Violent behaviour among adolescents in Iceland: a national survey

Gerdur Run Gudlaugsdottir1, Runar Vilhjalmsson2, Gudrun Kristjansdottir2, Rune Jacobsen3 and Dan Meyrowitsch3

1 Gerdur Run Gudlaugsdottir, Master of Public Health Programme, Institute of Public Health, University of Copenhagen, Denmark
2 Faculty of Nursing, University of Iceland, Iceland
3 Department of Epidemiology, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark

Correspondence: Runar Vilhjalmsson, Faculty of Nursing, University of Iceland, Eirbergi, Eiriksgotu 34, IS-101 Reykjavik, Iceland. E-mail: runarv{at}hi.is


    Abstract
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 Abstract
 Methods
 Results
 Discussion
 Conclusion
 References
 
Background Violence among adolescents may have serious developmental, physical, and mental health consequences for the affected individuals. In this study, we assessed the prevalence of violent behaviour and its correlates among 15–16 year old schoolchildren in Iceland.

Methods In 1997, a cross-sectional survey was conducted among a random half of all Icelandic schoolchildren aged 15–16 years. The overall response rate was 91% (N = 3872). In the present study, socio-demographic background, social support, negative life events, psychological distress, and substance use were considered in relation to violent behaviour using logistic regression techniques.

Results The majority of the respondents reported having committed violence within the last year. Boys were more likely to use violence than girls (odds ratio [OR] = 5.6; 95% CI: 4.7, 6.6). Respondents who had experienced ≥4 negative life events in the past year were more likely to use violence than respondents with no negative life events (OR = 3.0; 95% CI: 2.2, 4.2). Smokers were more likely than non-smokers to use violence (OR = 1.7; 95% CI: 1.2, 2.2), and adolescents who had used alcohol >20x in their lifetime were more than twice as likely to commit violence compared with those who had never used alcohol (OR = 2.5; 95% CI: 1.8, 3.4).

Conclusion Rates of violent behaviour among Icelandic schoolchildren were high. Gender, parental support, life stress, anger/aggression, and substance use were all significantly related to the perpetration of violent acts.


Keywords Violence, adolescents, perpetrators, risk factors, schoolchildren

Accepted 1 March 2004

Violence committed by young people is one the most visible forms of deviance in Western societies as evidenced by daily media reports. Concerns about youth violence have increased steadily over the past decades and efforts to identify risk and protective factors have been intensified.1

A growing number of studies on adolescents suggests that violent behaviour or the intention to use violence is associated with a number of contextual, individual, and situational factors.2–5 Some studies report age or grade effects, suggesting that older adolescents are more likely to commit violence than their younger counterparts.6 Almost all studies agree that boys are more likely than girls to engage in violent behaviour.1–2,714 The gender effect generally persists after adjusting for confounding variables. Low parental education and income are sometimes associated with adolescent violence, but tend to be non-significant after adjustment for confounding.15 Likewise, there is some evidence that religious belief is inversely related to adolescent violence, but the relationship may not hold after adjustment for confounding.15 Low parental support appears to be an important predictor of adolescent violence.10,1516 There is also limited evidence that strong peer support may increase risk of violence.15 The experience of negative life events, ranging from academic failure to parental divorce, also appears to foster violent and other maladaptive behaviour in children and adolescents.1,12,15,17 Ellickson and McGuigan found that poor grades at the age of 13 predicted violent behaviour 5 years later.12 They also found that parental death, separation/divorce, and job loss were all related to adolescent violence. Other adolescent studies have found associations between psychological distress and violent activity. Song and colleagues found that anger was the most important form of psychological distress related to violent behaviours for both genders.18 Substance use has also been related to violent activity.6–7,15 According to Ellickson and colleagues, violent adolescents are much more likely to be regular users of alcohol, cigarettes, or marijuana, or be poly-drug users.7 Other studies have also confirmed that the availability of drugs increases the risk for violence.1

The purpose of this study was to establish the prevalence of violent behaviour in the general population of Icelandic mid-adolescents, and its relationship to personal, situational, and demographic factors assumed or found to be related to such behaviour in previous work. Icelandic society is frequently said to be characterized by cultural homogeneity and social/economic equality,19,20 although differences between population groups are usually larger than such notions assume.21,22 Icelanders tend to emphasize the values of individual freedom and socio-economic equality, and their work ethic is characteristically strong.23,24 Not surprisingly, labour market participation is exceptionally high, both among men and women.25 As a consequence, concerns have been raised that many Icelandic parents spend too little time with their children, which may undermine parental monitoring and support, rendering the kids vulnerable to distress and risk behaviours, including violence.26,27 Recent years have seen considerable media discussion in Iceland about an alleged increase in violence in general, and among young people in particular. Furthermore, surveys find that the public is increasingly concerned about the issue.28 Such concerns may reflect increased news reporting or police involvement as much as changes in rates of violence. Few investigations in Iceland have addressed the scope and correlates of violent behaviours. Available adolescent studies have found associations between violence and substance use, academic problems, and parental support,29,30 all of which have been identified as correlates in previous, mostly US studies.

The many converging results across studies on adolescent violence may seem surprising given that the literature is methodologically diverse, focuses on different correlates, uses different definitions of violence, and often pertains to specialized populations.31 Consistent with a WHO definition,14 the present study defined violence as the intentional use of physical force or power, threatened or actual, against another person, that has a high likelihood of resulting in physical or psychological harm. This definition covers all types of violence, including a range of acts that do not necessarily result in injuries or death.


    Methods
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 Methods
 Results
 Discussion
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 References
 
The study was based on data from a nationwide Icelandic cross-sectional survey of older schoolchildren, titled Young People '97.32 The survey included the entire population of Icelandic children in grades 9 and 10 (age 15 and 16) in all primary schools in the country (schooling is obligatory for all children through the 10th grade). Two versions of the survey questionnaire were administered—version A with an emphasis on issues of substance use and health, and version B emphasizing issues of violence and deviance. A random half of students in each school answered each version of the questionnaire. This study uses data from the 50% of students answering version B of the questionnaire. Subjects filled out the questionnaire anonymously during regular school hours. Central parts of the questionnaire had been pre-tested in earlier Young People surveys.33 Valid version B questionnaires were received from 3872 subjects, resulting in a response of 91%.32 Of the respondents, 51% were male, and 52% resided in Reykjavik, the capital of Iceland.

Measures
Sixteen independent variables, identified in previous work on adolescent violence, were included in the analysis. Sociodemographic background comprised grade (9th versus 10th), gender, residence (urban, densely populated area, rural area, farm), religion (Lutheran, Pentecostal, Roman Catholic, other denomination, no denomination), and father's and mother's educational level (each coded 1 = primary school, 2 = started gymnasium/vocational education, 3 = finished gymnasium/vocational education, 4 = started university level education, 5 = finished university level education). Social support from parents and friends were summary scales based on items developed in previous work on social support by Vilhjalmsson.34–36 Respondents were asked eight questions about how easy or difficult is was for them to receive warmth and care, discuss personal matters, get advice about their school work, get advice about other tasks, get assistance with various tasks, get other assistance, borrow money, or borrow things, such as equipment or clothes. Each set of questions was assessed separately for parents and friends. Four-point parental and friend support indices were finally created (coded as 1 = very difficult to get support, 2 = rather difficult, 3 = rather easy, 4 = very easy). (Chronbach's alphas for parental and friend support were 0.84 and 0.86, respectively). Negative life events in past 12 months included 14 events, e.g. serious accident, parental divorce, death of a parent or sibling, expulsion from school, and getting poor grades. The 14 items were summed and a new variable created. This new variable (number of negative life events) was truncated at ≥4 events, due to the limited number of cases beyond that level. Anxiety was a two-item summary scale, asking respondents how often they had been nervous, and tense or aggravated during the past week (each coded from 0 = never to 3 = often) (Chronbach's alpha = 0.76). Depression was a summary scale adapted from Pearlin and Lieberman37 including 10 items (symptoms). Respondents were asked how often they had experienced each symptom during the past week, e.g. lacking enthusiasm for doing anything, feeling lonely, crying easily or feeling like crying, and feeling hopeless about the future (each coded from 0 = never to 3 = often) (Chronbach's alpha = 0.86). Anger/aggression was a five-item summary scale adapted from the hostility subscale of the SCL-90 symptom checklist,38 asking respondents how often during the past week they had bursts of anger that could not be controlled, wanted to break or smash things, got in a fight, shouted and threw things, and were easily angered or irritated (each coded from 0 = never to 3 = often) (Chronbach's alpha = 0.84 ). Following other authors,35,39 high psychological distress was defined as the upper 20% of distress scores. Hence, dichotomized measures were created separating high from medium or low scores for anxiety (<4 versus ≥4), depression (<12 versus ≥12), and anger/aggression (<6 versus >6). Substance use included three behaviours—smoking, drinking, and hashish use. Respondents were asked how often during their lifetime they had smoked cigarettes, consumed alcoholic beverages, been drunk (intoxicated), and used hashish (seven categories from ‘never’ to ‘≥40x’). Due to a small number of cases, some substance use categories were collapsed to form scales of lifetime cigarette smoking (never; 1–2x; 3–39x; ≥ 40x), lifetime alcohol consumption (never, 1–5x; 6–19x; ≥20x); total number of times drunk (never, 1–2x; 3–9x; ≥10x), and lifetime hashish use (never; 1–2x; ≥3x).

The dependent variable—violent behaviour—was based on seven questions about involvement in violent acts. Respondents were asked how often in the past 12 months they had punched, kicked, or struck someone, grabbed another person by the throat, head-butted someone, threatened someone with violence, or threatened another person with a weapon. When considering the correlates of violence, the study focuses on the odds of committing violence using a dichotomous measure indicating whether or not any violent act had been committed in the past 12 months.

Statistical analysis
Logistic regression was used to assess gross and net effects of each explanatory variable on violent behaviour. First, bivariate associations between violent behaviour and explanatory variables were assessed. Subsequently, significant variables at the bivariate level (n = 11) were entered into a stepwise backward selection to identify a subset of significant net predictors. At each stage, the least important variable (the one with the highest non-significant P-value) was excluded. This procedure resulted in six predictive variables showing statistical significance (P < 0.05). The set of six explanatory variables was entered into a multiple regression analysis resulting in one model for overall violence. This procedure allowed for the evaluation of the importance of one specific predictive variable, while controlling for the effects of the five remaining confounding variables. Interaction effects between gender and the other explanatory variables were additionally examined. All analyses used the SAS software package, version 8.2.


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 Methods
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The prevalence of violent acts among Icelandic adolescents
Among the 3726 respondents, 58.9% had utilized one or more of the seven violent acts at least once in the past year. Table 1 shows the prevalence of the seven violent acts. Kicking was the most common act, followed by striking and punching. The least frequent violent act was threatening with a weapon (<4%). The vast majority of perpetrators had committed violent acts ≤5x during the past 12 months.


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Table 1 The prevalence of the seven violent acts in the past year (all respondents)

 
Factors related to the probability of committing violence
Table 2 shows the results of the bivariate and multivariate analyses. Eleven significant independent variables were identified in the bivariate analysis. Five variables—grade, residence, mother's education, father's education, and anxiety—were not significantly related to violent behaviour. Among the sociodemographic variables, only gender and religion resulted in a significant effect. Boys were more likely than girls to engage in violent behaviour, and adolescents who did not belong to a religious denomination were more likely than others to commit violence.


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Table 2 Odds ratios (OR) for committing violence among Icelandic 15–16 year-old Icelandic schoolchildren, by significant independent variables

 
The multivariate analysis identified six significant independent variables, i.e. gender, social support from parents, negative life events, anger/aggression, smoking, and alcohol use. Boys were 5.5x (95% CI: 4.7, 6.6) more likely than girls to use violence. Adolescents who reported that it was rather difficult to get support from their parents were 68% more likely to use violence than those who said it was very easy. As the number of negative life events increased so did the likelihood of committing violence. Those who had experienced ≥4 negative life events in the past year were 3x (95% CI: 2.2, 4.2) more likely to use violence than those who had not experienced any of the events. Adolescents categorized as highly angry/aggressive were more likely to use violence and also children who had repeatedly smoked cigarettes and used alcohol during their lifetime. The latter variable had a large effect: Those who had consumed alcohol ≥20x were 2.5x (95% CI: 1.8, 3.4) more likely to commit violence than those who had never used alcohol. No interaction with gender was statistically significant.


    Discussion
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 Abstract
 Methods
 Results
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The results of the present study revealed high prevalence of violent behaviour among mid-adolescent Icelandic schoolchildren. Nearly 60% had committed at least one violent act in the preceding year. Three independent variables—gender, negative life events, and alcohol consumption—had the strongest relationships with violent behaviour. Smoking and high levels of anger/aggression were also substantially related to violent behaviour. Lastly, social support from parents was significantly related to violent behaviour. After adjustment for confounding there were no net relationships with grade, residence, religion, parental education, social support from friends, anxiety, depression, number of times drunk, or the use of hashish.

The non-significant effect of grade runs counter to some previous research,6 which may perhaps be explained by the limited age variation in this sample of 9th and 10th graders. However, the results from the present study are in agreement with other empirical work finding more extensive violence among boys than girls.1,2,7–14 The gender effect cannot be explained by differences between boys and girls in negative life events, social supports, or substance use, because gender remained an important correlate of violence net of these and other (demographic) variables. The precise meaning of the gender effect is an important research topic that deserves further analysis in future research. The inverse relationship between parental support and adolescent violence is consistent with other studies.10,15,16 However, friend support was unrelated to violence when other variables were controlled. This and other studies of social support effects in adolescence40 suggest that parents rather than peers are the key support source preventing deviance and promoting health in adolescence. Furthermore, the relationship between negative life events and violence is in line with other adolescent studies finding relationships between violence and school-related negative events.1,12,15 A closer look at individual life events (analysis not shown) revealed that poor grades, expulsion from school, physical conflicts at home, and serious arguments at home were the most important events associated with violent behaviour. The study found anger/aggression to be the primary form of distress related to violent acts, consistent with results presented by Song and colleagues.18 This does not necessarily mean that anger/aggression causes violence, since both measures may reflect the same underlying construct. Both smoking and alcohol consumption were strongly associated with violent behaviour and these findings are supported by previous observations.31 However, the causal mechanism is unclear, as these associations may be partly explained by extraneous confounding variables not included in this study, e.g. pertaining to peer group lifestyles or cultures. The non-significant effect of hashish seems to be in agreement with some studies,9 but not others.6 In short, our findings generally agree with results from previous, mostly US, adolescent studies, providing further cross-cultural support for the identified relationships between personal, situational and demographic variables and violent behaviour in this age group.

Strengths and weaknesses of the study
The main strengths of the study include a pre-tested questionnaire, exceptionally high response rate, large sample size, coverage of an entire cohort within a country, and a well-established definition of violence. Hence, the results can be generalized to Icelanders in mid-adolescence with considerable confidence. Although questions of sensitive and undesirable phenomena, such as violent behaviour, may risk underreporting, adolescents tend to be reasonably truthful when reporting their own problem behaviours.41 Furthermore, anonymity should generally encourage truthful reporting in such instances.42

Several limitations of the study should be noted. Firstly, the cross-sectional nature of the study precludes firm causal interpretation of the results. Thus, distress may affect violent behaviour, violent behaviour may result in distress, or both. Likewise, substance use may be the cause or consequence of violent behaviour. Secondly, recall bias may have affected reporting of violent behaviour and substance use, which spanned a 12-month period prior to the survey. Thirdly, the study did not provide information on all potential or likely risk factors, such as self-esteem, violent behaviour of friends or parents, own prior victimization, and the use of hard drugs. Future research should focus on a broader spectrum of predictors over time in order to identify causal determinants of violence in this population.


    Conclusion
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In summary, the study found that male gender, low parental support, negative live events such as school failures and family misadventures, anger/aggression, and substance use were all related to involvement in violent behaviour in mid-adolescence. The study suggests that efforts to curb violence in this age group need to take both the school and family environment, as well as risk behaviours (smoking and alcohol consumption) into account. Such efforts should not only involve student health education focusing on violence-related health risks, but should also involve effective co-operation and partnership between teachers, principals, and parents, aimed at providing the student a safer and more secure social environment.


KEY MESSAGES

  • This study revealed a high prevalence of violent behaviour among mid-adolescent Icelandic schoolchildren.
  • Male gender, negative life events, and alcohol use had the strongest relationships with violent behaviour.
  • Low parental support, smoking, and high levels of anger/aggression were also substantially related to violent behaviour

 


    Acknowledgments
 
Karin Helweg-Larsen, National Institute of Public Health is acknowledged for her contribution to this study. We would also like to thank Sian Jones for her helpful comments to the manuscript. Per Kragh Andersen, Institute for Public Health, University of Copenhagen is thanked for his helpful advice with the statistics.


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