Can I control my addictive behaviour?
Cognitive neuroscience of addiction
dysfunction in cognitive systems and their relationship too symptoms of addiction
policy implications
Question of whether addiction is a disease that causes symptoms or if there are differences in neurobiology that cause someone to be more susceptible.
drugs over activate pleasure centres of the brain/limbic systems
release dopamine via nucleus accumbens
closely associated with learning systems--> association of pleasure with drug related stimuli
strength of cravings associated with level of cue-related activation of limbic system
predictor of relapse
Methamphetamine
chronic use associated with several cognitive impairments
decreased EF
poor verbal memory
slowed processing speed
poor self control
reduced selective attention (more distractible)
decision making is biases towards immediate gratification
decreased cognitive flexibility (switching between tasks)
Use behaviour, frequency, quantity etc does not predict degree of impairment
potentially predicted by individual susceptibility
insula cortex critical to awareness of cravings
damage to this region increases likelihood of quitting
Low availability of D2 receptors--> high susceptibility to addiction
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drug induced increases in DA lead to optimal level of stimulation in people with low amounts of receptor. In those that have high amounts--> unpleasant experience of drugs
level of dopamine metabolism depletion worsens in chronic MA users
leads to high risk of developing parkinsons
predictor of relapse
associated with greater impulsivity for reward
Taq1A is gene that controls D2 receptor levels in brain, 2 copies leads to decreased D2 receptors
Direct stimulation eg drugs or indirect eg gambling
associated with likelihood of developing an addiction
Dopamine and self control
Parkinsons
associated with decreased IC and low dopaminergic tone
Habits
Impulsivity for reward
Acknowledged by DSM-V criteria for substance use disorder
loss of control is relative
Inhibitory control
top-down processing
anterior cingulate cortex detects need for IC
dorsolateral prefrontal cortex implements top-down control
amplify neural representations of task relevant stimuli
inhibit task irrelevant stimuli
repeated responding that forms context related associations
automatic responses that are relatively insensitive to changes in reponse
different to goal related repetitive behaviours as habits not always associated with goals as outcomes
habits persist even when positive outcome no longer occuring
repeated behaviour over time becomes less goal directed
formation initially based on rewards
maintenance associated with context cues (associated with reward)
interval schedules particularly effective
grow accustomed to behaviour not always resulting in award
premorbid risk
children of drug dependant ind. can have neurological deficits in Ic
drug related stimuli
attentional bias for drug related stimuli