Charles University in Prague Faculty of Social Sciences Institute of Economic Studies
BACHELOR THESIS
2010 Martina Mandelíková
Charles University in Prague Faculty of Social Sciences Institute of Economic Studies
BACHELOR THESIS
Adolescents Substance Use: Identifying Factors Influencing Alcohol Consumption among High School Students in the Czech Republic
Author: Martina Mandelíková Supervisor: Ing. Filip Pertold, M.A Academic Year: 2009/2010
Declaration of Authorship
I hereby declare that I compiled this thesis independently, using only the listed resources and literature.
Prague, May 20, 2010 Signature
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Acknowledgment
I would like to thank to my consultant, Filip Pertold, for his time and a great and very helpful tutoring.
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Abstract
This bachelor thesis focuses on indicating the factors, which influence the participation in adolescent substance use. Possibly important factors are identified based on the previous researches dealing with the same topic. The effect of these factors is then tested with the empirical model. This thesis deals with a dataset from the European School Survey Project on Alcohol and Other Drugs done at the Czech high schools among freshmen and juniors. Since the results in dependence on sex and class year are expected to be different, the regression is run separately. The most significant factors are for all cases: the smoking experience, the age of the first intoxication, and the share of friends who already consume alcohol.
Keywords: Adolescents, Substance Use
Abstrakt
Cílem této bakalářské práce je identifikovat faktory, které přispívají k užívání alkoholu mezi mladistvými. Z předešlých výzkumů na toto téma jsou vybrány faktory, které by mohly pravděpodobnost konzumace alkoholu nejvíce ovlivňovat. Jejich vliv je testován pomocí empirického modelu. Použitá data pocházejí z Evropské školní studie o alkoholu a jiných drogách, která proběhla v roce 2003 ve vybraných prvních a třetích ročnících českých středních škol. Vzhledem k tomu, že se dají předpokládat různé výsledky v závislosti na pohlaví a ročníku, regrese byla provedena odděleně pro jednotlivé případy. Jako nejvíce signifikantní vycházejí pro všechny případy: zkušenost s kouřením, stáří v době prvního opití a vysoký podíl přátel konzumujících alkohol.
Klíčová slova: Adolescents, Substance Use
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Table of content
Table of Content ...... 1 List of Abbreviations ...... 2 List of Graphs ...... 3 List of Tables ...... 3 1 Introduction ...... 4 1.1 Alcohol and Related Problems ...... 4 1.1.1 Alcohol in the Czech Republic ...... 5 1.2 Youth Drinking ...... 5 1.2.1 Czech Youth Drinking ...... 7 2 Determinants of Youth Drinking: Literature Review ...... 8 3 Construction of Model ...... 11 3.1 Methodology ...... 11 3.2 Empirical Model ...... 12 3.3 Limitations of the Model ...... 14 4 Data Description ...... 16 4.1 Data Source ...... 16 4.2 Sample ...... 16 4.3 Measures ...... 17 4.3.1 Variable Specification ...... 17 4.4 Descriptive Statistics ...... 20 5 Results ...... 23 5.1 Discussion of Results ...... 25 6 Conclusion ...... 28 6.1 Summary ...... 28 6.2 Implementation ...... 29 Bibliography ...... 30 Appendix ...... 35 Appendix I: Graphs ...... 35 Appendix II: Used questions ...... 38 Appendix III: Descriptive statistics ...... 41 Appendix IV: Results ...... 43 Appendix V: Bachelor Thesis Proposal ...... 45
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List of Abbreviations
EMCDDA European Monitoring Centre for Drugs and Drug Addiction ESPAD European School Survey Project on Alcohol and Other Drugs CSO/CSU Czech statistical Office LPM Linear Probability Model NHMRC National Health and Medical Research Council NIAAA National Institute on Alcohol Abuse and Alcoholism OLS Ordinary Least Square UIV Institute for Information on Education WHO World Health Organization
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List of Graphs
Graph 1. Adolescent substance use – comparison CR with the average of all countries participated in ESPAD 2007……………………………………………34
Graph 2. Czech youth alcohol use (past 30days) according to gender………………………35
Graph 3. Heavy episodic drinking (past 30days) of youth in CR ………………………….….35
Graph 4. Heavy drinking episods (5 or more alcohol beverages, more than twice in last 30days), in %, CR………………………………………………………….…….36
List of Tables
Table 1. Descriptive Statistics – full sample …………………………………………………………....40
Table 2. Descriptive Statistics – different groups …………………………………………………….41
Table 3. Estimation of drank last month – full sample ……………………………………………..42
Table 4. Estimation of drank last month – different groups ……………………………………..43
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1 Introduction
1.1 Alcohol and Related Problems
Alcohol is the most used drug in the world. It is mainly because alcohol is legal and socially acceptable in most countries (Keller and Vaillant, 2010)1. Majority of people drink alcohol, generally for enjoyment, relaxation and sociability. Most people belongs to group of moderate drinkers and at this level, alcohol causes only a few adverse effects (NHMRC, 2009). Actually, sensible drinking can even be beneficial for the health of adult (White, 1999) 2 . Unlike the moderate drinking, experiencing of severe or frequent intoxication negatively affect short-term as well as long-term health condition. Often alcohol abuse and alcoholism does not affect just health of the drinker, but also harms drinker’s family and friends, employer and the broader community. Even though, there is just a small proportion of people who consume alcohol at higher levels, the impact of this group on society is significant.
The society suffers from heavy drinkers mentally as well as economically3. It is not just the treatment of alcohol related to illnesses problems such as cirrhosis of the liver, or cancer of the oesophagus or stomach, which is costly. Drinkers are frequently predisposed to common injuries. All this health related trouble together with often physical and mental incompetence caused by intoxication rise to decrease in productivity and to higher absence from work. Among others, alcohol abuse increases crime-related costs as well as vehicle crash costs. Moreover, heavy drinkers and alcoholics are more likely to die prematurely (Harwood et al, 1998). Unfortunately, the burden of alcohol problems does not fall just on the abusers. It is primarily the rest of society, who bears these costs4.
The relationship to alcohol starts to develop during childhood. From the drinking habits in childhood is possible to predict some conclusion about the drinking level and about the health status in adulthood. Early initiation to drinking is associated with increase in the risk of alcohol dependency in adulthood. Persons who begin to drink at the age of fourteen or
1 Encyclopædia Britannica 2 Drinking during pregnancy is an exception from this rule. Even one standard drink a week can negatively affect the health of fetus (Keller and Vaillant; 2010). 3 The economic costs of alcohol problems in United States are in billions of dollars per year (Harwood et al; 1998) 4 Non-users have direct material and mental loss when they are victims of alcohol-related crime or car crash. Non-abusing public also pay the costs of health problems of drinkers through public health insurance. Moreover, the expenditures of government on criminal justice system or highway safety as well as lower tax revenues caused by lost productivity are often covered from social insurance. (Harwood et al; 1998) 4 younger have almost 40% probability they become abusers or alcoholics later in the age, whereas individuals who starts drinking at ages 20 and older have the probability just 10% (Grant and Dawson, 1997). Besides, continuous alcohol consumption starting in early adolescence has significantly negative effect on health later in the age (Aarons et al., 1999). It is impossible to protect the young people from the possible future dependency on alcohol without working antidrug policy. However, successful policy cannot be created without continuous observation of youth risk behaviour and its involvement in time. It is not an aim of this thesis to invent such policy, but to indicate factors, which influence young people’s decision to drink. I believe that knowing those factors is essential for inventing good alcohol abuse policy.
1.1.1 Alcohol in the Czech Republic The drinking prevalence in the Czech Republic is very high and the Czech society is very tolerable not just to regular alcohol use but also to extensive drinking (Sovinová and Csémy, 2003). This attitude not just negatively influences the risk behaviour of adolescents but also significantly decreases successful implementation of a functional prevention programs. The main problem ground in the disesteem of the health risks related to alcohol use, especially to extensive drinking. This unknowingness is not only problem of the Czech society, but also of the Czech government. It seems that the government only enjoys the income from alcohol to the treasury, but do not see the expenditures on the treatment of health-related problems. The problem of alcohol and the health of society are very relevant in the Czech Republic, because of the high alcohol consumption per head. It was 10.4 litters of pure ethanol in 2008 (CSO, 2009). The economic and social costs of alcohol are not known yet. However, the study of Social costs of alcohol, tobacco and illegal drugs in the Czech Republic in 2007 (Center for Addictology, 2010) is in process now. The results should be released in year 2011 and are expected to provide an economic lead for further intervention in this field.
1.2 Youth Drinking
Statistics from the last European School Survey Project on Alcohol and Other Drugs (ESPAD) report (Hibell et al, 2009) show repeatedly that early intoxication and binge drinking of adolescents is a common problem in many European countries. Indeed, it is not
5 problem just in Europe, but also in the United State or Austria. Moreover, the risky attitude to alcohol is spreading to teenagers in developing countries (WHO, 2001).
According to The 2007 ESPAD Report, the average from the surveyed countries5 is around 90% of high school students who have tried alcohol at least once in their lifetime, 82% during the past year and 61% in the last month. This statistics does not vary much from the year 1995 when the ESPAD started. Especially the figures for lifetime and past year drinking remain almost unchanged. The share of drinking boys in the last 30 days even decreased in comparison to year 2003. Unlike the quantity of alcohol consumed which increased in 2007. A trend of growth in heavy episodic drinking is observable particularly among girls. Boys have always consumed alcohol at higher level than girls have, but generally, the difference between boys and girls drinking behaviour is decreasing.
The growing tendency of young people to binge drinking is not very positive, especially when concerning the health status of youth. As mentioned in the Introduction the alcohol usage in adolescence has many potential health risks. Being more specific, alcohol, when consumed in childhood can for instance affect normal brain development, or cause hormones’ misbalance in young organism (NIAAA, 2006). In addition, alcohol consumption elevates the risk of psychiatric co morbidities, especially depression, anxiety or attention- deficit disorder (Turner and Gil, 2002). Negative effect on liver can also occur (Clark, 2001). Although it takes a long time to develop the alcohol related diseases such as cirrhosis, heart disease or cancer, at some adolescent heavy drinkers can appear a beginning of liver damage in early age (Newbury-Birch et al., 2009).
In any case, most health risks of drinking adolescents are connected with short-term acute effects of alcohol usage. Primarily, acute intoxication causes unpleasant health problems such as vomiting but in some cases, there is a risk of rapid development to coma with possible consequence of death (Lamminpaa, 1995). Generally, drinking leads to a higher risk of accidents and injuries and plays a significant role in many injury hospitalizations (Johnson and Richter, 2002). In a large extent, alcohol contributes to unintentional injuries, homicide and suicide, which are the leading causes of death among youth (Miller et al, 2007). Adolescents who consume alcohol are more likely to engage in a dangerous behaviour such as having a high-risk sex (Läuchli et al, 1996), driving impaired or committing a crime (Zhang et al;2002). Among others, drinking is associated with poorer performance at school, which can lead to academic failure (Bergen et al; 2005).
5 In year 2007 participated 35 European countries in ESPAD 6
1.2.1 Czech Youth Drinking The Czech Republic belongs to the countries with the highest rate of lifetime alcohol prevalence by youth. The statistics about drinking prevalence of the Czech high school students do not change much from 90’s. In the Graph1 is shown the comparison of the Czech students ESPAD score on alcohol, cigarette and other drug use with the average from other European countries. In the Czech Republic there are about 93% of high school students who drank alcohol in last 12month. It is more than 10% above the average of European countries included in ESPAD. Czech teens also consume alcohol beverages more frequently and in higher quantity than is the average among European youth. Share of adolescents with heavy drinking episodes differs across regions in the Czech Republic, but in most of them it is much higher than the average of other European countries (Hibell et al, 2007).
Alcohol-related problems are not rare among Czech young drinkers. Almost 16% of those who consumed alcohol during last year were in physical fight because of their own alcohol use. In consequences of drinking, 23% of drinkers had serious problems with their parents and about the same percentage had trouble with friends. About 17% had an accident or injury and 1.5% had to be hospitalized as a result of alcohol consumption. Alcohol usage end up in trouble with police for 7% of drinkers and 3% were victimized by robbery or theft. Alcohol was the reason why 12% of teen drinkers engaged in sexual intercourse without a condom and why 14% of them had sexual experience that they regretted afterwards. Above 18% of Czech young drinkers performed poorly at school or work because of liquor usage. More than 50% of the students who have ever tried alcohol in their life, have experienced at least one of the mentioned problems (Csémy et al, 2008).
From this statistics is clear that the drinking of Czech adolescent is an indispensable problem. Indeed, alcohol is a problem not just among youth, but also in the whole Czech society. However, changing the risk behaviour of adults is much harder than influencing the opinion on alcohol and drinking behaviour of adolescents. To be able to do that successfully, it is important to detect the factors influencing participation and intensity of substance use of adolescents.
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2 Determinants of Youth Drinking: Literature Review
Research on adolescent substance use has identified number of factors that influence the alcohol consumption of youth.
The adolescence is an important period in life, when the young people have to deal not just with many changes that happen in their organism (hormonal alterations, brain development) but also with the new environment after transfer from elementary to secondary school. The effort to ‘fit in’ and to be socially accepted by the fellows can have very negative influence on decision making concerning drinking behaviour and drug use in general. There has been found a significant correlation between adolescent alcohol usage and the drinking behaviour of friends (Ali and Dwyer, 2009; Harmon, 2007). From the age of 14, 15 years, the influence of parents decreases as the young people start to spend more time with their friends and accordingly increases the influence of peers. Therefore, peer effect has a great influence on alcohol consumption of adolescents.
Likewise, the role of regular drinking parents and siblings in adolescent substance use is not negligible. It has been found that the influence of drinking mother and drinking father on youth regular alcohol consumption is the same, but the relative risk of drinking parents is the lowest in comparison with influence of siblings and peers (Scholte et al, 2008). Generally, the role of parents lays more in the monitoring of adolescent and the shown approval or disapproval of alcohol use (Nash et al, 2005). The effect of regular drinking siblings is higher than of drinking parents, but depends on the age and sex of the sibling. Drinking habits of younger sibling does not seem to have any influence on youth alcohol usage (Vorst, 2007). Highest influence has the same-sex twin, but having the regularly drinking same-sex older sibling also significantly increases the probability of regular adolescent substance use (Scholte et al, 2008).
Engels et al. (2006) is concerned about the personality characteristics as an explaining factor for adolescent substance use. According to this study, young people with certain characteristics are more likely to engage in risk behaviour such as drinking and smoking. Teens, who were evaluated from their classmates as sociable and self-confident and those who were considered as aggressive and emotionally insecure usually smoke and drink more than their classmates with different characteristics. Poor sociability, on the other hand is associated with lower level of alcohol use or abstinence (Leifman et al, 2000). Important
8 behaviour predictor of regular heavy drinking is the tendency to deviancy and rebelliousness. Young people who are evaluated as radical and who show lower commitment to conventional values are more likely to consume alcohol in higher quantity and frequency (*Newbury-Birch et al, 2009)6.
Drinking behaviour of adolescents is also influenced by their expectancies about substance use. Intuitively, if the view of alcohol is mainly positive and the risk perception is low, then the adolescent is more likely to be a heavy drinker (Smith and Goldman, 1995). There is a reciprocal relationship between expected social facilitation of alcohol and drinking level – the higher the expectancy the higher the amount of alcohol consumed and vice versa. Usually in the adolescence, the social advantages of alcohol consumption are higher than the potential health problems caused by substance use. The underestimation of the risks is caused by the long-term development of the alcohol-related problems (*Harmon, 2007)7.
Among others, the age of beginning of substance use can be a good predictor of future drinking behaviour of young people. Generally, the earlier the individual starts to drink the higher is the risk of development of alcohol use disorders (Zeigler et al.; 2005). On the contrary, research done on the sample of US college students (*Newbury-Birch et al, 2009)8 showed that the later the individual had tried the first alcohol drink the lower its alcohol consumption is as a college student. Grant and Dawson (2002) reported that the probability of lifetime alcohol dependence is 40% among adolescents who first tried alcohol as fourteen year old or younger, whereas individual who began drinking at the age of twenty or later has just 10% prevalence rate to become alcoholic.
The cigarette smoking might also affect the drinking prevalence. There is an evidence of co-occurrence of alcohol and cigarette use among adolescents (Hoffman, 2001). Hanna et al (2001) reports that early-onset regular smokers who began at the age of 16 or younger are more likely to use alcohol than non-smokers are. According to Taylor and Conrad (2004), the risk for smoking or using alcohol increases with higher share of smoking friends in adolescent’s environment. Chen and Unger (2002) tested on the sample of 11 239 subjects the hypothesis that cigarette smoking has a gateway effect on alcohol use. The results showed that adolescents who tried the cigarette at least once in their lifetime have higher
6 from Brennan, Walfish (1986) 7 from Slovic (1987) 8 from Saltz and Elandt (1986) 9 risk ratio of last 30-day alcohol use. However, it is not impossible for two drugs to be gateway for each other. Even though the evidence of cigarettes as gateway drug for alcohol is high the causal relationship is ambiguous.
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3 Construction of Model
The main aim of this thesis is to determine which factors influence the alcohol consumption among the high schools students. As many of the studies focus just on one determinant and its causal effect on the adolescent drinking (e.g. Ali and Dwayer, 2010 - social network effects; Engels et al, 2006 - peer group reputation), I have decided to provide a descriptive evidence of youth alcohol consumption9. I try to show which factors are the most significant in the context of all possibly important determinants of adolescent substance use. Since the significance can vary a lot for variable and , I want to compare the results across four different groups (freshmen boys/girls and junior boys/girls).
3.1 Methodology
Since this thesis focuses on the participation indicator of drinking, the dependent variable of interest is binary variable – respondent drank alcohol during last month or did not. The independent variables are categorical and ordinal variables. To deal with the dichotomous explanatory variable, the linear probability model (LPM) is used for the construction. This model (LPM) has its positives as well as its negatives. The main limitation of this model is the natural violation (William, 2009) of ordinary least square (OLS) assumptions, namely the assumption of homoskedasticity, normality and linearity.
Firstly, the violation of the condition of homoskedasticity in the LPM is obvious. As the dependent variable is dummy variable, the residual versus fitted plot looks like two lines, where lay the values of all dependent data. The heteroskedasticity can be eliminated by using heteroskedasticity-robust or cluster-robust estimators for standard errors10(Nichols and Schaffer, 2007). Secondly, errors in the LPM are not normally distributed. However, according to Mittelhammer et al. (2000) for large samples the linear probability converges to normal. Thirdly, it is possible that the values of estimates are higher than 1 or below 0, which advert on the violation of linearity. It is possible to deal with this problem by setting a range (from 0% to 100%) and all the values outside the range are considered to be the
9 The inspiration for this model was the Irish College Study on Behaviour Economics and Drinking Behaviour (Harmon; 2007). Compare to the IZA Paper, the dataset used in this thesis contains different information about individuals and more importantly, the aim of the study is different. While the explanatory variable in Irish College Study are the expenditures on alcohol among college students, my model focus on the probability of high school students to drink alcohol beverages in a short-term period. 10 By using those estimators, just the standard errors term increases but the point estimates stay unchanged. 11 minimum, respectively maximum. On the other hand, the LPM is very intuitive for the construction, where the value of the explanatory variable is a linear combination of the independent variables plus disturbances. It is also easy to interpret.
I could have used the logistic regression for this analysis, which is often used in the social studies (Peng and So, 2002). However, according to Pohlmann and Leitner (2003) and Newman et al. (2004) both methods give very similar results. Even though, logistic regression provides more accurate estimates, there was found a high correlation between estimated effects predicted by OLS and by logistic regression. Therefore, both modelling methods can be used to test model with dichotomous dependent variable. As the aim of this thesis is to distinguish the factors that affect probability of adolescent substance use and the accuracy of estimates is not too important, the linear probability model serves well for my objectives.
3.2 Empirical Model
My model is in its simplif i ed form following: