Journal of Addictive Diseases, 33:210–220, 2014 Copyright Ó Taylor & Francis Group, LLC ISSN: 1055-0887 print / 1545-0848 online DOI: 10.1080/10550887.2014.950023
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE: DATA FROM THE ITALIAN SUBSAMPLE OF THE SECOND INTERNATIONAL SELF-REPORTED DELINQUENCY STUDY Roberto Maniglio, PsyD, PhD1, Marco Innamorati, PsyD2 1 2
Department of History, Society, and Human Studies, University of Salento, Lecce, Italy Department of Human Sciences, European University of Rome, Rome, Italy
To provide a comprehensive picture of the whole spectrum of psychosocial factors potentially associated with adolescent cannabis use, bivariate and multivariate analyses were used to assess a variety of social, demographic, psychological, and behavioral correlates of last-month cannabis use and age of first use among 6,838 students. Results showed that only family problems, alcohol and/or other drug use/misuse, deviant behavior, and victimization were independently associated with either recent cannabis use or early onset of cannabis use when multiple, interacting factors were considered. Certain family and behavioral factors might be more important than other psychosocial correlates of adolescent cannabis use. KEYWORDS. Cannabis use, risk factors, substance use, alcohol abuse, juvenile delinquency, victimization
INTRODUCTION
educational attainment; motor vehicle accidents; accidents at work and home; impaired work performance; use of other illicit drugs; and costs associated with health care, social services, and damage.5–14 Awareness of these negative effects is reflected in the increase in research aimed to know the factors that promote the development and maintenance of cannabis use to develop appropriate prevention and treatment strategies. In particular, a growing number of studies addressing a variety of psychosocial risk factors for adolescent cannabis use have appeared over the past 20 years. These studies have shown that adolescent cannabis use is associated with a large variety of psychosocial factors, such as poor relations with parents, family breakdown, behavioral traits (such as unconventionality, emotionality, high approach, and low avoidance), externalizing problems (such as conduct problems, antisocial or delinquent behavior,
Cannabis is the most common illicit substance used by youths worldwide.1,2 Although trends in cannabis use among youths showed fluctuations over the past twenty years, rates have increased in recent years.1,3 In particular, an increase in the percentage of youths using stronger forms of cannabis at more frequent and heavier levels or at an earlier age has been reported.3,4 These trends are of particular concern because an early onset or heavier levels of use of stronger forms of cannabis may increase the risk of cannabis-related acute and chronic adverse effects. In fact, cannabis use can lead to physical, psychological, academic, work, and social problems, including the following: respiratory, cardiovascular, reproductive, and immunologic problems; neurocognitive impairment; psychiatric symptoms or disorders; lower
Address correspondence to Roberto Maniglio, PsyD, PhD, Department of History, Society, and Human Studies, University of Salento, Via Stampacchia 45/47, 73100 Lecce, Italy. E-mail: [email protected]
210
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE
and aggression), tobacco or alcohol use, parental substance use, and substance use by friends.15–18 However, such a large body of research has not been unanimous in its conclusions. In fact, different studies have suggested different risk factors.17 In addition, there is also considerable controversy on whether some factors (e.g., poor school performance or delinquent behavior) may be the potential causes or effects of cannabis use.10,19 Importantly, most studies have addressed a few, rather than several, psychosocial factors, thus failing to provide a comprehensive picture of the whole wide spectrum of psychological and social variables.11,17 Thus, the theoretical framework for this study is conflicting and fragmentary, given that various conceptual models have focused on different factors that may be potentially associated with adolescent cannabis use. Specifically, although some theoretical models have suggested that cannabis use may be strongly related to family problems,17,18 other models have proposed that cannabis use may be associated with personality factors16 and others have hypothesized a strong link between cannabis use and deviant behavior,19 including the use of other illicit drugs.11,17 Therefore, the current article is aimed at exploring a variety of psychosocial variables (i.e., social and demographic background, use of other drugs, alcohol misuse, traumatic life events, victimization experiences, group behavior, delinquent behavior, and family, school, community, and personality characteristics) that may be associated with adolescent cannabis use to clarify what factors are independently related to cannabis use when multiple, interacting factors are considered. The study hypothesis is that although many psychosocial factors may be related to adolescent cannabis use, only a few of them might be directly associated with adolescent cannabis use. Specifically, it is expected that, when controlling for important social, demographic, psychological, and criminological variables, only adolescents with personality problems, such as low selfcontrol, who experienced family or school problems, used other drugs, and engaged in delinquent behavior (alone or with friends) are
211
more likely to report recent cannabis consumption and an early onset of cannabis use. Despite a large number of studies, there are fundamental questions regarding psychosocial correlates of adolescent cannabis use that remain unanswered. In fact, because most studies have not addressed the whole spectrum of psychological and social variables, the literature on the issue is contradictory and incomplete. Therefore, it is essential to conduct studies aimed at addressing a wide range of psychosocial factors because multiple factors may “cluster” within an individual and interact with each other.20 METHODS Sample Data for this study were drawn from the second International Self-Report Delinquency study (ISRD-2), a cross-national survey aimed at estimating prevalence and correlates of youthful offending and substance use among 67,883 students in 31 countries.21,22 The current analysis is based on the Italian subsample of the dataset consisting of a city-based sample of 6,838 seventh to ninth grade students (paralleling 12- to 15-year-old students) from 15 Italian cities and towns (5 small towns, 6 medium-sized cities, and 4 large cities). Classes (not individual students) were used as primary sampling units. Schools and classes were randomly selected and stratified by school type (academic or vocational) and grade level (7th, 8th, and 9th grade). All students present in each selected class were included in the study if they provided parental consent. Measures All of the dependent and independent variables were measured using the ISRD-2 questionnaire, a structured, self-administered questionnaire containing 67 questions. Participants were asked to fill in the questionnaire during 1 class hour. A researcher was present while the students were filling in the questionnaire to make sure that their answers remained anonymous.
212
Dependent Variables Dependent variables included the use of cannabis in the past month and the age of first use of cannabis. Past month cannabis use was assessed by the participant’s response on whether he or she had used weed, marijuana, or hashish during the past 4 weeks. To ascertain age of first use of cannabis, participants were asked how old they were when they used weed, marijuana, or hashish for the first time. For the purposes of the current study, answers on age of first use of cannabis were collapsed in two mutually exclusive categories: age 12 years or younger abd age 13 years and older. Independent Variables Possible correlates of past month cannabis use and age of first use of cannabis, chosen a priori on the basis of previous research, included sex of the respondent, age at the time of the assessment, parental employment, family structure, family problems, attachment to parents, school performance, school truancy, school environment, neighborhood environment, life events, victimization, self-control and attitudes toward violence, delinquent behavior, deviant group behavior, alcohol misuse, and use of other illicit drugs. Parental employment, family structure, attachment to parents, school performance, school truancy, alcohol misuse, and use of other illicit drugs were assessed according to the participant’s response on whether he or she reported that his or her father or mother had a stable employment; was cohabiting with his or her parents; had a good relationship with his or her father, mother, stepfather, or stepmother; had repeated a school grade; had stayed away from school for at least 1 whole day without a legitimate excuse in the past 12 months; had gotten drunk in his or her lifetime; had used drugs such as ecstasy, speed, LSD, heroin, or cocaine in his or her lifetime. Family problems were assessed using 3 questions exploring parental alcohol or drug problems, marital conflict or violence, and separation or divorce. School environment was assessed using 8 questions exploring the following: (a) the
R. MANIGLIO AND M. INNAMORATI
presence of other activities at school; (b) the occurrence of stealing, fighting, vandalism, or drug use at school; (c) whether the respondent liked his or her school and would miss it if he or she had to move; and (d) whether teachers had noticed when the respondent was doing well. Neighborhood environment was examined using 9 items exploring the following: (a) the presence of crime, fighting, drug selling, abandoned buildings, or graffiti in the neighborhood; and (b) whether people in the neighborhood are close-knit, can be trusted, get along with each other, and are willing to help their neighbors. Negative life events were measured by 6 questions asking whether the respondent had experienced a serious accident or the death or a serious illness of a family member or someone close to him or her. Victimization status was determined using 4 questions assessing whether the respondent had been bullied at school or victim of a criminal offense (robbery/extortion, assault, theft) in the past 12 months. To measure self-control and attitudes toward violence, the ISRD-2 questionnaire used a self-control scale (including four subscales: impulsivity, risk taking, self-centeredness, and volatile temperament23) and a scale of attitudes toward violence.24 Self-control was measured by 12 items exploring whether the respondent does the following: (a) acts on the spur of the moment without stopping to think; (b) does whatever brings his or her pleasure here and now even at the cost of some distant goal; (c) is more concerned with what happens to him or her in the short run than in the long run; (d) likes to test himself or herself every now and then by doing something a little risky; (e) sometimes will take a risk just for the fun of it; (f) agrees that excitement and adventure are more important to him or her than security; (g) tries to look out for himself or herself first even if it means making things difficult for other people; (h) agrees that if things he or she does upset people it’s their problem not his or hers; (i) will try to get the things he or she wants even when he or she knows it’s causing problems for other
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE
people; (j) loses him or her temper pretty easily; (k) agrees that other people better stay away from him or her when he or she is really angry; or (l) agrees that when he or she has a serious disagreement with someone it’s usually hard for him or her to talk calmly about it without getting upset. Positive attitudes toward violence were measured by 5 items asking whether the respondent agrees that (a) a bit of violence is part of the fun; (b) one needs to make use of force to be respected; (c) if one is attacked, one will hit back; (d) without violence everything would be much more boring; and (e) it is completely normal that boys want to prove themselves in physical fights with others. Delinquent behavior was measured by questions about 12 different types of property and violent offences perpetrated by the respondent during the past 12 months (i.e., vandalism, shoplifting, burglary, bike theft, motorbike or car theft, theft from car, snatching, carrying weapon, robbery/extortion, group fight, assault, and drug dealing). Deviant group behavior was measured by 4 items about the kinds of illegal activities the respondent engaged in when he or she hung out with his or her friends in his or her lifetime (i.e., alcohol misuse or drug use, vandalism, shoplifting, and frightening other people). Statistical Analysis Scores for family problems, school environment, neighborhood environment, negative life events, victimization, self-control and attitudes toward violence, delinquent behavior, and deviant group behavior were calculated by means of principal component analyses (PCA). Items assessing each variable were inserted in a series of PCA selecting a one-component solution. Higher scores on each component denote the presence of more problems within the family, at school, or in the neighborhood or the occurrence of more victimization, negative life events, and delinquency. In contrast, lower scores on self-control and attitudes toward violence indicate the presence of more impulsivity, risk taking, self-centeredness, volatile temperament, and positive attitudes toward violence. A series
213
of t-tests and one-way Fisher exact tests were used to assess bivariate differences between groups. Benjamini and Hochberg’s25 correction was used for multiple testing. All variables that were significant after correction for multi-testing were inserted as independent variables in two generalized linear model with groups (past month cannabis use vs. non-cannabis use; firsttime use of cannabis at age 12 years or younger vs. first use at age 13 years and older) as dependent variable. Odds ratios and their 95% confidence intervals (CIs) are reported as measures of association. As indices of model fit, the likelihood ratio x2 test and its P-value were reported. All analyses were performed with SPSS version 19.0 statistical package for the social sciences (IBM, Armonk, NY, USA). Significance level was set at P D 0.05 (two-tailed). RESULTS Characteristics of the Sample Characteristics of the sample are listed in Table 1. Participants had a mean age of 13.95 years (SD D 1.26 years). Of those reporting having used cannabis in their lifetime, nearly half reported having used it in the last month. Factors Associated with Use of Cannabis in the Past Month Differences between youths who used cannabis in the past month and those who did not are highlighted in Table 2. With the exception of TABLE 1. Characteristics of the Sample Variables Female Lifetime cannabis use Last-month cannabis use First-time cannabis use 12 years Living with parents Father with stable job Mother with stable job Attachment to parents Lifetime alcohol misuse 3 times Lifetime use of other drugs Grade retention Last-year school truancy 3 times
N (N D 6838)
%
3560 794 368 118 5725 6295 5285 6706 587 131 680 1064
52.1 11.6 5.4 1.7 83.7 92.1 77.3 98.1 8.6 1.9 9.9 15.6
214
R. MANIGLIO AND M. INNAMORATI
TABLE 2. Factors Associated with Use of Cannabis in the Past Month
Variables Female Age (mean § SD) Living with parents Father with stable job Mother with stable job Attachment to parents Family problems PCA School environment PCA Grade retention Last-year school truancy 3 times Neighborhood environment PCA Life events PCA Last-year victimization PCA Self-control/Attitudes toward violence PCA Lifetime alcohol misuse 3 times Lifetime use of other drugs Last-year delinquent behavior PCA Lifetime deviant group behavior PCA
None (n D 368)
Use of cannabis in the past month (n D 6405)
41.6% 13.88 § 1.25 76.2% 94.7% 76.4% 95.4% 0.43 § 1.36 0.77 § 0.99 29.1% 47.9% 0.62§1.11 0.16 § 1.06 0.30 § 1.40 ¡0.84 § 1.00 53.8% 21.5% 1.63 § 2.54 1.38 § 1.67
52.9% 15.07 § 0.90 84.7% 94.8% 78.8% 98.4% ¡0.03 § 0.97 ¡0.05 § 0.98 8.8% 13.8% ¡0.04§0.98 ¡0.01 § 1.00 ¡0.02 § 0.97 0.05 § 0.98 6.5% 0.8% ¡0.09 § 0.74 ¡0.08 § 0.87
t-test (DF D 6567) 24.05
6.31 15.23
10.70 3.04 4.18 ¡16.20
12.46 16.35
P
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE: DATA FROM THE ITALIAN SUBSAMPLE OF THE SECOND INTERNATIONAL SELF-REPORTED DELINQUENCY STUDY Roberto Maniglio, PsyD, PhD1, Marco Innamorati, PsyD2 1 2
Department of History, Society, and Human Studies, University of Salento, Lecce, Italy Department of Human Sciences, European University of Rome, Rome, Italy
To provide a comprehensive picture of the whole spectrum of psychosocial factors potentially associated with adolescent cannabis use, bivariate and multivariate analyses were used to assess a variety of social, demographic, psychological, and behavioral correlates of last-month cannabis use and age of first use among 6,838 students. Results showed that only family problems, alcohol and/or other drug use/misuse, deviant behavior, and victimization were independently associated with either recent cannabis use or early onset of cannabis use when multiple, interacting factors were considered. Certain family and behavioral factors might be more important than other psychosocial correlates of adolescent cannabis use. KEYWORDS. Cannabis use, risk factors, substance use, alcohol abuse, juvenile delinquency, victimization
INTRODUCTION
educational attainment; motor vehicle accidents; accidents at work and home; impaired work performance; use of other illicit drugs; and costs associated with health care, social services, and damage.5–14 Awareness of these negative effects is reflected in the increase in research aimed to know the factors that promote the development and maintenance of cannabis use to develop appropriate prevention and treatment strategies. In particular, a growing number of studies addressing a variety of psychosocial risk factors for adolescent cannabis use have appeared over the past 20 years. These studies have shown that adolescent cannabis use is associated with a large variety of psychosocial factors, such as poor relations with parents, family breakdown, behavioral traits (such as unconventionality, emotionality, high approach, and low avoidance), externalizing problems (such as conduct problems, antisocial or delinquent behavior,
Cannabis is the most common illicit substance used by youths worldwide.1,2 Although trends in cannabis use among youths showed fluctuations over the past twenty years, rates have increased in recent years.1,3 In particular, an increase in the percentage of youths using stronger forms of cannabis at more frequent and heavier levels or at an earlier age has been reported.3,4 These trends are of particular concern because an early onset or heavier levels of use of stronger forms of cannabis may increase the risk of cannabis-related acute and chronic adverse effects. In fact, cannabis use can lead to physical, psychological, academic, work, and social problems, including the following: respiratory, cardiovascular, reproductive, and immunologic problems; neurocognitive impairment; psychiatric symptoms or disorders; lower
Address correspondence to Roberto Maniglio, PsyD, PhD, Department of History, Society, and Human Studies, University of Salento, Via Stampacchia 45/47, 73100 Lecce, Italy. E-mail: [email protected]
210
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE
and aggression), tobacco or alcohol use, parental substance use, and substance use by friends.15–18 However, such a large body of research has not been unanimous in its conclusions. In fact, different studies have suggested different risk factors.17 In addition, there is also considerable controversy on whether some factors (e.g., poor school performance or delinquent behavior) may be the potential causes or effects of cannabis use.10,19 Importantly, most studies have addressed a few, rather than several, psychosocial factors, thus failing to provide a comprehensive picture of the whole wide spectrum of psychological and social variables.11,17 Thus, the theoretical framework for this study is conflicting and fragmentary, given that various conceptual models have focused on different factors that may be potentially associated with adolescent cannabis use. Specifically, although some theoretical models have suggested that cannabis use may be strongly related to family problems,17,18 other models have proposed that cannabis use may be associated with personality factors16 and others have hypothesized a strong link between cannabis use and deviant behavior,19 including the use of other illicit drugs.11,17 Therefore, the current article is aimed at exploring a variety of psychosocial variables (i.e., social and demographic background, use of other drugs, alcohol misuse, traumatic life events, victimization experiences, group behavior, delinquent behavior, and family, school, community, and personality characteristics) that may be associated with adolescent cannabis use to clarify what factors are independently related to cannabis use when multiple, interacting factors are considered. The study hypothesis is that although many psychosocial factors may be related to adolescent cannabis use, only a few of them might be directly associated with adolescent cannabis use. Specifically, it is expected that, when controlling for important social, demographic, psychological, and criminological variables, only adolescents with personality problems, such as low selfcontrol, who experienced family or school problems, used other drugs, and engaged in delinquent behavior (alone or with friends) are
211
more likely to report recent cannabis consumption and an early onset of cannabis use. Despite a large number of studies, there are fundamental questions regarding psychosocial correlates of adolescent cannabis use that remain unanswered. In fact, because most studies have not addressed the whole spectrum of psychological and social variables, the literature on the issue is contradictory and incomplete. Therefore, it is essential to conduct studies aimed at addressing a wide range of psychosocial factors because multiple factors may “cluster” within an individual and interact with each other.20 METHODS Sample Data for this study were drawn from the second International Self-Report Delinquency study (ISRD-2), a cross-national survey aimed at estimating prevalence and correlates of youthful offending and substance use among 67,883 students in 31 countries.21,22 The current analysis is based on the Italian subsample of the dataset consisting of a city-based sample of 6,838 seventh to ninth grade students (paralleling 12- to 15-year-old students) from 15 Italian cities and towns (5 small towns, 6 medium-sized cities, and 4 large cities). Classes (not individual students) were used as primary sampling units. Schools and classes were randomly selected and stratified by school type (academic or vocational) and grade level (7th, 8th, and 9th grade). All students present in each selected class were included in the study if they provided parental consent. Measures All of the dependent and independent variables were measured using the ISRD-2 questionnaire, a structured, self-administered questionnaire containing 67 questions. Participants were asked to fill in the questionnaire during 1 class hour. A researcher was present while the students were filling in the questionnaire to make sure that their answers remained anonymous.
212
Dependent Variables Dependent variables included the use of cannabis in the past month and the age of first use of cannabis. Past month cannabis use was assessed by the participant’s response on whether he or she had used weed, marijuana, or hashish during the past 4 weeks. To ascertain age of first use of cannabis, participants were asked how old they were when they used weed, marijuana, or hashish for the first time. For the purposes of the current study, answers on age of first use of cannabis were collapsed in two mutually exclusive categories: age 12 years or younger abd age 13 years and older. Independent Variables Possible correlates of past month cannabis use and age of first use of cannabis, chosen a priori on the basis of previous research, included sex of the respondent, age at the time of the assessment, parental employment, family structure, family problems, attachment to parents, school performance, school truancy, school environment, neighborhood environment, life events, victimization, self-control and attitudes toward violence, delinquent behavior, deviant group behavior, alcohol misuse, and use of other illicit drugs. Parental employment, family structure, attachment to parents, school performance, school truancy, alcohol misuse, and use of other illicit drugs were assessed according to the participant’s response on whether he or she reported that his or her father or mother had a stable employment; was cohabiting with his or her parents; had a good relationship with his or her father, mother, stepfather, or stepmother; had repeated a school grade; had stayed away from school for at least 1 whole day without a legitimate excuse in the past 12 months; had gotten drunk in his or her lifetime; had used drugs such as ecstasy, speed, LSD, heroin, or cocaine in his or her lifetime. Family problems were assessed using 3 questions exploring parental alcohol or drug problems, marital conflict or violence, and separation or divorce. School environment was assessed using 8 questions exploring the following: (a) the
R. MANIGLIO AND M. INNAMORATI
presence of other activities at school; (b) the occurrence of stealing, fighting, vandalism, or drug use at school; (c) whether the respondent liked his or her school and would miss it if he or she had to move; and (d) whether teachers had noticed when the respondent was doing well. Neighborhood environment was examined using 9 items exploring the following: (a) the presence of crime, fighting, drug selling, abandoned buildings, or graffiti in the neighborhood; and (b) whether people in the neighborhood are close-knit, can be trusted, get along with each other, and are willing to help their neighbors. Negative life events were measured by 6 questions asking whether the respondent had experienced a serious accident or the death or a serious illness of a family member or someone close to him or her. Victimization status was determined using 4 questions assessing whether the respondent had been bullied at school or victim of a criminal offense (robbery/extortion, assault, theft) in the past 12 months. To measure self-control and attitudes toward violence, the ISRD-2 questionnaire used a self-control scale (including four subscales: impulsivity, risk taking, self-centeredness, and volatile temperament23) and a scale of attitudes toward violence.24 Self-control was measured by 12 items exploring whether the respondent does the following: (a) acts on the spur of the moment without stopping to think; (b) does whatever brings his or her pleasure here and now even at the cost of some distant goal; (c) is more concerned with what happens to him or her in the short run than in the long run; (d) likes to test himself or herself every now and then by doing something a little risky; (e) sometimes will take a risk just for the fun of it; (f) agrees that excitement and adventure are more important to him or her than security; (g) tries to look out for himself or herself first even if it means making things difficult for other people; (h) agrees that if things he or she does upset people it’s their problem not his or hers; (i) will try to get the things he or she wants even when he or she knows it’s causing problems for other
PSYCHOSOCIAL CORRELATES OF ADOLESCENT CANNABIS USE
people; (j) loses him or her temper pretty easily; (k) agrees that other people better stay away from him or her when he or she is really angry; or (l) agrees that when he or she has a serious disagreement with someone it’s usually hard for him or her to talk calmly about it without getting upset. Positive attitudes toward violence were measured by 5 items asking whether the respondent agrees that (a) a bit of violence is part of the fun; (b) one needs to make use of force to be respected; (c) if one is attacked, one will hit back; (d) without violence everything would be much more boring; and (e) it is completely normal that boys want to prove themselves in physical fights with others. Delinquent behavior was measured by questions about 12 different types of property and violent offences perpetrated by the respondent during the past 12 months (i.e., vandalism, shoplifting, burglary, bike theft, motorbike or car theft, theft from car, snatching, carrying weapon, robbery/extortion, group fight, assault, and drug dealing). Deviant group behavior was measured by 4 items about the kinds of illegal activities the respondent engaged in when he or she hung out with his or her friends in his or her lifetime (i.e., alcohol misuse or drug use, vandalism, shoplifting, and frightening other people). Statistical Analysis Scores for family problems, school environment, neighborhood environment, negative life events, victimization, self-control and attitudes toward violence, delinquent behavior, and deviant group behavior were calculated by means of principal component analyses (PCA). Items assessing each variable were inserted in a series of PCA selecting a one-component solution. Higher scores on each component denote the presence of more problems within the family, at school, or in the neighborhood or the occurrence of more victimization, negative life events, and delinquency. In contrast, lower scores on self-control and attitudes toward violence indicate the presence of more impulsivity, risk taking, self-centeredness, volatile temperament, and positive attitudes toward violence. A series
213
of t-tests and one-way Fisher exact tests were used to assess bivariate differences between groups. Benjamini and Hochberg’s25 correction was used for multiple testing. All variables that were significant after correction for multi-testing were inserted as independent variables in two generalized linear model with groups (past month cannabis use vs. non-cannabis use; firsttime use of cannabis at age 12 years or younger vs. first use at age 13 years and older) as dependent variable. Odds ratios and their 95% confidence intervals (CIs) are reported as measures of association. As indices of model fit, the likelihood ratio x2 test and its P-value were reported. All analyses were performed with SPSS version 19.0 statistical package for the social sciences (IBM, Armonk, NY, USA). Significance level was set at P D 0.05 (two-tailed). RESULTS Characteristics of the Sample Characteristics of the sample are listed in Table 1. Participants had a mean age of 13.95 years (SD D 1.26 years). Of those reporting having used cannabis in their lifetime, nearly half reported having used it in the last month. Factors Associated with Use of Cannabis in the Past Month Differences between youths who used cannabis in the past month and those who did not are highlighted in Table 2. With the exception of TABLE 1. Characteristics of the Sample Variables Female Lifetime cannabis use Last-month cannabis use First-time cannabis use 12 years Living with parents Father with stable job Mother with stable job Attachment to parents Lifetime alcohol misuse 3 times Lifetime use of other drugs Grade retention Last-year school truancy 3 times
N (N D 6838)
%
3560 794 368 118 5725 6295 5285 6706 587 131 680 1064
52.1 11.6 5.4 1.7 83.7 92.1 77.3 98.1 8.6 1.9 9.9 15.6
214
R. MANIGLIO AND M. INNAMORATI
TABLE 2. Factors Associated with Use of Cannabis in the Past Month
Variables Female Age (mean § SD) Living with parents Father with stable job Mother with stable job Attachment to parents Family problems PCA School environment PCA Grade retention Last-year school truancy 3 times Neighborhood environment PCA Life events PCA Last-year victimization PCA Self-control/Attitudes toward violence PCA Lifetime alcohol misuse 3 times Lifetime use of other drugs Last-year delinquent behavior PCA Lifetime deviant group behavior PCA
None (n D 368)
Use of cannabis in the past month (n D 6405)
41.6% 13.88 § 1.25 76.2% 94.7% 76.4% 95.4% 0.43 § 1.36 0.77 § 0.99 29.1% 47.9% 0.62§1.11 0.16 § 1.06 0.30 § 1.40 ¡0.84 § 1.00 53.8% 21.5% 1.63 § 2.54 1.38 § 1.67
52.9% 15.07 § 0.90 84.7% 94.8% 78.8% 98.4% ¡0.03 § 0.97 ¡0.05 § 0.98 8.8% 13.8% ¡0.04§0.98 ¡0.01 § 1.00 ¡0.02 § 0.97 0.05 § 0.98 6.5% 0.8% ¡0.09 § 0.74 ¡0.08 § 0.87
t-test (DF D 6567) 24.05
6.31 15.23
10.70 3.04 4.18 ¡16.20
12.46 16.35
P
