The use of biological interventions in reducing addictive behaviour

Black: AO1 - Description
Blue: AO2 - Evaluation - studies
Red: AO2 - Evaluation - evaluative points/IDAs
Purple: My notes/hints/tips

Varenicline is a prescription medication used to treat nicotine addiction, functioning as a partial agonist for nicotine receptors – stimulating them more weakly than nicotine itself. It both reduces cravings for and decreases the pleasurable effects of nicotine, helping people to quit smoking. Varenicline is usually administered orally, in tablet form.

In a double blind trial, Gonzalez et al (2006) found 44% continuous smoking abstinence during the last 4 weeks of a 12-week treatment in participants taking varenicline, compared to 18% of placebo-treated subjects and 30% of bupropion-treated subjects. After a year, the varenicline group had significantly increased prolonged abstinence compared to other treatments – over double that of a placebo, and slightly more than bupropion. This suggests that varenicline is an effective method of treatment, helping just under half of smokers quit in the short-term, and about a fifth in the long-term.

The fact that they looked at the effects of varenicline over a year, rather than just in the short term, makes this study’s results more valid – showing that varenicline is effective at prolonged rehabilitation from smoking rather than just short-term abstinence.

That 18% of patients managed to quit in the short-term via placebo treatment brings the effectiveness of the drug into question, suggesting that there is more to drug therapy than just biological mechanisms – the belief in having a drug to treat their addiction made them more likely to successfully quit. We cannot definitively say what proportion of those who successfully quit, quit due to the varenicline's effectiveness, or due to the placebo effect.

Aubin et al (2008) compared participants receiving varenicline to those receiving NRT, Nicotine Replacement Therapy. Patients were either on transdermal nicotine patches for 10 weeks, or varenicline for 12 weeks. Prolonged smoking abstinence for the last 4 weeks of treatment was higher for varenicline than nicotine patches – 56% vs. 43%. After a year, rates of prolonged abstinence were still higher for varenicline – 26% vs. 20%. 

Brose et al (2013) compared varenicline and NRT, measuring abstinence using carbon monoxide readings. They found that varenicline was more efficient - 43% compared to 37%.

Unlike many other studies into biological interventions, this study used a scientific, biological and objective measurement of abstinence, rather than self-report surveys and questionnaires, which could give untrue or misleading answers due to a social desirability bias.

Nicotine Replacement Therapy is based around nicotine administration in ways other than smoking tobacco, such as chewing gum, nicotine patches, and e-cigarettes. Rather than acting as a nicotine receptor agonist, they administer nicotine without the multitude of harmful effects associated with smoking, such as lung disease and cancers from chemicals in cigarette smoke.

West (2014) surveyed nearly 6000 smokers in the UK who had tried to quit smoking without the aid of prescription medication or professional support. Participants who used e-cigarettes were 60% more likely to successfully quit than those who used over-the-counter NRT or willpower alone, suggesting that e-cigarettes are the most effective publicly available form of NRT. This effectiveness has been explained by them filling a psychological as well as a biological need – going through a very similar procedure to the action of smoking a cigarette fulfils both, whereas conventional forms of NRT just fulfil a biological need. 

However, it has been suggested that e-cigarettes could increase the risk of future relapse, as they do not break this psychological procedural behaviour pattern of “smoking” like other forms of NRT do.

However, a 2012 study by Harvard University suggested that NRT may not actually be that effective. Surveying nearly 800 adult smokers who had recently quit, they were asked whether or not they had used NRT, joined a quit-smoking program, or received professional help. One-third of quitters surveyed reported to have relapsed, and there was no difference in relapse rate between those who used NRT and those who didn’t, suggesting that NRT might not actually play a role in helping people quit. 

On the other hand, a Cochrane systematic review challenges this, suggesting that NRT may be effective after all – analysing 50000 people over 150 trials of NRT, they found that it increased the chances of stopping smoking from 50% to 70%, but found no difference in effectiveness between different types of nicotine administration method, e.g. e-cigarettes, patches, gum.