Biological influences on addictive behaviour

Genetics-

lerman et al- found a link between tobacco addiction and gene that regualtes dopamine

comings et al- found a link between other drugs like cocaine and heroin to a gene in a different brain system

Merikingas- 36% of reletives of individuals with an alcohol use addiction also develop a disorder

there are several supporting studies but it is impossible to separate the nurture/nature

Twin studies have found evidence of a genetic componant

Kendler- heritibility of nicotine dependence is 60-70%

Heath- heritibility of alcohol addiction 39-60%

Koob and Le Moal- changes occur in the brain system as a result of taking psychoactive drugs

if drug taking stops these adaptions are no longer needed an the brains homeostatis is distrupted

explains why people build a tolerance to drugs and need to increase dosage to gain same effects

also explains why withdrawal symptoms occur

The dopamine reward system- in the mesolimbic pathway cells produce spontanious bursts of dopamine to maintain stable mood

Altman- has found that alchol and nicotine affect the nervous system by increasing dopamine levels and improving mood

Liebman and cooper- those who are more susceptible to addictions might have inherited a more sensitive mesolimbic dopamine pathway

The endogenous opioid system- the opioid systems are activated in states of pleasure and can be directly stimulated by addictive drugs like nicotine and alcohol and heroin

Naltreone has been proven to help alcohol addiciton as it blocks opioid neurotransmitters (enkephalin and endorphins) and stopping the rewarding effects of alcohol- proving a genetic cause