Addiction (2) Flashcards
What is the definition of addiction?
state of compulsive drug use despite serious negative consequences such as medical illness, risk of significant life problems, and putting social valuables at risk
The substitution of drug rewards for
natural rewards suggests what?
neuropathology of addiction resides in the same neural system that mediates behavior for detecting, liking, wanting and acquiring natural reward.
A key aspect of drug addiction is what?
high relapse rate.
What is drug tolerance?
Decrease effects of a drug that develops
with continued use; first administration of a drug produces a characteristic dose-response curve; after repeated administration, curve shifts to the right, larger doses (risk of overdose) are needed to produce the same effect.
What is drug sensitization?
Enhanced effects of a drug that
develops with intermittent use. After intermittent administration of the drug the curve shifts towards the left, greater effects are achieved with a similar or lower dose.
Leads to long term changes in neural
circuitry; a key reason for the development
of salient incentive or “want” or “craving.”
What is innate tolerance?
Individual variations in sensitivity to a drug present before the administration; due to polymorphism in genes encoding drug receptors, and components of drug metabolism
What is Acquired Tolerance and Pharmacokinetic tolerance?
increase ability to excrete drug with the
time, leading to relatively lower plasma drug
concentration.
What is Pharmacodynamic tolerance?
Changes in drug-receptor interactions caused by: short term decrease in receptor # or binding affinity due to inactivation of receptor, internalization or degradation, and by long term changes in receptor # caused by alteration gene regulation
What is physical dependence and withdrawal?
Adverse physical symptoms and signs that result from the withdrawal of a drug, In absence of drug altered set point produces effects opposite of the drug, varies with diff drugs,
What causes physical dependence and withdrawal?
alteration in homeostatic set points to compensate for abused/misused drugs, drug-induced alterations in cell physiology and circuits; unmasked by drug cessation
Explain the concept of a reward?
Rewards (food, sex, cocaine) lead to “feel good” or “pleasure” sensation (hedonic)initiates learning process -> liking -> indentifying cues that predict avail., assign values and motivationstate (withdrawal early)-> increase want (incentive salience) -> positive reinforcement
What causes compulsion in addict?
sensitization (hypersensitivity) of component that mediates “Want (=incentive salience)”, neural substrate responsible is separable, yet interconnected, from neural subs. for pleasure/liking
Motivational behavior involves what processes? So it may involve higher centers such as what?
cognition, emotion, self-perception and
execution; PFC, amygdala, insular cortex, and dorsal striatum (caudate and putamen)
Sensitization of neural substrate for “want” is powerfully modulated by what?
earning and circumstances/environment surrounding drug administration (associative learning)
Rats, with electrodes in specific brain areas press a lever to self-administer electric stimulation or press lever to eat food. Which areas was stimulation preferred over food?
medial forebrain bundle, nucleus accumbens (NAc), ventral tagmental area (VTA), and lateral hypothalamus
What is conditioned place preference (CPP)?
rewarding properties of a drug are associated with a particular characteristics of a given environment
