Neurobiology of Addiction Behaviour

Question 1

what are the 6 factors in the ICD-10 criteria of dependence?

Answer 1

a strong desire to take the substance 
difficulties in controlling substance use 
a physiological withdrawal state 
tolerance 
neglect of alternative pleasures 
persistence despite evidence of harm

Question 2

according to ICD-11, what is gaming disorder characterised by?

Answer 2

impaired control over gaming
increased priority given to gaming over other activities
and continuation of escalation of gaming despite the occurrence of negative consequences

*must sufficiently impair daily life for at least 12 months

Question 3

in which pathway does dopamine acts as a motivating signal?

Answer 3

mesolimbic

*involves the VTA, nucleus accumbens and prefrontal cortex

Question 4

what study on gambling addicts suggests that a tolerance to reward develops?

Answer 4

non-addicted = increased blood flow to the striatum upon winning

addicts = significantly less response

Question 5

what is thought to be the cause of this reward tolerance?

Answer 5

dopamine D2 receptors are decreased by addiction

Question 6

in the context of drug addiction, describe the difference between positive and negative reinforcement?

Answer 6

positive = initial stages of drug taken driven by reward

negative = eventually drug becomes a thirst

Question 7

what is the role of the pre-frontal cortex?

Answer 7

helps intention guide behaviour
modulates the powerful effects of the reward pathway
sets goals, focuses attention
makes sound decisions
keeps emotions and impulses under control to achieve long term goals

Question 8

what is the effect of dopamine on the pre frontal cortex?

Answer 8

ability to update information within the PFC
ability to select new goals
the ability to avoid compulsive repetition of behaviour

*addictive drugs provide a potent signal that disrupts normal dopamine-related learning in the PFC

Question 9

what parts of the brain are critical in acquisition, consolidation and expression of drug stimulus learning?

Answer 9

hippocampal, striatum and amygdala

*learned drug associations can then cue internal states of craving

Question 10

what is the role of the orbito-frontal cortex?

Answer 10

provides internal representations of the saliency of events and assigns values to them
key creator of motivation to act
addicts show increased activation of OFC when presented with drug cues
hyperactivity correlates with self reported drug cravings following exposure to cues

Question 11

overall changes in the orbito-frontal cortex persist into abstinence - true or false?

Answer 11

true

Question 12

name the different circuits which are involved in drug abuse and addiction?

Answer 12

inhibitory control - PFC & ACG
motivation drive - OFC & SCC
reward/salience = NAc & VP
memory/learning = Amyg & Hipp

Question 13

in what ways may genetics effect addition?

Answer 13

effect the way we respond to drugs metabolically
behavioural traits that predispose us to take drugs
how rewarding we find drug taking
receptor levels eg low DRD2 = higher risk

Question 14

what is the effect of chronic stress on dopaminergic activity?

Answer 14

dampens it through downregulation of D receptors

this reduces sensitivity to normal rewards

Question 15

what part of the brain puts the brakes on the reward pathway and matures late so is vulnerable whilst developing?

Answer 15

pre frontal cortex

this is dysfunctional in addicted people