I have problem of my essay structure.  
  
## How can psychology influence people's health?

  
  
People's health is not only influenced by physical illness and disease, but also by psychological factors. According to WHO (1948), health is defined as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity". The causes, progression and treatment of illness can be affected by psychological, behavioural and social changes (Naidoo and Wills, 2000). In this day and age, many people suffer from a different degree of health problems which affect their daily life, the ability to work or relationships. Most of those health issues are affected by addiction and stress. This essay will focus on how psychological and behavioural changes affect health including addiction, eating as well as mindfulness for improving health. Individuals with genetic vulnerability may tend to have negative thinking which increases the risk of mental disorder. For example, depression on its own may not cause liver problems, however, people who are depressed may be more likely to have alcohol abuse, resulting in liver damage. Understanding the relationship between the biological, behavioural and social impacts can help to understand physical illness and promote general well-being (The British Psychological Society, 2011).  
  
Addiction is a collection of behaviours and usually defined by its general features, which are difficult to define by its mechanism. Griffiths (2005) claims that addiction can be identified by different features including an increase in craving and tolerance; the experience of withdrawal with mood modification; persistent harmful behaviour; attempt to stop and relapse. The cause of the addiction is when an individual cannot control their behaviour due to inherent physiological or psychological vulnerabilities. Drug addiction, in particular, is likely to cause physical illness and mental disorders. It is an evidently self-destructive behaviour and it is firmly proven by many studies (National Institute on Drug Abuse, 2017). Some people place a greater emphasis on the susceptibility of the addictions due to the genetic makeup of personality traits, but also environmental stimulation, such as stress (Waqar, Badar and Shoeb, 2014). Addictive behaviour triggers psychological, physiological and neurological changes of the brain and the body, which can enhance the addiction (Monti, Rohsenow and Hutchison, 2000). Since the decision process of addictive behaviours prioritises immediate pleasure over long term negative impacts, initial use occurs (McClure et al., 2004). However, learning is crucial in terms of the occurrence of addiction which is a result of drug abuse over time and maintain the behaviour. (Ref) Drug addiction has a positive reinforcement effect which means continue repeated use after initial use, and relapse happens even though they attempt to stop the addiction. This cycle is supported by the positive reinforcement and consequence of taking the drugs (Wise and Koob, 2014). Repeated use of drugs often leads to the surge of the higher dosage. Weeks and Collins (1987) found that the stronger or higher dose of the desired drug is more rewarding. Drugs can increase the sensitivity of the reward circuit. On the contrary, the withdrawal of drugs decreases sensitivity and is aversive. This involves the process of negative reinforcement which also causes addiction. Individuals taking drugs repeatedly do so to avoid unpleasant feelings of stress or withdrawal. This is more likely to cause long term problems with drug abuse than the use of drugs for a pleasurable feeling (Wise and Koob, 2014). However, Lawton et al (2007) suggest that many of the most health threaten behaviours may not be reasoned but depend on the feeling of happiness or relaxation to some extent. This is supported by Lawton, Conner and McEachan (2009), which reported that affective attitudes are the more effective predictors of behaviour than cognitive attitudes.  
  
Food addiction plays a crucial role in nutrition, causing overnutrition. Obesity and related health issues are mediated by uncontrolled overeating. It can also lead to depression because of poor body image, overweight or obesity (Ayaz et al., 2018). Food addiction is a similar psychological process underlying the mechanism of addiction to drugs. A study revealed that both substance use disorder and food addiction have the same biochemical process (Volkow, Koob and McLellan, 2016). The reward system in the brain is activated when having addictive behaviours such as alcohol or drug use. Dopamine is released and regulates emotion and motivation. Very similarly, the dopamine reward centre is also triggered by eating, increasing the pleasure of food and desire. According to Volkow et al (2016), the pleasure of eating, particularly sugary and fatty food triggers the same reward responses as drug addiction, which can motivate an individual to repeat the behaviour even if it is harmful to their health.  
  
Obesity is the adverse consequence of excessive eating which is not purely caused by physiological hunger and physical intake of high calories food, also has psychological causes, feeling hungry even with a full stomach. People eat because of physiological cues related to an empty stomach that is referred to as internal cues (Vartanian et al., 2017). However, Franken (1994) reported that cue of associated food makes people feel hungry even their stomach is removed. Such hungry feeling can be triggered by external cue including normative and sensory cues which can also induce hunger. Normative cue such as portion size indicates the food consumption level while sensory cue such as smell, or taste refers to the pleasure of food (Herman and Polivy, 2008). Satiety is not necessarily depended on the amount of food intake but rather determined by norms and expectations. An experiment conducted by Wansink, Painter and North (2005) demonstrated that people ate 73% more soup using an imperceptible self-refilled bowl than a normal bowl. Those participants did not realise eating more and without feeling more sated in the experiment. On the other hand, the presentation of sensory cues significantly raises people's desire to eat even if not hungry. The stimulation of taste and sight prone to trigger people to eat more (Lambert et al 1991). Obese people are less responsive to internal cues but more to external cues than others. They are more likely to eat even if no stimulation of physiological cues (Schachter, 1968). The other updated study also suggested that obese individuals tend to be influenced by sensory cue than others while normative cues affect everybody (Herman and Polivy, 2008). In addition, a social cue is also an external cue which affects the eating pattern. People prone to consume more food when they eat with others compare to eating alone. According to Redd and De Castro (1992), the research showed that the participants consumed 60% more food when eating with others than those eating alone. Thus, an increase in the awareness of external factors may make it easier to attenuate the negative effect on overeating and achieve better health.  
  
Stress is a key psychological risk factor that initiates addiction, changing in eating habits and thus unhealthy lifestyle. Stress circumstance itself is not detrimental. How individuals interpret and cope with the event is fatal (Lazarus, 2006). Chronic stress minimises the volume of grey matter in the brain which involves cognitive and stress regulation. Stress shuts down part of the prefrontal cortex that is associated with deliberative cognition, leading to less reflective. The stimulation of alcohol, drugs and overeating are some of the ways for individuals to deal with stress (Grant et al., 2011). Kandiah et al (2006) study indicated that 81% of subjects changed appetite due to stress, of these, 62% experienced an increase in appetite. At the meantime, those participants were more likely to eat sweet or high calories food. This can explain why stress may contribute to obesity. In order to have a healthy life, dealing with stress is crucial. Mindfulness is one of the psychological methods to deal with stress and has a positive impact on health. Mindfulness intervention has been shown to inhibit stress processing activities and modulate the reactivity of the stress processing region in the brain, therefore, stress-reactivity responses reduced and relieve the stress (Creswell and Lindsay, 2014). Greeson et al (2011) found that increasing daily spiritual experiences helps to improve health-related quality of life; changing in spirituality and mindfulness were significantly associated with the improvement of mental health. However, the effects on biological health are not significant. Whereas psychologically healthy is beneficial to physical health indirectly.  
  
In conclusion, psychology and health outcome are intricately connected. Both mental health and physical health are important to maintain quality and healthy lifestyle. The causation of addiction, overeating and stress obviously have an impact on people's health. Mindfulness intervention raises the awareness and acceptance of individuals so that reducing stress-related disorder such as addiction and overeating, resulting in a healthy life.