Addiction Cycle Flashcards
What is the cycle of addiction?
A proposed model for the stages of addiction to explain the path it takes along with the changes and behaviours witness
What are the three stages of addiction?
Binge/Intoxication
Withdrawal/Negative Affect
Preoccupation/Anticipation
What is the binge/intoxication stage?
Use of substance and euphoric effects
At which time does the binge/intoxication stage take place?
Mins-hours after substance use
How is DA released in this stage?
Opioid receptor activation inhibits GABA interneurons in the VTA
This stops that GABA inhibition of the DA neurons in the VTA
There is then increased release of DA in the NAc
Koob et al 2009
Why is stage 1 thought of as “positive reinforcement”?
Increase in DA release perceived as pleasure
This is then a positive reason to take the substance again
Which allostatic changes occur due to stage 1 effects?
Brain attempts to normalise DA levels released by the substance
Does so by decreasing DA receptor numbers
There is then an increased threshold of reward
Normally rewarding things are then not pleasurable any more
Which brain regions are involved in the withdrawal/negative affect stage?
Basal ganglia and extended amygdala
What occurs in the extended amygdala after intoxication?
Activation of stress circuits
Which molecules are involved in produce state of anxiety in the withdrawal/negative affect stage?
CRF
NO
Dynorphin
Glutamate
Which neurotransmitters are downregulated in the withdrawal/negative affect phase?
DA
5HT
Why is stage 2 considered “negative reinforcement”?
Creates a negative experience for when not intoxicated
Encourages to seek again
Which brain region does the preoccupation/anticipation phase take place in?
PFC
Which triggers may set off the preoccupation/anticipation stage?
Substance itself
Stress
Associated cues
How may an ““associated cue” cause craving?
Brain linked the firing in response to the substance to this cue
For examples needles and heroin
