Addiction - Explanations For Nicotine Addiction (Brain Neurochemistry Etc.) Flashcards
What is neurochemistry?
Chemicals in the brain that regulate bio & psych functioning
What is dopamine?
A neurotransmitter, has an excitatory effect & is associated with pleasure.
What condition are unusually high levels of dopamine associated with?
Schizophrenia
What condition are unusually low levels of dopamine associated with?
Parkinson’s disease
Who came up with the desensitisation hypothesis of nicotine addiction?
Dani & Heinemann
What is the key neurotransmitter in the desensitisation hypothesis of nicotine addiction?
Acetylcholine
What is the name of the receptors which are activated by acetylcholine or nicotine?
Nicotinic Acetylcholine receptors (nAChR)
What happens when nAChRs are stimulated by nicotine?
The neurons release dopamine
What pathway does the dopamine travel down?
mesolimbic pathway to nucleus accumbens -> triggers release of dopamine into frontal cortex
mesocortical pathway -> released directly to frontal cortex
What are the mesolimbic & mesocortical pathways a part of?
the brain’s dopamine reward system
What does nicotine do to the brain’s reward system?
It powerfully activates it -> results in pleasurable effects e.g. mild euphoria, alertness & reduction of anxiety
How are the pleasurable effects of nicotine associated with smoking?
Operant conditioning
What happens when an individual stops smoking?
nicotine disappears from their body -> nAChRs become active & dopamine neurons resensitise and are available (upregulation)
How can neurochemistry explain the symptoms of withdrawal, dependence & tolerance?
During resensitisation nAChRs become overstimulated by acetylcholine (no nicotine) -> most sensitive
to avoid unpleasant physiological & psychological withdrawal state -> go through constant cycle of daytime downregulation & nighttime upregulation (creates longterm desensitation of nAChRs) -> dependence
continous exposure causes physical changes to the brain (decrease in number of active receptors -> tolerance develops)
EVALUATION: What research support from McEvoy et al supports the desensitisation hypothesis of nicotine addiction?
Studied smoking behaviour in people with schizophrenia who were taking Haloperidol (antipsychotic) -> dopamine antagonist
People taking the drug showed increase in smoking (form of self-medication ) -> shows dopamine has key role in the neurochemistry of nicotine addiction
EVALUATION: What real world application is a strength of brain neurochemistry as an explanation of nicotine addiction?
Nicotine replacement therapy -> developed after nicotine was identified as addictive & had affects on nAChRs
NRT products (gum/patches etc) deliver controlled dose of nicotine -> binds to nAChRs and mimics effects
Helps with cravings and gradually reduce withdrawal symptoms -> greater understanding neurochemistry led to effective treatments
EVALUATION: What does Gilbert say about the limitations of the brain neurochemistry explanation for nicotine addiction relating to withdrawal symptoms?
Argues withdrawal symptoms depending on amount of nic in body is not strongly correlated -> depends on environment & personality (people who score high on the personality of neuroticism generally experience worse withdrawal symptoms then those who are emotionally stable) -> withdrawal effects can be explained in other ways without reference to amounts of nicotine
EVALUATION: How can the brain neurochemistry explanation of nicotine addiction by biologically deterministic?
Suggests we become addicted due to chemical events regarding dopamine that is beyond our control (inevitable for smokers)
Some dont experience withdrawal symptoms/dependence & some find it easier to quit due to their personality
