Comorbid trajectories of tobacco and marijuana use as related to psychological outcomes

Risk Modifying Factors of Anxiety and Depressive Disorders, Using the Example of a Population Study in the Żywiec District

The aim of this study was the identification of the risk modifying factors of anxiety and depressive disorders based on a population study. This study was conducted in a randomly selected group of 1659 adult inhabitants of the Żywiec district. Anonymous questionnaires consisting of a proprietary questionnaire and the Hospital Anxiety and Depression Scale (HADS) were used to collect the data. The conducted analysis revealed that the factors increasing the risk of depressive disorders in the studied population were female gender, age over 60, retirement period, primary and vocational education, unemployment, mental work and absolute lack of physical activity, but also daily and intensive sports, heavy smoking, chronic somatic diseases and misuse of sleeping pills and over-the-counter sedatives. Anxiety disorders occurred more often in the group of unemployed, self-employed or retired people. They also occurred more often in the group of people who do not perform any physical activity and use alcohol every day, but also among those who maintain abstinence, regularly smoke tobacco and use stimulants, suffer from somatic diseases and overuse sleeping drugs. Disease preventive factors for anxiety disorders and depression were a constant form of employment, moderate and regular physical activity, avoiding the use of psychoactive substances and the regular treatment of comorbid somatic diseases and insomnia.

Maternal smoking trajectory during pregnancy predicts offspring's smoking and substance use - The Northern Finland birth cohort 1966 study

The aim was to characterize the association of maternal smoking trajectory during pregnancy with offspring's smoking, alcohol and substance use behavior. We used the prospective Northern Finland Birth Cohort 1966 study including 11,653 mothers and their offspring followed up from mothers' mid-pregnancy to age of 46 years. Main exposure was number of smoked cigarettes per day at each month of pregnancy. Outcome measures were offspring's smoking, alcohol and drug use at age 14, starting age of smoking, ever-smoking, and smoked pack-years until age 46. Four maternal smoking trajectories during pregnancy were identified with latent class trajectory modelling, namely "non-smokers" (86.0% of mothers), "early quitters" (2.0%), "late quitters" (2.1%), and "consistent smokers" (9.9%). In comparison to non-smokers, all maternal smoking was associated with offspring's increased odds of lifetime smoking adjusted for sex of the child, father's smoking, occupational status and place of residence of family, marital status and mood of mother, and desirability of pregnancy. The consistent smoker's class was associated with offspring's number of smoked pack years by midlife (median [interquartile range]: 8.3 [1.4-17.4] vs. 4.8 [0.0-13.0], p = 0.028), and alcohol use in young age (odds ratio 1.23 [95% confidence interval 1.05-1.43]). Overall, to prevent parent-offspring transmission of smoking, the cessation support should target women planning pregnancy. Negative effects of maternal continuous smoking during pregnancy include all substance use and reach up to offspring's middle age.

Discounting, Cognitive Inflexibility, and Antisocial Traits as Predictors of Adolescent Drug Involvement

Cognitive impairments, such as steep delay discounting, have been correlated with substance-related disorders. However, antisocial traits, cognitive inflexibility, and loss discounting have been barely considered despite having a high relationship with problematic consumption. This study aims to identify the predictive power of these variables in four types of drug use. Fifty-two adolescents (age range of 13 to 19 years) were assessed with a substance involvement test, four discounting tasks using $3,000, a card sorting test, and antisocial screening. Discriminant analysis with simultaneous estimation and varimax rotation was carried out. Function one included discounting of both losses, function two AT and CI, and function three probabilistic gains. The three functions explained 60.1% of the variance. The results show that preference for small and soon punishments and larger and unlikely punishments distinguished non-use and experimental use of moderate consumption and problematic consumption. High antisocial traits and low cognitive inflexibility distinguished experimental use groups of non-use. Risk-taking did not discriminate effectively between moderate consumption and problematic consumption. A replication of this study with a larger sample size is recommended to verify the results.

Effect of Δ9-Tetrahydrocannabinol on frontostriatal resting state functional connectivity and subjective euphoric response in healthy young adults

BACKGROUND

Few studies have examined how Δ9-Tetrahydrocannabinol (THC), the main psychoactive component of cannabis, impacts brain reward circuitry in humans. In this study, we examined if an acute dose of THC altered resting state functional connectivity between the striatum and prefrontal cortex among healthy young adults with limited cannabis use.

METHODS

Participants received THC (n = 24) or placebo (n = 22) in a double-blind, randomized, between-subject design. Participants completed self-report measures of euphoria and drug-liking throughout the visit. Approximately 120 min after drug administration, participants completed an 8-min resting state functional MRI (rs-fMRI) scan. We utilized seed-based connectivity of the striatum (bilateral putamen, caudate, and NAcc seeds) to the frontal cortex.

RESULTS

Individuals who received THC demonstrated greater rs-fMRI connectivity between the right NAcc and regions of the medial prefrontal cortex (mPFC) (p-values<0.05, corrected) and higher subjective euphoria ratings (p = .03) compared to compared to individuals who received placebo. Higher ratings of euphoria were related to greater right NAcc-dorsal mPFC (dmPFC) connectivity for the THC group (p=.03), but not for the placebo group (p=.98).

CONCLUSIONS

This is one of the first studies to examine rs-fMRI connectivity in healthy young non-users after THC administration. We found individuals receiving THC show greater rs-fMRI connectivity between the NAcc and mPFC, regions implicated in reward, compared to individuals receiving placebo. In addition, individuals receiving THC reported higher subjective euphoria ratings, which were positively associated with NAcc-dmPFC connectivity. Overall, our findings suggest THC may produce subjective and neural reward responses that contribute to the rewarding, reinforcing properties of cannabis.

Cannabis users demonstrate enhanced neural reactivity to reward: An event-related potential and time-frequency EEG study

INTRODUCTION

Disruptions in neural measures of reward responsiveness are implicated in risk for and the development of Substance Use Disorders (SUDs) in general, but it is not clear if this is also true for Cannabis Use Disorder (CUD). To date, no studies have examined neural reward responsiveness in cannabis users using EEG.

METHODS

Cannabis users (CU; n = 67) and non-users (n = 60) were drawn from larger studies of individuals with and without internalizing and externalizing psychopathology. Groups were matched on current and lifetime psychopathology. Participants completed a validated monetary reward task during electroencephalogram (EEG). One-way between subject analysis of covariance (ANCOVA) models examined group differences in four EEG indicators of reward responsiveness - the reward positivity (RewP) and feedback negativity (FN) event-related potentials and two time-frequency measures (reward-related delta and loss-related theta).

RESULTS

CU demonstrated an enhanced RewP to the attainment of monetary reward compared to non-users (p = .004), even after controlling for relevant covariates. Secondary analyses found that occasional CU, but not current CUD or remitted CUD, showed enhanced RewP compared to non-users. There were no significant differences in FN, reward-related delta, or loss-related theta time-frequency measures between groups.

CONCLUSIONS

To our knowledge, this is the first study to show preliminary evidence that CU have an enhanced RewP to reward and the extent of disruption may be related to CUD status. Our findings suggest that greater neural reward responsiveness may only be seen among occasional CU, not necessarily among CU with current or remitted CUD.

Lifelong smoking trajectories of Northern Finns are characterized by sociodemographic and lifestyle differences in a 46-year follow-up

Smoking remains among the leading causes of mortality worldwide. Obtaining a comprehensive understanding of a population’s smoking behaviour is essential for tobacco control. Here, we aim to characterize lifelong smoking patterns and explore underlying sociodemographic and lifestyle factors in a population-based birth cohort population followed up for 46 years. Our analysis is based on 5797 individuals from the Northern Finland Birth Cohort 1966 who self-reported their tobacco smoking behaviour at the ages of 14, 31 and 46. Data on sex, education, employment, body mass index, physical activity, alcohol consumption, and substance addiction were also collected at the follow-ups. We profile each individual’s annual smoking history from the age of 5 to 47, and conduct a latent class trajectory analysis on the data. We then characterize the identified smoking trajectory classes in terms of the background variables, and compare the heaviest smokers with other classes in order to reveal specific predictors of non-smoking and discontinued smoking. Six smoking trajectories are identified in our sample: never-smokers (class size 41.0%), youth smokers (12.6%), young adult quitters (10.8%), late adult quitters (10.5%), late starters (4.3%), and lifetime smokers (20.7%). Smoking is generally associated with male sex, lower socioeconomic status and unhealthier lifestyle. Multivariable between-class comparisons identify unemployment (odds ratio [OR] 1.28–1.45) and physical inactivity (OR 1.20–1.52) as significant predictors of lifetime smoking relative to any other class. Female sex increases the odds of never-smoking and youth smoking (OR 1.29–1.33), and male sex increases the odds of adult quitting (OR 1.30–1.41), relative to lifetime smoking. We expect future initiatives to benefit from our data by exploiting the identified predictors as direct targets of intervention, or as a means of identifying individuals who may benefit from such interventions.

Adolescent risk and protective factors predicting triple trajectories of substance use from adolescence into adulthood

OBJECTIVES

Since the number of individuals who use substances in the United States has markedly increased every year, substance use is a significant public health concern. The current study examines the possible risk and protective factors associated with triple comorbid trajectories of longitudinal alcohol, tobacco, and cannabis use from age 14 to 36.

METHODS

A community sample of 674 participants (53% African Americans and 47% Puerto Ricans; 60% females) were recruited from the Harlem Longitudinal Development Study. Multinomial logistic regression analyses were conducted to examine the associations between the risk (low self-control, peer drug use) and protective (parent-child attachment, family church attendance) factors at age 14 and membership in the triple trajectory groups derived from a multivariate growth mixture model.

RESULTS

Low self-control and peer drug use were associated with an increased likelihood of being a member in the triple comorbid trajectory groups compared to the reference group (i.e., low alcohol, no tobacco, and no cannabis use). On the other hand, parent-child attachment and family church attendance were associated with a decreased likelihood of being a member in the triple comorbid trajectory groups compared to the reference group.

CONCLUSIONS

Treatment programs for adolescents who use substances may be more helpful if their parents and/or friends could also participate together with the adolescent, rather than only the adolescent participates in the treatment programs. Further research is needed to gain a greater understanding of the conceptual nature of the relationship between earlier risk and protective factors and later substance use patterns.

Sex Differences in the Association Between School Experiences and Marijuana Use Among African American Adolescents

This study examined whether past month marijuana use among African American adolescents differed based on school experiences and individual feelings toward school. A secondary analysis of the 2012 National Survey on Drug Use and Health was conducted to answer research questions. Results from the multivariable logistic regression analyses revealed that female students at highest risk for recent use included those who held negative feelings toward school (OR 2.723, CI 1.683, 4.406, p < .001), felt courses were not interesting (OR 2.695, CI 1.513, 4.798, p < .01), and received mostly C's/D's/ F's in the last semester (OR 2.520, CI 1.614, 6.711,p < .001). For males, results indicated that male students at highest risk included those who held negative feelings toward school (OR 2.364, CI 1.365, 4.094, p < .01), felt things learned in school would not be important later in life (OR 3.470, CI 1.951, 6.173, p < .001), and received mostly C's/ D's/F's in the last semester (OR 2.733, CI 1.734, 4.309, p < .001). In the final model, of those who felt that most or all students in their grade used marijuana, males were 3 ½ times (OR 3.418, CI 1.741, 6.711, p < .001) and females were 8 times (OR 8.288, CI 3.526, 19.480, p < .001) more likely to have recently used marijuana. Such findings can be used by prevention specialists and health educators to develop and implement marijuana prevention programs and interventions specifically tailored to African American adolescents. Recommendations for future research are included.

Psychological Risk Factors for Alcohol, Cannabis, and Various Tobacco Use among Young Adults: A Longitudinal Analysis

BACKGROUND

Alcohol, cannabis, and tobacco use are prevalent in young adults and may be differentially related to psychological symptoms characterized as externalizing or internalizing.

OBJECTIVES

This study examined the use of alcohol, cannabis, and various tobacco products in relation to externalizing (ADHD) versus internalizing factors (depression, anxiety), hypothesizing alcohol and cannabis use are associated with externalizing factors whereas tobacco use is related to internalizing factors.

METHODS

Data from a 2-year longitudinal study of 2,397 US college students (aged 18-25) launched in 2014 were analyzed. Adult ADHD Self-Report Scale, Patient Health Questionnaire-9 item (assessing depressive symptoms), and the Zung Self-Rating Anxiety Scale scores were examined in relation to subsequent past 30-day use of alcohol, cannabis, and tobacco products (cigarettes, little cigars/cigarillos, smokeless tobacco, e-cigarettes, hookah), as well as nicotine dependence per the Hooked on Nicotine Checklist.

RESULTS

Participants were 20.49 (SD = 1.93) years old, 64.7% female, and 65.5% White. In multivariable analyses, greater ADHD symptoms predicted alcohol and cannabis use (p = .042 and p = .019, respectively). Cigarette and little cigar/cigarillo use were predicted by greater depressive (p = .001 and p = .002, respectively), and anxiety symptoms (p = .020 and p = .027, respectively). Nicotine dependence was correlated with greater anxiety symptoms (p = .026). Counter to hypotheses, smokeless tobacco use was predicted by greater ADHD symptoms (p = .050); neither e-cigarette nor hookah use were predicted by these psychological symptoms. Conclusions/Importance: Research examining risk factors for tobacco use must distinguish among the various tobacco products. Moreover, interventions may need to differentially target use of distinct substances, including among the range of tobacco products.

Marijuana Use and Depressive Symptoms; Gender Differences in African American Adolescents

Introduction: This study aimed to examine gender differences in the bidirectional associations between marijuana use and depressive symptoms among African American adolescents. The study also tested gender differences in the effects of socioeconomic status, maternal support, and friends' drug use on adolescents' depressive symptoms and marijuana use. Methods: This is a secondary analysis of the Flint Adolescent Study (FAS). Six hundred and eighty one African American adolescents (335 males and 346 females) were followed for 3 years, from 1995 (mean age 16) to 1997 (mean age 19). Depressive symptoms (Brief Symptom Inventory) and marijuana use were measured annually during the follow up. We used multi-group latent growth curve modeling to explore the reciprocal associations between depressive symptoms and marijuana use over time based on gender. Results: Baseline marijuana use was predictive of an increase in depressive symptoms over time among male but not female African American adolescents. Baseline depressive symptoms were not predictive of an increase in marijuana use among male or female adolescents. Conclusion: Study findings suggest that male African American adolescents who use marijuana are at an increased risk of subsequent depressive symptoms. Interventions that combine screening and treatment for marijuana use and depression may be indicated for African American male adolescents.

Screening in Primary Care: What Is the Best Way to Identify At-Risk Youth for Substance Use?

BACKGROUND

It is important to improve primary care providers' capability to identify youth at risk for alcohol and other drug use. To our knowledge, this is the first study to use Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria to compare screeners for youth for both alcohol and marijuana, given that these are the most frequently used substances by this age group.

METHODS

We compared the psychometric performance of 4 screeners: the National Institute on Alcohol Abuse and Alcoholism Screening Guide (NIAAA SG), the Alcohol Use Disorders Identification Test, the Car-Relax-Alone-Forget-Family and Friends-Trouble (CRAFFT) screener, and the Personal Experience Screening Questionnaire Problem Severity Scale (PESQ-PS) in identifying alcohol and marijuana use outcomes. Youth age 12 through 18 (N = 1573; 27% black, 51% Hispanic) were screened with the NIAAA SG, followed by a Web survey that included the other screeners and outcomes.

RESULTS

Sensitivity for alcohol outcomes indicated that the NIAAA SG (0.87) did not perform as well as the CRAFFT (0.97) or PESQ-PS (0.97) screeners but performed better than the Alcohol Use Disorders Identification Test (0.70). The pattern for sensitivity across screeners for marijuana outcomes was similar.

CONCLUSIONS

An important tradeoff in primary care settings is precision versus practicality. Because of brevity and focus on frequency of drinking, the NIAAA SG offers ease of administration and is good at identifying youth with probably problematic drinking levels. The PESQ-PS and the CRAFFT correctly identify more at-risk youth for alcohol and marijuana than the NIAAA SG. Future work is needed to elucidate how to efficiently and accurately identify at-risk youth in the primary care setting, including determining the best cutoff points to use to increase sensitivity.

Comorbid trajectories of substance use as predictors of Antisocial Personality Disorder, Major Depressive Episode, and Generalized Anxiety Disorder

OBJECTIVE

To determine longitudinal associations between patterns of comorbid cigarette, alcohol, and marijuana use and Antisocial Personality Disorder (ASPD), Major Depressive Episode (MDE), and Generalized Anxiety Disorder (GAD) in adulthood.

METHOD

A random community-based sample [X̅ age=36.6 (SD=2.8)] from the Children and Adults in the Community Study, an on-going investigation of substance use and psychiatric disorders. Data were collected at six time waves. Conjoint trajectories of cigarette, alcohol, and marijuana use spanning adolescence to adulthood were determined; multivariable logistic regression analyses assessed associations between trajectory group membership and having ASPD, MDE, or GAD in adulthood.

RESULTS

Five conjoint trajectory groups were obtained: HHH (chronic cigarette, alcohol, and marijuana use), DDD (delayed/late-starting cigarette, alcohol, and marijuana use), LML (low/no smoking, moderate alcohol use, occasional marijuana use), HMN (chronic smoking, moderate alcohol use, no marijuana use), and NON (occasional alcohol use only). Compared with members of the NON group, those in the HHH group had significantly greater odds for having ASPD (Adjusted Odds Ratio [AOR]=28.52, 95% Confidence Interval [CI]=9.44-86.17), MDE (AOR=2.67, 95% CI=1.14-6.26), and GAD (AOR=6.39, 95% CI=2.62-15.56). Members of the DDD, LML, and HMN groups had weaker and less consistent associations with the three psychiatric outcomes.

CONCLUSIONS

In a large, community-based sample, long-term concurrent use of more than one substance was associated with both externalizing and internalizing psychiatric disorders in adulthood. Prevention and treatment programs might target individuals in the community and general clinical populations with comorbid substance use, even if they haven't been identified as having a substance use disorder.

Alcohol and marijuana use trajectories in a diverse longitudinal sample of adolescents: examining use patterns from age 11 to 17 years

AIMS

We tested race/ethnic differences in alcohol and marijuana (AM) trajectories (comprising an intercept term, reflecting overall probability of use, and a slope term, reflecting change in probability of use) during adolescence, whether AM use trajectories predicted high school outcomes, and whether outcomes differed by race/ethnicity after controlling for trajectory of AM use.

DESIGN

This longitudinal study involved 6509 youth from 16 middle schools in Southern California surveyed from age 11.5 (2008) to age 17 (2015) years; all surveys assessed AM use, and the final survey also examined high school outcomes.

SETTING

Youth completed five surveys in middle school and two on-line surveys in high school.

PARTICIPANTS

The sample was 50% male and 80% non-white.

MEASUREMENTS

Intercept (at 2.75 years post-baseline) and slope of AM use were examined as outcomes for race/ethnic differences. AM use trajectories were examined as predictors of academic performance and unpreparedness, social functioning, mental and physical health and delinquency.

FINDINGS

We found differences in trajectories of use by race/ethnicity, with white youth reporting a higher overall intercept of alcohol use compared to all other groups (versus Asian P < 0.001, black P = 0.001, multi-ethnic P = 0.008). Overall, examination of trajectories of use showed that adolescents with a higher alcohol use intercept term reported greater academic unpreparedness (P < 0.001) and delinquency (P < 0.001) at wave 7 in high school. In addition, youth with a higher intercept for marijuana use reported greater academic unpreparedness (P < 0.001) and delinquency (P < 0.001), and poorer academic performance (P = 0.032) and mental health (P = 0.002) in high school. At wave 7, compared to white youth, Hispanic and multi-ethnic youth reported poorer academic performance (P < 0.001 and P = 0.034, respectively); Asian, black and Hispanic youth reported higher academic unpreparedness (P < 0.001, P = 0.019, and P = 0.001); and Asian youth and multi-ethnic youth reported poorer physical health (P = 0.012 and P = 0.018) controlling for AM use.

CONCLUSIONS

Greater AM use was associated with worse functioning in high school for all youth. After controlling for AM use, non-white youth reported worse outcomes in high school for academics and health.

Distress tolerance predicts coping motives for marijuana use among treatment seeking young adults

Given increasing marijuana use and abuse among young adults in the United States and the associated physical and mental health consequences, it is important to improve our understanding of factors that may contribute to problematic marijuana use. A convergence of theory and research underscores the relevance of particular marijuana use motives generally, and coping-related motives specifically, in enhancing risk for marijuana use problems. Distress tolerance is a transdiagnostic emotion vulnerability factor that may relate to coping-related motives for marijuana use. The current study was designed to further explore this relationship within a treatment-seeking sample of young adults (Mage=24.40; SD=2.06 years). Results were consistent with hypotheses, suggesting distress tolerance is related to coping motives for marijuana use within this treatment-seeking sample, even after accounting for a number of theoretically relevant covariates. Theoretical and applied implications of distress tolerance as it relates to coping motives for marijuana use as treatment targets are discussed.

Psychosocial determinants of marijuana use among African American youth

This study examines the psychosocial determinants of marijuana use among youth. A total of 7,488 African American middle and high school students from 133 metropolitan private and public schools completed a survey assessing psychosocial factors associated with annual marijuana use. The PRIDE survey, a nationally recognized survey on substance use, was used to assess the frequency of marijuana use and the influence of psychosocial factors on marijuana use among African American students. Results indicated that 18.5% of African American youth used marijuana in the past year. Males were significantly more likely than females to report using marijuana. Engaging in risky behaviors, such as getting in trouble at school and with police and attending a party with alcohol and other drugs, were significantly correlated with annual marijuana use. Conversely, having multiple parent, teacher, and school protective factors reduced annual marijuana use in this population. Such findings may assist prevention specialists in developing interventions to reduce and prevent marijuana use.

Trends in the Average Age of Quitting Among U.S. Adult Cigarette Smokers

INTRODUCTION

Quitting smoking at any age confers health benefits. However, studies have suggested that quitting by age 35 years leads to mortality rates similar to never smokers. This study assessed whether the mean and median ages of past-year quitting and prevalence of past-year quit attempts and successful quitting by age group changed over time.

METHODS

Data came from 113,599 adult cigarette smokers participating in the 1997-2012 National Health Interview Survey, an annual, cross-sectional household survey of U.S. adults aged ≥18 years. Mean and median ages of past-year successful abstinence (quit 6-12 months) were computed. Orthogonal polynomial logistic regression models tested for trends in quit attempts and successful quitting. Data were analyzed in 2014.

RESULTS

The average age of quitting (40.0 years in 1997-1998, 39.5 years in 2011-2012, p=0.80) and median age of quitting (35.9 years in 1997-1998, 36.9 years in 2011-2012, p=0.62) did not change over time. During 1997-2012, the percentage of smokers making a past-year quit attempt increased among those aged 25-34, 35-44, and 45-64 years; the percentage of smokers who reported quitting successfully increased among those aged 25-34 and 35-44 years (p<0.001).

CONCLUSIONS

Although the average age of quitting did not change over time, increases in past-year quit attempts and successful quitting occurred among adults aged 25-44 years. Proven population-level interventions--including price increases, mass media campaigns, comprehensive smoke-free policies, and health systems interventions--should be continued to further increase cessation, particularly among younger adults.

Gender differences in the associations among marijuana use, cigarette use, and symptoms of depression during adolescence and young adulthood

INTRODUCTION

As prevalence of marijuana use increases, it is important that we better understand how factors like gender, cigarette use, and depression are related to marijuana use during adolescence and young adulthood. We examined longitudinal relationships among these variables in adolescents moving into young adulthood who were studied longitudinally for six years.

METHODS

1263 individuals were included in the study. Participants were oversampled for ever-smoking a cigarette at baseline, when they were 15-16 years old. Frequency of cigarette smoking and marijuana use, as well as depression symptoms, were assessed at baseline, 6, 15, 24, 60 and 72 months.

RESULTS

Cigarette use frequency and depression symptoms were associated with frequency of marijuana use (p-values<.001), particularly in adolescence, but there were important gender differences in these relationships. Specifically, symptoms of depression were related to marijuana use frequency among males (p<.001), but not females (p=.62). In addition, frequency of marijuana use was associated with increased cigarette use frequency, especially among males who had higher symptoms of depression (p<.001). However, this effect was not seen among females. Exploratory analyses suggested that relationships between frequency of use and depression are specific to marijuana, not cigarettes.

CONCLUSIONS

Marijuana use is strongly related to depression symptoms and cigarette use frequency in males, indicating that in males these detrimental factors converge, whereas in females they do not. Gender differences in the factors related to marijuana use may mean that there are different risks for and consequences from use and have implications for prevention and intervention efforts.

Gateway to curiosity: Medical marijuana ads and intention and use during middle school

Over the past several years, medical marijuana has received increased attention in the media, and marijuana use has increased across the United States. Studies suggest that as marijuana has become more accessible and adults have become more tolerant regarding marijuana use, adolescents perceive marijuana as more beneficial and are more likely to use if they are living in an environment that is more tolerant of marijuana use. One factor that may influence adolescents' perceptions about marijuana and marijuana use is their exposure to advertising of this product. We surveyed sixth- to eighth-grade youth in 2010 and 2011 in 16 middle schools in Southern California (n = 8,214; 50% male; 52% Hispanic; mean age = 13 years) and assessed exposure to advertising for medical marijuana, marijuana intentions, and marijuana use. Cross-lagged regressions showed a reciprocal association of advertising exposure with marijuana use and intentions during middle school. Greater initial medical marijuana advertising exposure was significantly associated with a higher probability of marijuana use and stronger intentions to use 1 year later, and initial marijuana use and stronger intentions to use were associated with greater medical marijuana advertising exposure 1 year later. Prevention programs need to better explain medical marijuana to youth, providing information on the context for proper medical use of this drug and the potential harms from use during this developmental period. Furthermore, as this is a new frontier, it is important to consider regulating medical marijuana advertisements, as is currently done for alcohol and tobacco products.