Addiction Flashcards Preview

pharmacology > Addiction > Flashcards

Flashcards in Addiction Deck (15):

Definition of tolerance?

Decreased response to a drug after continued use
Produced homeostatic mechanisms adapting to the presence of a drug.
Not necessary for addiction


Definition of dependance

Need to take a drug to avoid withdrawl symptoms, accompanies tollerance
Can occur in non-addictive drugs
Not nec for addiction


Definition of addiction

Continued drug use despite known adverse consequences
Compulsive drug seeking behaviour
Can occur in absence of tolerance and physical dependence


Definition of relapse

Resumption of drug use after trying to stop
May occur months or years after abstinence


What is the animal model used for self administration?

Animal presses lever to receive drug.
See how hard the animal will press lever to get drug=motivation
And how long will the animal keep pressing the lever after the drug has stopped being delivered


Animal model using conditioned place preference

Animal has option between area associated with receiving cocaine or area associated with receiving alcohol.


Animal model choice of drinking bottles

Alcohol or water
Animals prefer alcohol with sugar


Talk about the reward circuit of the brain

Drugs increase dopamine in NAcc
Essential for survival to make us eat and have sex
Drugs of abuse flood the circuit, expoliting brains own survival mechanism


Talk about reward and dopamine

Many addicts report that with addiction the substance is no longer pleasurable, ie. no more endogenous opiods
Dopamine is released with reward signal
Unexpected rewards associated with most dopamine
If the reward is not obtained, dopamine neurones are inhibited (its disapointed)

Dopamine acts a learning signal
Wanting vs liking


Dopamine-mediated reward learning ensures:

Learn about reward environment
Highly motivated to obtain them
Reinforces repeated behaviour


Dopamine circuit, mesolimbic

Produced by ventral tegmental area
Released in nucleus accumbens

See very nice diagram in lecture notes


How do psychostimulants interact with dopamine system?

Block or reverse function of transporters
Increasing abundance of dopamine in synapse

Opiods, cannabis, ethanol, benzos inhibit cells which inhibit da release

Nicotine activates neurones which release dopamine

Ethanol directly activates neurones which release dopamine


What suggests there is something other than dopamine having an effect?

People dont abuse l dopa
Mdma is not addictive, this increase da
Antipsychotics cannot treat addiction
Addicts have lower levels of endogenous da than non addicts

Pfc and impulse control


Cycle of addiction

1 increased risk taking behaviour due to impaired pfc and executive function
2 initial drug taking, da release
3 long term changes in mesolimbic system
4 loss of behavioural control
5 crisi leads to desire to quit, detox
6 craving may lead to relapse


Why doesnt everyone who tries drugs become addicted?

Genetic factors