China is the world’s largest producer of cigarettes, with a production of 214.38 billion cigarettes in 2007, accounting for 42% of the world’s cigarette production. China is a major smoking country, with adult male smoking rates between 60 and 70%, while the nicotine and tar content of tobacco in China is relatively high, and thus may cause greater physical damage, according to statistics, 2 million people die each year in China from smoking-related diseases, from this point of view, smoking is a public health problem.
The reason for the widespread prevalence of smoking involves many biological, psychological and social reasons, among which the important reason is that nicotine in tobacco is an addictive substance, and from this perspective, smoking is an addictive chronic addictive disease. This lecture will explain the following aspects of smoking as a chronic addictive disease.
I. The concept of addiction
According to Webster’s New World Medical Dictionary, addiction can be understood as a chronic, relapsing state characterized by impulsive drug seeking (compulsive drug seeking) and the abuse of addictive substances (also known as drugs, psychoactive substances, substances, etc., such as heroin, alcohol, tobacco, etc.) accompanied by long-term physiological changes in adaptive brain cases, resulting in increased tolerance, somatic dependence, intense craving, and relapse.
We can understand addiction from a behavioral perspective as.
1. the addict has a strong desire to exercise a certain behavior, but the result is harmful;
2. If the person does not do it, the tension and anxiety will gradually increase;
3. Once the behavior is completed, the tension and anxiety are quickly and temporarily relieved;
4.After a period of time, such as a few hours, days or weeks, the desire to perform the behavior will reappear;
5, external and internal environmental stimuli can be conditioned to cause this desire;
6. The addict hopes to control the behavior, but repeatedly fails.
Addiction is widely used in the professional literature as well as in the general population, and is ambiguous. “a group of physical, behavioral, and cognitive phenomena in which the user uses the drug as a first need (priority) and forgoes what was previously considered important. The central feature of the dependence syndrome is the expectation (often very strong and difficult to escape) to use addictive drugs (which may be medical or non-medical), alcohol, or tobacco.
”The DSM-IV definition is similar and considers “a cluster of cognitive, behavioral, and physiological symptoms that indicate that an individual continues to use an addictive substance despite understanding the obvious problems associated with its use, and that self-medication results in increased tolerance, withdrawal symptoms, and compulsive drug seeking behavior” [8]. [8]. From these two definitions, it is clear that the behavioral features of dependence are loss of control, manifested by a strong craving for drug use as a first need and the willingness to do anything in order to use the drug; and the somatic features are increased tolerance and withdrawal symptoms. The loss of control can be understood as psychological dependence and the latter as physical dependence.
From a psychological point of view, any activity or substance that produces pleasure, i.e., something that produces a so-called positive reinforcing effect, may have addictive properties. According to the above descriptions and definitions, addictive behaviors can be roughly divided into two major categories as follows.
1. Addiction to chemical substances, which include sedative-hypnotics, alcohol, stimulants, opioids, and of course tobacco.
2. Behavioral addictions, such as internet, computer, shopping, gambling, etc.
Generally speaking, if we talk about addiction, we are referring to addiction to chemical substances, i.e. addiction in a narrow sense.
Second, the relevant factors leading to addictive behavior
The causes of drug abuse have been studied from various aspects with different conclusions. It is generally agreed that there are many relevant factors that influence addictive behavior and cannot be explained by a single model. Social, psychological, and biological factors are intertwined and play an important role in the initiation of addictive substance use, continued use, the formation of dependence, relapse, and recovery. For the convenience of description, they are divided into the following categories.
(i) Sociological factors
1. availability No matter how addictive the drug is, if it is difficult to obtain, there is less chance of abuse. From the Opium War to the early liberation period, China suffered from opium. After the founding of New China, the Central People’s Government issued a general order strictly prohibiting opium, mainly against those who smuggled, trafficked, cultivated and produced opioid substances, and by controlling the supply, the opioid abuse problem basically disappeared in mainland China. Before the reform and opening up, people’s living standard was low, and they could only maintain their food and clothing, and the supply of alcohol was tight, so the per capita consumption of alcohol and cigarettes was low. After the reform and opening up, the living standard improved rapidly, the supply of tobacco and alcohol was abundant, and all kinds of advertisements were everywhere, so it was inevitable that the consumption of alcohol and the production of cigarettes increased.
2. Family One of the early forms of human learning is imitation, and the earliest objects of imitation learning are often family members. Children and adolescents first see their parents and older siblings using tobacco, alcohol, and drugs, and get knowledge of this from them. Of course, a good family environment can prevent individuals from developing drug addiction.
3. Peer influence and social pressure The age when drug use begins often occurs during the “susceptible period” of psychological development – adolescents, who are a subcultural body with a common worldview and cognitive system, and at the same time have poor discriminatory skills and values that are easily influenced by the small group they are in, coupled with curiosity, thrill-seeking, or the desire to be fashionable. They tend to use addictive substances as a sign of adulthood, although the taste of smoking is not pleasant at first, but they do not hesitate to try it. Most drug addicts are also in this environment on the smoke.
4, cultural background, social environment Different times, different cultural backgrounds, the abuse of different addictive substances have different views and standards. For example, people who believe in Islam have a strong aversion to drinking alcohol, so of course the drinking problem in those countries will not be serious. One of the reasons that the Chinese are the world’s leading smokers is that they use smoking as a means of social interaction, and the low rate of smoking among Chinese women is due to the socially repugnant attitudes toward female smoking. Smoking is common among women abroad, and it is claimed that smoking among women is associated with women’s liberation.
(ii) Psychological factors
Even when drugs are freely available, only a fraction of people will use and become addicted. Therefore, some people try to find the influence of psychological characteristics of addicts and pre-addiction psychological state on drug abuse in order to reveal the psychological mechanism of addiction.
1, personality research famous psychologist Eysenck’s research found that smokers are more extroverted, our research found that smokers are more anxious and more sensitive.
2, the psychological reinforcing effect of addictive substances According to behavioral theory, psychoactive substances have obvious positive and negative reinforcing effects. Most psychoactive substances have the effect of increasing positive emotions, such as “a cigarette after a meal, more than a living god”, “a thousand glasses of wine,” the pleasure of drug use and social reinforcement of the use of psychoactive substances to play an enhanced role.
Addictive substances also have a strong negative reinforcing effect, such as “a drunkenness is the answer to a thousand sorrows”, “a boring cigarette”, “what is the answer to sorrow, only Dukang”, and drugs have a counteracting effect on negative emotions. The important thing is that, after addiction, the drug has a negative effect. Importantly, after addiction, as withdrawal symptoms occur, the addicted substance user cannot extricate himself or herself and must repeatedly use the addicted substance to relieve withdrawal symptoms. This is the strongest negative reinforcing effect of loss of self-control.
(iii) Biological factors
Research has shown that genetic factors play an important role in addiction. Even tobacco addiction and alcohol addiction, which are closely related to psychosocial factors, are no exception. For example, the heritability of alcohol dependence is about 60%.
Of course, there is a material basis for the formation of addiction, as there is a material basis for the psychological phenomenon of craving for addictive substances. The dopaminergic pathways in the ventral tegmental area (VTA), nucleus accumbens (NAc), prefrontal cortex (PFC), and striatum, as well as the dopamine pathways in the prefrontal cortex, amygdala (PFC) and striatum, are currently thought to have a material basis. (amygdala (AMG) and hippocampus) to the nucleus accumbens (NAc), which together constitute a dependent NAc-related circuitry. Studies have shown that this pathway is not only the neuroanatomical basis for individual, race-preservation-related behaviors of species, e.g., diet, sex, etc., but is also an important neural pathway mediating reward, motivation, and learning associated with addictive substance use [11].
Although different types of addictive substances have different pharmacological effects, their final common pathway is to act on the neural pathway associated with the vomeronasal nucleus, increasing the impulses of dopamine neurons in the ventral tegmental area of the midbrain, resulting in increased release of dopamine in the vomeronasal nucleus as well as in other regions such as the prefrontal cortex. Cocaine and amphetamines indirectly agonize dopamine receptors by inhibiting synaptic gap dopamine reuptake, whereas opioids may indirectly promote dopamine release by agonizing μ, δ and relieving the inhibitory effect of GABA neurons on dopamine. Nicotine indirectly promotes the release of dopamine by acting with nicotinic receptors.
III. Evidence that smoking is an addictive behavior
(i) Clinical evidence
As mentioned earlier, once addiction is established, somatic manifestations are increased tolerance and withdrawal symptoms, and behavioral manifestations are loss of control.
Clinical evidence suggests that almost every smoker has the experience of smoking for the first time is not well tolerated, and that the amount of cigarettes smoked is not large for a period of time at the beginning of smoking, and gradually increases with the age of smoking, with some even exceeding 60 cigarettes per day, which 60 cigarettes are completely intolerable for a non-smoker. After smoking addiction, not smoking is painful, manifested by the so-called withdrawal symptoms, such as inattention p heart rhythm blood pressure drop, increased salivation, headache, insomnia, irritability p increased appetite [5], so the main purpose of smoking is to prevent the emergence of withdrawal symptoms.
Once addicted to smoking, smokers “lose their freedom” and must ensure an adequate supply of cigarettes in order to stabilize, addicted to smoking or even bring two packs of cigarettes on the body, the most painful for the big smokers for places where smoking is prohibited, such as before getting on the plane, especially long-distance flights, very nervous, afraid of smoking addiction on the plane. The first thing off the plane is not to pick up the luggage, not to go to the toilet, but to rush out to smoke.
(II) Experimental evidence
In the study of addictive behavior, there are many experimental animal models that are more responsive to human addictive behavior, such as the self-administration model (self-administration model), as shown in the figure, the self-administration model uses the principle of operant conditioning, when the test animal can get a certain amount of drug after making the action set by the program. Since this model better simulates human drug use behavior, it has been widely used in addiction research. It has good reliability and predictability in assessing the reward and abuse potential of addictive substances. Drugs that have rewarding effects on humans can cause self-administration models in experimental animals, and the most easily modeled addictive drugs such as stimulants (e.g., amphetamines, cocaine) and opioids (e.g., heroin, morphine, etc.), nicotine can likewise be implemented for self-administration in experimental animals.
(iii) Neurobiochemical evidence
Nicotine binds to the nicotinic acetylcholine receptor (nAchR) in the central nervous system, causing a conformational change in the nAchR, opening of the channel, passage of cations, and a change in signal transduction, resulting in the release of dopamine from the voxels. This leads to a transient reward/satisfaction after smoking. For tobacco addiction withdrawal and craving, nicotine withdrawal gummies are often used clinically as a substitute and can provide relief from withdrawal symptoms and craving. In addition, the nAchR semi-agonist, Varenicline (Champix/Chantix,) is able to agonize the receptor and can also play a better role in the treatment of tobacco dependence [13].
IV.Summary
Smoking is an addictive problem, whether from a social, psychological, or biological point of view, whether from a clinical point of view, or from an animal experimental point of view. From a public health perspective, the burden of disease caused by smoking is far more serious than drug use due to the large number of people who smoke. Despite the tax profits generated by the tobacco industry for the government, studies have found that the total economic loss due to smoking is close to 300 billion RMB, or about 1.5% of the year’s gross national product.
Of course, the response to tobacco harm should be multifaceted and a systemic project, and we expect new methods of smoking cessation while social control is also an important measure.