Outline and evaluate the biological model of addiction (24 marks)
Addiction is the behaviour of repeating the same behaviour and therefore becoming a habit and pattern within an individual’s life, this behaviour can lead to a risk of disease and other social and personal problems. These habit patterns lead to immediate gratification (short term reward) which then has long term effects. Many individuals are able to recover from their addiction but there is a high risk of relapse occurring. The biological approach see addiction as being due to the individual them self, being an illness and addicts have a predisposed biological vulnerability. The model has 3 different aspects initiation, maintaince and relapse. Initiation is the stage in which the individual begins to become addicted which is then followed by maintaince whereby the individual continuous the addictive behaviour even with the occurring consequences. The final stage is relapse were the individual gives up the addictive behaviour but eventually sign’s and symptoms return and individual continuous these behaviours.
The biological model of addiction see addiction as occurring through 3 different ways Biochemistry factors, Genetics and reinforcement.
Research has been done in order to prove whether genetics may play a role in addictive behaviour. It is likely that multiple genes play a part in forming addictive behaviour rather than a single gene alone. For instance there is a link between tobacco smoking and genes which play a part in dopamine activity and cannabis having a link with genes in different parts of the brain. There have been many family studies to look at genetic transmission an example is Kendler et al (2000) who carried out twin studies to support the fact that genes play a part in addictive behaviour and found that there is nicotine dependency between 60 and 70 per cent. The problem with this is that the model can be seen as deterministic as it believe that individual can potray addictive behaviour due to genes and they are bound to become addicted. On the other hand it can be questioned whether individuals have control on their addictive behaviour and have their own thought which can play a part in stopping the temptation of becoming addicted.
The main chemical within these pathways is neurotransmitters which are chemicals that move within the gaps of the nerve cells and transmit messages. Chemicals may become blocked and this can lead to a change in the messages that the neurotransmitters are meant to send around the body. Biochemical factors is important because it’s all linked with how the brain works, many different substances and chemicals have different effects on the brain but the two major pathways within the brain is the Dopamine reward system and the endogenous opioid system. Dopamine is important for mood, emotion reward and is linked to the motivational process in the mesolimbic system. Normal dopamine within the mesolimbic system is active and releases a small amount of dopamine and is able to maintain a stable mood. Altman et al (1996) found that the consumption of alcohol and nicotine would affect the nervous system and increase dopamine levels and individuals who become addicted have inherited a sensitive mesolimbic dopamine pathway. It can be argued that through this the biological model is too simplistic as many individuals are able to take alcohol and nicotine and not neccdesrly become addicted and other factors are not taken into consideration. The biological model therefore needs to take in other factors e.g.: - envormental as this may play a part in an individual to fulfil the genetic predisposition. Many individuals are able to overeat and binge drink and revert back to normal everyday drinking and eating and so are able to balance neurochemical’s were the reinforcement system can tell control this behaviour and tell us to stop.
High levels of dopamine within the body can lead to addictive behaviour, Noble (1991) found that A1 version of DRD2 appears to be reduce dopamine receptors in ‘pressure centres of the brain, this can lead to higher risk of alcohol abuse to compensate the low levels of dopamine. If we compare two genes, one gene may not be adapted to enough dopamine in there system and another individual may have normal dopamine level. In order for the individual who feels that they do not have enough dopamine they feel the need to take drugs. A study that focused on genetics causing addiction was Overstreet et al (1993) who found that different genetics strains of rats demonstrated difference in levels of liking for alcohol, suggesting that preference for alcohol is under genetic control. It can be argued that the reason why the genes may have been mutated was due to drinking alcohol and not the gene being the main cause. A study that supported overstreet et al was Higuchi et al (2006) and reported that animal studies have shown that MPD2 gene prediction to alcohol dependency. The problem with both these studies is that they are animal studies and so therefore cannot be generalised to Humans but it brings in new ideas which could eventually lead to similarity between different animals and humans.