The cognitive neuroscience of addiction Flashcards
what is addiction?
Use psychoactive substances reg for variety of reasons
reasons to take alcohol
to relax
sleep
enhance social experiences
reduce anxiety/feelings of depression
coffee
to wake up
nicotine
foe experience
stimulant
social reasons
MDMA
improve social experience
reasons to take cocaine
to be more confident
focus o work
enhance social experience
reasons to take heroin
relax
feel belonging/safety
what % of alcohol users meet criteria for use disorder?
6% - most people don’t get addicted
drug/alcohol/tobacco addicts
experience intense cravings for desired substance and severe withdrawal symptoms when taken away
Can have profound effect on physical and/ mental health
Can have devastating effect on social life and fams
Addicts go to extreme lengths of obtain drug
Depends on how you define it
- Prescription depends on country you’re in
Compatibility with everyday life determining factor
drugs associated with addiction
o Nicotine o Alcohol o Amphetamine o Caffeine o Heroin o Cocaine o (Cannabis) o (Prescription drugs, such as painkillers and Benzo's)
drugs less associated with addiction
o MDMA
o Psychedelics
Muller et al (2011)
- Improved social interaction
- Facilitated sexual behav
- Improved cog perf and counteracting fatigue
- Fac recovery from and coping with psych stress
- Self-medication for mental problems
- Sensory curiosity - expanded perception horizon
- Euphoria, hedonia and high
- Improved physical appearance and attractiveness
cocaine
- Cocaine addiction associated with number of brain damage risks appearing minutes to hours after cocaine consumption, inc stroke in younger adults in early 30’s, seizures, lesions resulting in movement disorders
- More subtle pathology inc reduced volume of inferior portion of frontal lobe
heroin
Associated with broad range of neuropathologies inc reduction in grey matter
brain hypoxia (reduced ox avail)
cerebral oedema (water saturation)
stroke (loss of blood supply)
spongiform leukoencephalopathy (general loss of brain white matter - axons)
myelopathy (paralysis produced by spinal lesions
alcohol
- Strongly linked to Wernicke-Korsakoff syndrome
- Wernicke encephalopathy = general brain shrinkage
- Korsakoff syndrome is chronic ‘end stage’ - psychiatric diagnosis characterised by anterograde amnesia which can be treated with thiamine supplements
- Decreased grey matter
cannabis
- Yücel et al (2008) selected LT heavy cannabis-using men with average of 19.7 years of use with no history of other neuro/mental health complication and contrasted them with 16 control subjects
- Brain volume reduced un users in hippocampus and amygdala
cannabis and psychosis
- Longitudinal research assesses psychiatric status of youth prior to drug use, and then tests again in adulthood
- Odds ration shown for several studies reflect increased risk of diagnosis of psychotic symptoms in indvs who had engaged in heavy cannabis use compared to those who hadn’t
- Odds ratio 1 = groups have equal risk
- Average odds ratio was 2.09, indicating doubling of risk of psychotic symptoms with heavy cannabis use
causes of addiction
- Inter-indv variability in susceptibility to addiction
- 10-20% who use drugs addicted - vary depending on drug
- Similar estimates drawn from research on animal models of addiction - similar % animals systematically administered potent drugs end up preferring them to sucrose
- Genetic contribution to addiction about 50%