Risk factors and addiction: Genetic influences Flashcards
What is the influence of genetic factors in developing addiction?
They create a genetic vulnerability in addictive behaviours. This can explain why some people may become addicted after sampling a substance once and others can sample it without developing a full blown addiction.
What gene do gamblers inherit?
It has been suggested that pathological gamblers may inherit a faulty A1 DRD2 gene (Comings et al 1996) that, in effect, reduces the number of dopamine receptors in our pleasure centres within the limbic system. This means individuals with this variant are less sensitive to rewards and may seek out extra stimulating activities like gambling to compensate.
What is the reward deficiency syndrome? GENETIC INFLUENCES
Blum et al (1996) have called this the reward deficiency syndrome and have outlined how this creates genetic vulnerabilities in many compulsive disorders. E.g. 69% of a sample of alcohol dependent users and 51% of a sample of cocaine dependent users had this genetic variant.
GENETIC INFLUENCES - Research evidence?
Shields et al (1960) examined the concordance between 42 twin pairs that were reared apart. Only 9 pairs were actually discordant, so the remaining 33 were concordant showing how genetic similarity is a major factor in starting to smoke.
Kendler et al (1997) also found the concordance rates in MZ twins higher than DZ twins with alcohol addiction. 9000-strong sample and collected over 40 years.
GENETIC INFLUENCES - Alternative explanations?
The environment that rearing occurs in could influence behaviour such as smoking due to the fact that we can learn this behaviour from parents through so addiction can be due to intergenerational transmission. Hence addiction could be due to the nurturing received form the parents not the genes passed on by the parents.
This means the role of genetics in addiction is possible but not the only answer
GENETIC INFLUENCES - Diathesis stress model?
GENETIC factors can be used as part of the diathesis stress model.
For example we may have a genetic predisposition for addictive behaviour but only when certain triggers from traumatic life events occur, which may lead this genetic vulnerability to actually show itself in addictive behaviour.
This means a combination of genetics and environmental influences have to be considered as risk factors in addictive behaviour.
GENETIC INFLUENCES - Biologically deterministic?
It implies we have no free will and if we happen to possess any of the faulty genetic traits we are damned to be an addict for life. This is clearly not the case as illustrated by Blum et al (1996) and the A1 DRD2 variant. This genetic variant is not present in all cases of addictions and is common in the normal population (up to 20%) as well as those suffering from OCD and Tourette’s syndrome.
