Is cannabis a gateway drug? Testing hypotheses about the relationship between cannabis use and the use of other illicit drugs

We outline and evaluate competing explanations of three relationships that have consistently been found between cannabis use and the use of other illicit drugs, namely, ( 1) that cannabis use typically precedes the use of other illicit drugs; and that ( 2) the earlier cannabis is used, and ( 3) the more regularly it is used, the more likely a young person is to use other illicit drugs. We consider three major competing explanations of these patterns: ( 1) that the relationship is due to the fact that there is a shared illicit market for cannabis and other drugs which makes it more likely that other illicit drugs will be used if cannabis is used; ( 2) that they are explained by the characteristics of those who use cannabis; and ( 3) that they reflect a causal relationship in which the pharmacological effects of cannabis on brain function increase the likelihood of using other illicit drugs. These explanations are evaluated in the light of evidence from longitudinal epidemiological studies, simulation studies, discordant twin studies and animal studies. The available evidence indicates that the association reflects in part but is not wholly explained by: ( 1) the selective recruitment to heavy cannabis use of persons with pre-existing traits ( that may be in part genetic) that predispose to the use of a variety of different drugs; ( 2) the affiliation of cannabis users with drug using peers in settings that provide more opportunities to use other illicit drugs at an earlier age; ( 3) supported by socialisation into an illicit drug subculture with favourable attitudes towards the use of other illicit drugs. Animal studies have raised the possibility that regular cannabis use may have pharmacological effects on brain function that increase the likelihood of using other drugs. We conclude with suggestions for the type of research studies that will enable a decision to be made about the relative contributions that social context, individual characteristics, and drug effects make to the relationship between cannabis use and the use of other drugs.

Acute alcohol consumption and mechanism of injury

Objective: The purpose of this study was to determine whether injury mechanism among injured patients is differentially distributed as a function of acute alcohol consumption (quantity, type, and drinking setting). Method: A cross-sectional study was conducted between October 2000 and October 2001 in the Gold Coast Hospital Emergency Department, Queensland, Australia. Data were collected quarterly over a 12-month period. Every injured patient who presented to the emergency department during the study period for treatment of an injury sustained less than 24 hours prior to presentation was approached for interview. The final sample comprised 593 injured patients (males = 377). Three measures of alcohol consumption in the 6 hours prior to injury were obtained from self-report: quantity, beverage type, and drinking setting. The main outcome measure was mechanism of injury which was categorized into six groups: road traffic crash (RTC), being hit by or against something, fall, cut/piercing, overdose/poisoning, and miscellaneous. Injury intent was also measured (intentional vs unintentional). Results: After controlling for relevant confounding variables, neither quantity nor type of alcohol was significantly associated with injury mechanism. However, drinking setting (i.e., licensed premise) was significantly associated with increased odds of sustaining an intentional versus unintentional injury (odds ratio [OR] = 2.79, 95% confidence interval [CI] = 1.4-5.6); injury through being hit by/against something versus other injury types (OR = 2.59, 95% CI = 1.4-4.9); and reduced odds of sustaining an injury through RTC versus non-RTC (OR = 0.02, 95% CI = 0.004-0.9), compared with not drinking alcohol prior to injury. Conclusions: No previous analytical studies have examined the relationship between injury mechanism and acute alcohol consumption (quantity, type, and setting) across all types of injury and all injury severities while controlling for potentially important confounders (demographic and situational confounders, risk-taking behavior, substance use, and usual drinking patterns). These data suggest that among injured patients, mechanism of injury is not differentially distributed as a function of quantity or type of acute alcohol consumption but may be differentially distributed as a function of drinking setting (i.e., RTC, intentional injury, being hit). Therefore, prevention strategies that focus primarily on the quantity and type of alcohol consumed should be directed generically across injury mechanisms and not limited to particular cause of injury campaigns.

Alcohol use and risk taking among regular ecstasy users

We examine alcohol use in conjunction with ecstasy use and risk-taking behaviors among regular ecstasy users in every capital city in Australia. Data on drug use and risks were collected in 2004 from a national sample of 852 regular ecstasy users (persons who had used ecstasy at least monthly in the preceding 6 months). Users were grouped according to their typical alcohol use when using ecstasy: no use, consumption of between one and five standard drinks, and consumption of more than five drinks (binge alcohol use). The sample was young, well educated, and mainly working or studying. Approximately two thirds (65%) of the regular ecstasy users reported drinking alcohol when taking ecstasy. Of these, 69% reported usually consuming more than five standard drinks. Those who did not drink alcohol were more disadvantaged, with greater levels of unemployment, less education, higher rates of drug user treatment, and prison history. They were also more likely than those who drank alcohol when using ecstasy to be drug injectors and to be hepatitis C positive. Excluding alcohol, drug use patterns were similar between groups, although the no alcohol group used cannabis and methamphetamine more frequently. Binge drinkers were more likely to report having had three or more sexual partners in the past 6 months and were less likely to report having safe sex with casual partners while under the influence of drugs. Despite some evidence that the no alcohol group were more entrenched drug users, those who typically drank alcohol when taking ecstasy were as likely to report risks and problems associated with their drug use. It appears that regular ecstasy users who binge drink are placing themselves at increased sexual risk when under the influence of drugs. Safe sex messages should address the sexual risk associated with substance use and should be tailored to reducing alcohol consumption, particularly targeting heavy alcohol users. The study's limitations are noted.

Is cannabis use a contributory cause of psychosis?

Objective: To assess whether cannabis use in adolescence and young adulthood is a contributory cause of schizophreniform psychosis in that it may precipitate psychosis in vulnerable individuals. Method: We reviewed longitudinal studies of adolescents and young adults that examined the relations between self-reported cannabis use and the risk of diagnosis with a psychosis or of reporting psychotic symptoms. We also reviewed studies that controlled for potential confounders, such as other forms of drug use and personal characteristics that predict an increased risk of psychosis. We assessed evidence for the biological plausibility of a contributory causal relation. Results: Evidence from 6 longitudinal studies in 5 countries shows that regular cannabis use predicts an increased risk of a schizophrenia diagnosis or of reporting symptoms of psychosis. These relations persisted after controlling for confounding variables, such as personal characteristics and other drug use. The relation did not seem to be a result of cannabis use to self-medicate symptoms of psychosis. A contributory causal relation is biologically plausible because psychotic disorders involve disturbances in the dopamine neurotransmitter systems with which the cannabinoid system interacts, as demonstrated by animal studies and one human provocation study. Conclusion: It is most plausible that cannabis use precipitates schizophrenia in individuals who are vulnerable because of a personal or family history of schizophrenia.

The mental health risks of adolescent cannabis use

Since the early 1970s, when cannabis first began to be widely used [1], the proportion of young people who have used cannabis has steeply increased and the age of first use has declined [2, 3]. Most cannabis users now start in the mid-to-late teens [1], an important period of psychosocial transition when misadventures can have large adverse effects on a young person's life chances.

ANSIEDADE E CONSUMO DE SUBSTÂNCIAS PSICOATIVAS EM ADOLESCENTES

Os objetivos deste estudo foram: relacionar o consumo de substâncias psicoativas e ansiedade, verificar os níveis de ansiedade e as substâncias psicoativas mais consumidas, e associar consumo de substâncias psicoativas e ansiedade entre estudantes do ensino médio de escolas públicas e particulares da cidade de Maceió. Os estudantes e as instituições que participaram da pesquisa foram selecionados por meio de amostragem não-probabilística por conveniência. Tratou-se de um estudo de delineamento correlacional. A amostra foi de 407 estudantes, com idade de 14 a 18 anos. A pesquisa foi realizada em sete escolas, sendo quatro da rede pública estadual e três da rede particular. Os participantes responderam a um questionário sóciodemográfico; à Escala de Ansiedade do Adolescente (EAA); e a um questionário sobre o consumo de substâncias psicoativas. Foi feita a análise das relações entre consumo de substâncias psicoativas e ansiedade por meio do teste qui-quadrado e exato de Fisher. O álcool foi a substância lícita mais consumida pelos estudantes, enquanto o solvente, a substância ilícita mais consumida por esse grupo. Os participantes apresentaram maior percentual no nível moderado: 28%. Verificou-se diferença estatisticamente significativa entre o consumo de substâncias psicoativas e ansiedade nos adolescentes. O uso na vida de solventes (p=0,037) e energéticos (p=0,023); uso no ano de cigarro (p=0,043) e bebidas alcoólicas (p=0,007); e uso freqüente de bebidas alcoólicas (p<0,001) relacionou-se com ansiedade moderada. Houve diferença significativa entre consumo de substâncias psicoativas e ansiedade nos tipos de escola: Na escola pública, houve relação entre estudantes que disseram consumir cigarro na vida e no ano, e entre os que fizeram uso na vida de solventes e energéticos com ansiedade grave (p=0,022; p=0,003; p=0,010;p=0=0,44, respectivamente); e entre estudantes que afirmaram ter feito consumo freqüente de bebidas alcoólicas com ansiedade moderada (p=0,007). Na escola particular, houve relação entre estudantes consumiram bebidas alcoólicas no ano com ansiedade moderada (p=0,011). A pesquisa verificou a necessidade de se realizarem projetos de prevenção de drogas e promoção de saúde que visem aumentar a reflexão sobre o estilo de vida e ansiedade.

Prefrontal cortical and striatal activity to happy and fear faces in bipolar disorder is associated with comorbid substance abuse and eating disorder

Background: The spectrum approach was used to examine contributions of comorbid symptom dimensions of substance abuse and eating disorder to abnormal prefrontal-cortical and subcortical-striatal activity to happy and fear faces previously demonstrated in bipolar disorder (BD). Method: Fourteen remitted BD-type I and sixteen healthy individuals viewed neutral, mild and intense happy and fear faces in two event-related fMRI experiments. All individuals completed Substance-Use and Eating-Disorder Spectrum measures. Region-of-Interest analyses for bilateral prefrontal and subcortical-striatal regions were performed. Results: BD individuals scored significantly higher on these spectrum measures than healthy individuals (p < 0.05), and were distinguished by activity in prefrontal and subcortical-striatal regions. BD relative to healthy individuals showed reduced dorsal prefrontal-cortical activity to all faces. Only BD individuals showed greater subcortical-striatal activity to happy and neutral faces. In BD individuals, negative correlations were shown between substance use severity and right PFC activity to intense happy faces (p < 0.04), and between substance use severity and right caudate nucleus activity to neutral faces (p < 0.03). Positive correlations were shown between eating disorder and right ventral putamen activity to intense happy (p < 0.02) and neutral faces (p < 0.03). Exploratory analyses revealed few significant relationships between illness variables and medication upon neural activity in BD individuals. Limitations: Small sample size of predominantly medicated BD individuals. Conclusion: This study is the first to report relationships between comorbid symptom dimensions of substance abuse and eating disorder and prefrontal-cortical and subcortical-striatal activity to facial expressions in BD. Our findings suggest that these comorbid features may contribute to observed patterns of functional abnormalities in neural systems underlying mood regulation in BD.

An evaluation of coping ability as a guide to the treatment of persons diagnosed with schizophrenia and substance abuse

This dissertation introduced substance abuse to the Dynamic Vulnerability Formulation (DVF) and the social competence model to determine if the relationship between schizophrenic symptomatology and coping ability in the DVF applied also to the dually diagnosed schizophrenic or if these variables needed to be modified. It compared the coping abilities of dually and singly diagnosed clients in day treatment and identified, examined, and assessed the relative influence of relevant mediating variables on two dimensions of coping ability of the dually diagnosed: coping skills and coping effort. These variables were: presence of negative and nonnegative symptoms, duration of mental illness, type of substance used, and age of first substance use.^ A priori effect sizes based on previous empirical research were used to interpret the results related to the comparison of demographic, socioeconomic, and treatment characteristics between the singly and dually diagnosed study samples. The data suggested that the singly diagnosed group had higher coping skills than the dually diagnosed group, particularly in the areas of housing stability, work affect, and total social adjustment. The dually diagnosed group had lower scores on one aspect of coping effort--agency or self-efficacy. The data supported the presence of an inverse relationship between symptom severity and coping skills, particularly for the dually diagnosed group. The data did not support the presence of an inverse relationship between symptom severity and coping effort, but did suggest a positive relationship between symptom severity and one measure of coping effort, agency, for the dually diagnosed group. Regression equations using each summary measure of coping skill--social adjustment and role functioning--yielded statistically significant F-ratios. Thirty-six percent of the variance in social adjustment and thirty-one percent of the variance in role functioning were explained by the relative influence of the relevant variables. Both negative and non-negative symptoms were the only significant predictors of social adjustment. The non-negative symptoms variable was the sole significant predictor of role functioning. The results of this study provided partial support for the use of the Dynamic Vulnerability Formulation (DVF) with the dually diagnosed. ^

Hispanic adolescents with severe substance abuse problems: Parental involvement, acculturation-related factors, and attachment

The main objective of the study was to investigate the relationship between parent-related, acculturation-related, and substance use-related variables found within individual, familial/parental, peer and school adolescent ecological domains, in a clinical sample (i.e. adolescents who met criteria for a Diagnostic Statistical Manual-IV [DSMIV] clinical diagnosis of substance abuse/dependence) of Hispanic adolescents from Miami, Florida. ^ The sample for this study consisted of 94 adolescent-mother pairs. The adolescent sample was 65% male, and 35% female, with a mean age of 15 years. More than half of the adolescents were born in the United States (60%) and had resided in the U.S. for an average of 12 years; 80% of the caregivers (primarily mothers) were foreign-born and lived in the U.S. for an average of 21 years. ^ Correlation and hierarchical regression were used to answer the research questions. The findings indicate that the hypothesized model and corresponding anticipated effect of the relationship between parental school and peer involvement on adolescents’ frequency of alcohol, marijuana and cocaine use was not supported by the data. Parental “acculturation-related” variables did not explain any of the variance in adolescent substance use frequency in this sample. Mediation and moderation models were not supported either. However, some interesting relationships were found: ^ The larger the acculturation gap, the lower the parental involvement in school tended to be (r = -.21, p < .05). Adolescents who experienced a greater acculturation gap with their parents (-.81, p >.01) had an earlier onset of marijuana (-.33, p < .01) and cocaine use (r = -.24, p <.01). The less acculturated parents experienced more parenting stress (r = -.31, p = < .01). Attachment was positively associated with parental peer involvement (r = .24, p < .05) and inversely associated with parenting acculturative stress (r = -.24, p < .05). Attachment was also positively associated with marijuana (r = .39, p < .01) and cocaine use (r = .33, p < .01). Adolescent males reported being more attached to their mothers when compared to adolescent females (r = .22, p >.05), they also reported using marijuana more frequently than females (.21, p >.05). ^

Differences in treatment and intervention needs of girls arrested for status versus criminal offenses

The purpose of this research was to explore the differences in factors associated with girls' status and criminal arrests. This study used data from six juvenile justice programs in multiple states, which was derived from the Juvenile Assessment and Intervention System (JAIS). The sample of 908 adolescent girls (ages 13-19) was ethnically and racially diverse (41% African American, 32% white, 12% Hispanic, 11% Native American and 4% Other). A structural equation model (SEM) was analyzed which tested the potential effects of adolescent substance use, truancy, suicidal ideation/attempt, self-harm, peer legal trouble, parental criminal history and parental and non-parental abuse on type of offense (status and criminal) and whether any of these relationships varied as a function of race/ethnicity. ^ Complex relationships emerged regarding both status and more serious criminal arrests. One of the most important findings was that distinct and different patterns of factors were associated with status arrests compared to criminal arrests. For example, truancy and parental abuse were directly associated with status offenses, whereas parental criminal history was directly related to criminal arrests. However, both status and criminal arrests shared common associations, including substance use, which signifies that certain variables are influential regarding both non-criminal and more serious crimes. In addition, significant meditating influences were observed which help to explain some underlying mechanisms involved in girls' arrest patterns. Finally, race/ethnicity moderated a key relationship, which has serious implications for treatment. ^ In conclusion, the present study is an important contribution to research regarding girls' delinquency in that it overcomes limitations in the existing literature in four primary areas: (1) it utilizes a large, multi-state, ethnically and racially diverse sample of justice system-involved girls, (2) it examines numerous co-occurring factors influencing delinquency from multiple domains (family, school, peers, etc.) simultaneously, (3) it formally examines race/ethnicity as a moderator of these multivariate relationships, and (4) it looks at status and criminal arrests independently in order to highlight possible differences in the patterning of risk factors associated with each. These findings have important implications for prevention, treatment and interventions with girls involved in the juvenile justice system.^

``This is your brain on drugs'': The public policy of anti -drug programming. An exploratory analysis of media and other sources of drug information for adolescents

In the 1980s, government agencies sought to utilize research on drug use prevention to design media campaigns. Enlisting the assistance of the national media, several campaigns were designed and initiated to bring anti-drug use messages to adolescents in the form of public service advertising. This research explores the sources of information selected by adolescents in grades 7 through 12 and how the selection of media and other sources of information relate to drug use behavior and attitudes and perceptions related to risk/harm and disapproval of friends' drug-using activities.^ Data collected from 1989 to 1992 in the Miami Coalition School Survey provided a random selection of secondary school studies. The responses of these students were analyzed using multivariate statistical techniques.^ Although many of the students selected media as the source for most of their information on the effects of drugs on the people who use them, the selection of media was found to be positively related to alcohol use and negatively related to marijuana use. The selection of friends, brothers, or sisters was a statistically significant source for adolescents who smoke cigarettes, use alcohol or marijuana.^ The results indicate that the anti-drug use messages received by students may be canceled out by media messages perceived to advocate substance use and that a more persuasive source of information for adolescents may be friends and siblings. As federal reports suggest that the economic costs of drug abuse will reach an estimated $150 billion by 1997 if current trends continue, prevention policy that addresses the glamorization of substance use remains a national priority. Additionally, programs that advocate prevention within the peer cluster must be supported, as peers are an influential source for both inspiring and possibly preventing drug use behavior. ^

The influence of gender on perceived treatment need among a community sample of substance users

Purpose: Most individuals do not perceive a need for substance use treatment despite meeting diagnostic criteria for substance use disorders and they are least likely to pursue treatment voluntarily. There are also those who perceive a need for treatment and yet do not pursue it. This study aimed to understand which factors increase the likelihood of perceiving a need for treatment for individuals who meet diagnostic criteria for substance use disorders in the hopes to better assist with more targeted efforts for gender-specific treatment recruitment and retention. Using Andersen and Newman's (1973/2005) model of individual determinants of healthcare utilization, the central hypothesis of the study was that gender moderates the relationship between substance use problem severity and perceived treatment need, so that women with increasing problems due to their use of substances are more likely than men to perceive a need for treatment. Additional predisposing and enabling factors from Andersen and Newman's (1973/2005) model were included in the study to understand their impact on perceived need. Method: The study was a secondary data analysis of the 2010 National Survey on Drug Use and Health (NSDUH) using logistic regression. The weighted sample consisted of a total 20,077,235 American household residents (The unweighted sample was 5,484 participants). Results of the logistic regression were verified using Relogit software for rare events logistic regression due to the rare event of perceived treatment need (King & Zeng, 2001a; 2001b). Results: The moderating effect of female gender was not found. Conversely, men were significantly more likely than women to perceive a need for treatment as substance use problem severity increased. The study also found that a number of factors such as race, ethnicity, socioeconomic status, age, marital status, education, co-occurring mental health disorders, and prior treatment history differently impacted the likelihood of perceiving a need for treatment among men and women. Conclusion: Perceived treatment need among individuals who meet criteria for substance use disorders is rare, but identifying factors associated with an increased likelihood of perceiving need for treatment can help the development of gender-appropriate outreach and recruitment for social work treatment, and public health messages.