Noble et al found that the A1 variant of the DRD2 gene to be more common in alcoholics that non-alcoholics.
Comings et al found that 50% of smokers had the A1 variant of the DRD2 gene compared to 26% in non-smokers.
Comings et al (96) compared 222 US gamblers with 717 controls. 50.9% carried the A1 variant compared to 25.9%. Questionnaires revealed hat more severe gamblers were more likely to have this gene with 63.8% carrying it compred to 40.9% in less severe gamblers.
Noble has suggested that DRD2 is a 'reward gene', as people with the A1 variant of this gene have fewer dopamin receptors which are thought to be the pleasure centres of the brain. The lack of neurological stimulation results in people seeking substances whic induce stimulation.
Brandon's expectancy theory suggests that addiction develops due to the expectation that the benefits will outweigh the costs.
Connor et al (06) investigated 675 11-12 year old non-smokers over 9 months. Behavioural intentions were a good predictor of smoking initiation.
Griffiths conducted research with regular and non-regular gamblers and found that regular gamblers displayed irrational thoughts about their ability to control outcomes, produced irrational verbalisations and overestimated their abilities.
Langer (75) found that gamblers overestimate their ability and underestimate the amount of money they have spent.
Dalton et al found that exposure to movies with smoking increased the chances of initiation.
Robins et al found that US Vietnam war veterans who engaged in drug abuse did not show any signs of relapse when returning to the US as environmental cues (conditioned stimulus) were no longer present.
Wikler (48) observed that opiate addicts showed strong withdrawal symptoms when returning to locations where they had taken drugs.
Skinner (53) observed with rats, that the reward contingency that leads to highest level of responses (lever presses) was a variable ratio (VR). In such cases rats would be rewarded every Nth time but could not establish which particular lever press would be rewarded; this led to significant increases in lever pressing behaviour. This principle can be applied to gambling on fruit machines, in which a reward will come at some point after button pressing every Nth time.
Risk factors - personality
Nathan (88) claims that some people are more prone to addiction than others.
Cloniger (87): Tridimensional theory of addictive behaviour: proposed that 3 personailty traits that predispose individuals towards substance dependence:
- Novelty seeking (trying to engage in new experiences)
- Harm avoidance (which includes worrying and being pessimistic)
- Reward dependence (the extent to which an individual learns quickly from rewarding experiences and repeats behaviours that have been rewarded)
Francis (96) found that people who are moody and aggressive, these traits represent more neurotic/psychotic personality types using Eysencks scales. These individuals were more likely to display dependencies to alcohol, herioin, nicotine and BZs.
Risk factors - peers
Eiser et al (91) suggests that among adolescents, smokers tend to befriend other smokers and non-smokers tend to befriend other non-smokers.
McAlister et al (84) argues that smoking can be linked with peers' encouragement and approval, together with the message that smoking is an activity that promotes popularity.
SLT - Bandura (77) says that behaviours are learned through the observation of others and subsequent modelling of this behaviour. Young people are most likely to imitate the behaviour of those with whom they have the most social contact. Once they have started smoking, experiences with the new behaviour determine whether it persists.
Risk factors- stress
Driessen et al (08) found that 30% of drug addicts and 15 % of alcoholics also suffered from PTSD. The researchers found that exposure to 'mere trauma', in the absence of PSTD, was not sufficient to lead to an addiction.
Cloniger (87) suggested that there are two different kinds of alcoholics:
- Type 1 primarily drink to reduce tension
- Type 2 primarily drink to relieve boredom
Therefore stress ay explain vulnerability to addiction for some (type 1s) but not all people.
Risk factors - age
Berndt (79) found that anti-social peer conformity peaks at 15 years.
Shram (08) measured age differences in neural responses to actue nicotine administration and to the rewarding and aversive effects of nicotine in adolescent and adult rats that self administered nicotine. Nicotine was found to have a greater activity effect on the neural structures of adolescents, who were more sensitive to the rewarding qualities of nicotine, but less sensitive to the aversive effects.
Signorelli (90) reviewed US tv and found that characters were 9 times more likely to smoke in 1964 than in 1982, which conincides with a reduction in incidence within society.
Friend and Levy (02) reviewed the impact of anti smoking media campaigns in the US. They observed that well-funded and utilised campaigns combined with tobacco control programmes led to a reduction of smoking in adults and youths.
Wakefield et al (03) found that media can help shape and influence the social values of society towards smoking, the habit and associated health risks.
Hyung-Soek et al (07) found that negative media representations of gambling led to a shift in viewers' attitudes and perceptions so that they were more negative.
Merserlian et al (07) researched the effects of social marketing for gambling prevention in adolescents. They found that the use of rea life examples and emotional stories led to raised awareness. P's also reported that they would recommend this approach to promot gambling prevention.
Theory of planned behaviour
Winge (03) found that the TBP can be used to successfully treat addictive behaviours, such as teenage smoking.
Ogden (04) reports that there is a lack of consistent evidence to support the contribution of 3 factors. In addiction, Ogden highlights that the self-report measuresused are subject to considrable demand characteristics. Furthermore, data only provides a snapshot reflecting that moment, which might not represent someone's addictive behaviour.
Godin et al (06) examined the extent to which the TPB could explain smoking intentions and behaviours in adults intending to give up smoking. Data wa collected using questionnaires and interviews. P's er surveyed at the start and 6 months later. The researchers found that the 3 elements of TPB helped to explain intentions, whereas only perceived behavioural control was the most important predictor of ultimate behaviour, as predicted by the model.
Agonist maintenance - synthetic drugs are used to prevent withdrawal symptoms.
Narcotic antagonist - a drug which blocks the effects of opiates.
Hollander et al found that in a sample of 10 gambling addicts treated with SSRIs showed greater imporvements than a control group. HOWEVER research done by Blanco et al failed to replicate Hollander's findings with a larger sample of 32 p's.
UK statistics reveal that there were more that 300 methodone related deaths in 2007, which might be attributed to the unsupervised administration of the drug. While being 'less addictive' then herion some addicts become reliant on methodone.
Ladoueur et al randomly allocated 66 pathological gamblers to a CBT group or a waiting list. 86% were no-longer classed as pathological gambler folling the treatment.
Sylvain et al reviewed treatments which focused on addicts' cognition, including relapse prevention and found that gamblers made progress and this was maintained after a 1 year follow up.
Luty (03) claimed that psychotherapy is not effective. It can be difficult to ascertain the impact that the therapy has on outcomes, as PT is usually accompanied by another form of intervention.
Public health interventions
Russell et al (79) found that accross 5 London based GP practices 2139 patients were given differing degrees of advice regarding quitting smoking. They compared the effectiveness of the advice:
- Smokers were given a follow up interview at 12 months after they initially consulted their doctor about quitting: 0.3% had quit and lasted.
- Smokers who filled in a questionnaire about their smoking habits and got a follow up at 12 months: 1.6% had quit and lasted.
- Smokers who were advised to quit by their doctor, filled in a questionnaire and were given a follow up: 3.3% had quit and lasted.
- Smokers were advised by doctor to quit, given a leaflet with tips for quitting and a follow up: 5.1% had quit and lasted.
Furthermore, in a follow up study by Russell et al (83), rates of abstinence were increased to 8.8% in the leaflet condition when combined with treatments of nicotine gum.
Ogden (07) points out that if all GP's advised their smoker patients to quite this would result in half a million ex-smokers a year in the UK.