drug use
the drug itself
UR
unconditioned response (UR) to the presence of the drug= drug effects
alcohol= UR is intoxication
marijuana= UR is high
cocaine= UR is mania/grandiosity
CR
compensatory response- getting ready for the drug
the body compensating for the drug
often the opposite response
UR & CR with drug use
CR & UR can look very different
often- when presented with a CS
the CR is compensation for the drug
morphine example- what is CS, US, UR, CR?
ex. needle (CS)-> morphine (US)-> euphoria/resistance to pain (UR)
UR to morphine= analgesia (decreased responsiveness to pain)
CR to needle= hyperalgesia (increased sensitivity to pain)
conditioned tolerance
your body learns to tolerate the drug
Siegel (1975)
conditioned tolerance to morphine
analgesia
decreased responsiveness to pain
hyperalgesia
increased sensitivity to pain
paw lick latency test
put animal on a hot plate (uncomfortable- but not dangerous)
measure how long until the animal licks its paws
longer latency=
more analgesia (longer time until the need to lick their paws)
conditional tolerance in Humans
alcohol
a familiar drink (beer) compared to same dose of alcohol in a different drink (wine) or a drink that doesn’t usually contain alcohol (juice)
will produce more impairment when it is consumed in an unusual location (office) vs familiar (bar)
or an odd time of day (5 AM- at Purdue Breakfast club)
Siegel (1982)
on 30 consecutive days- rats were injected with placebo or heroin (on alternating days)
group 1: heroin w/ white noise in room A and a placebo in colony room
group 2: counter balance of group 1
group 3: injected on alternating days, in either room- but only with placebo
test phase
all three groups were given a large dose of heroin (15 mg/kg)
similarly/different/control
similarly tested group
heroin in the room where they usually received heroin
different tested group
heroin in the placebo room
control
was given heroin in either room
results
control group
different room group
same room group
control group
96% died of overdose
this dose was toxic to non tolerant animals
different room group
64% showed overdose
same room group
32% overdose
room as the CS
animals given the HIGH dose in the same room where they usually received the drug experienced conditioned tolerance
animals in the different room- did not compensate as well
learning- CS-US
in general- learning occurs faster when there is a short delay between the presentation of the CS and the presentation of the US
drugs are often more addictive when the effects (US) reach the brain more quickly following administration (CS)
administrative routes and speed of drug absorption
intravenous- hits blood stream immediately
inhalation
intramuscular
transdermal
orally
stimulus properties of drugs
state-dependent learning
shock-avoidance-escape experiments
state dependent learning
can a drug influence your ability to remember (or not) specific information?
overton
shock-avoidance-escape experiments
animals are placed at the bottom of the T
choose either R/L arm when they get to the top
if they choose incorrectly- receive a small shock
overton
administered pentobarbital (a mild barbiturate)
trained animals to avoid shock
animals could not avoid shock when given a placebo- & vice versa
discriminative stimulus
the stimulus that informs your behavior
Overton et al. administered pentobarbital & saline on alternating days
on drug days one response (eg left)= safety
on saline days. the opposite response (right)= safety
animals quickly learned to make a response depending on if they were drugged
craving, relapse, and withdrawal
you are exposed to a CS but do not get drug delivery
the case of California Do-Gooders
heroin-poster caused heroin relapse to increase
former addicts often experience withdrawal when
they go to places where they used to use
they see people they used to use with
they see/hear/smell things that remind them of the drug
relapse can happen even when
the used is no longer dependent on the drug
withdrawal symptoms will go away after repeated exposure to CS without the US (extinction)
compensatory response
extinction of drug use
presenting the CS without the US
responding to the CS declines over time
BUT- the information is not “forgotten” or “unlearned”
when CS is presented alone (repeatedly)- the compensatory response weakens… but…
reinstatement of drug use
what happens during relapse?
CS+US
response is often quite strong initially
often take a large quantity of the drug
often feel the effects- you are not compensating anymore
overdose is possible
use resumes
sensitization
reverse tolerance
when repeated exposure makes you more sensitive to a stimulus
it is possible for certain effects of a drug to increase with repeated exposure
administer low doses of a drug (cocaine, amphetamine, nicotine, alcohol, opioids..)- you can observe an “activating effect” (short term change in behavior)
with repeated doses there is an increase in these behaviors
at high doses=stereotyped behavior- invariable, repetitive movements, with no purpose- occurring for a prolonged period of time
Chippy stopped drinking for the summer while she was home from college. She went through the effects of withdrawal and when she came back to school she drank again after being exposed to the same stimulus but drank the same amount as she normally did. This time she gets really sick and suffers from alcohol poisoning. This is known as?
reinstatement
Operant conditioning of drug effects
Pavlovian/classical conditioning
Operant/instrumental conditioning
Pavlovian/classical conditioning
you learn that CS signals the US
you do not have to “choose” to act
sound of a lighter (CS)-> cigarette (nicotine) (US)
Operant/instrumental conditioning
animal must behave to receive a consequence
learn the relationship between behavior and consequences
reinforcement
increases the likelihood of a target behavior occurring again
punishment
decreases the likelihood of a target behavior occurring again
positive
does not mean good- means addition (adding something to the environment)
negative
does not mean bad- taking something away (removing stimulus from environment)
escape and avoid
negative reinforcement
dog jumping over to the other side of the crate when it is shocked on one side
positive reinforcement
taking heroin (Behavior) and getting the high (consequence)
negative reinforcement
taking and aspirin (behavior) to get rid of a headache (consequence)
positive punishment
drinking too much (behavior) makes you sick (consequence)
negative punishment
throwing out your drugs (behavior) makes you ill (consequence)
drug addiction when people first start taking a drug
it is usually because of the positively reinforcing effects of the drug
the high, social rewards, physical abilities
drug addiction once dependence sets in
you take the drug, in part, to avoid the effects of withdrawal
negative reinforcement
neuroscience of reward & addiction
meet the mesolimbocortical dopamine system
the brain’s reward system
begins in the midbrain (mesencephalon)
projects to the limbic system & prefrontal cortex
mesolimbocortical dopamine system
initiates in the ventral tegmental area
the medial forebrain bundle (mesolimbic dopa pathway)
nucleus accumbens
dopamine & reward
virtually all abused drugs increase dopamine levels in Nucleus Accumbens (NA)
opiates, barbiturates, alcohol, THC, PCP, MDMA, nicotine, caffeine
the paradox of dopamine & drug use
PET scans reveal that chronic drug users have diminished dopamine release & # of receptors
Volkow (2004)
Ss Non-drug users were given a low dose of a stimulant (Ritalin)
those who had the most enjoyment- also had low numbers of the D2 receptors
those who had the highest number of receptors- found the drug unpleasant
survival related information (food/sex) increases dopamine in the NA (50-100%)
many drugs (and electrical stimulation) can increase dopamine 3-6 fold in NA
animals will press a lever for a release of dopamine in NA
will stop lever pressing if they are given a dopamine antagonist
drugs (and EBS) delivered to the NA (or medial forebrain bundle) when animal presses lever
1000s of presses/hour
ignore food/water/potential mates
reward deficiency syndrome (hypothesis)
it is probable that lowered dopamine receptors
life is less rewarding general for these individuals
drugs elevate the level of perceived reward
experimental support: Thanos 2001
trained rats to self administer alcohol
inserted a gene that increased D2 in the NA
as receptors increased, rats reduced alcohol intake
prolonged drug use leads to
measurable changes in brain function & structure
chronic amphetamine use
increased dendrite length & complexity in the NA and prefrontal cortex
prolonged drug use results in
reduced dopamine activity & deactivation of prefrontal cortex
frontal dysfunction
leads to trouble controlling behaviors, weighing reward/consequence- making it harder to control your own behavior
