Trajectories Of Marijuana Use Research Articles

Longitudinal trajectories of marijuana use in tobacco products among young adult Texas college students from 2015 to 2019.

To measure longitudinal trajectories of marijuana use in four tobacco/nicotine products (hand-rolled cigarettes/spliffs, cigars/blunts, hookah, and e-cigarettes) among young adult Texas college students from 2015 to 2019. This study used six consecutive waves of data from the marketing and promotions across colleges in Texas project (Project M-PACT), a longitudinal study of the tobacco behaviors of young adult college students. The first four waves were collected every 6months (fall 2015-spring 2017), and the final two waves were conducted yearly (spring 2018 and 2019). Growth curve models measured trajectories of marijuana use in tobacco products across the 3.5-year period. A total of 4857 young adults from 24 colleges in the largest metropolitan areas of Texas, United States (Austin, Dallas, Houston, and San Antonio): mean age = 21.0, SD = 2.3; 64.2% assigned female; 36.1% non-Hispanic white, 31.0% Hispanic, and 33.0% other or combination race/ethnicity. Participants completed online surveys assessing their past 6-month use of marijuana in four tobacco products of interest (spliffs, blunts, hookah, and e-cigarettes) and socio-demographic variables (sex, race/ethnicity, age, 2-year/4-year college attendance, and sexual and gender minority identity). Observed vaping marijuana in e-cigarettes approximately doubled between the spring of 2015 and the spring of 2019, from 11.8% to 23.9% following a quadratic time trend (linear OR = 0.84, 95% CI = 0.73-0.97, quadratic OR = 1.18, CI = 1.13-1.22). This same time period saw a quadratic decline in using marijuana in hookah (P < 0.001) and no changes in using hand-rolled cigarettes/spliffs or cigars/blunts for marijuana delivery. The popularity of nicotine e-cigarettes appears to be expanding the avenues for marijuana delivery among young adults in Texas, United States.

Parental influences on marijuana use in emerging adulthood.

The purpose of this study was to gain a clearer understanding of the relation between parental relationship qualities and overall emerging adulthood (EA) marijuana use processes. The present study drew from an ethnically and socioeconomially diverse sample of EAs (ages 19-22) and their parents (n = 470) from the Pacific Northwest region. This study used parent-report and child-report data to capture measures of parenting and EA marijuana use outcomes. Latent Class Growth Analysis (LCGA) was used to model trajectories of marijuana use and risk factor analyses were used to examine how marijuana group membership varied by covariates and parental relationship qualities. Results revealed that lower levels of family cohesion and quality of parent-child communication were more likely to predict membership in the high-using groups and moderate-decreasing user groups in comparison to low-to-non users. Results also indicated that lower levels of frequency of parent-child communication were more likely to predict membership in the high-users group compared to the low-to-non users. Regarding parent knowledge of marijuana use, trends toward congruence and underestimation of EA marijuana use predicted membership in the high-using and moderate-decreasing groups compared to the low-to-non users. Study results indicate EAs in their early 20s may be more likely to engage in healthy decision-making regarding marijuana use in an environment that includes warm, supportive parent-child relationships where parents are aware of their EAs use without focusing on their EA's perceptions of risk. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Intergenerational marijuana use: A life course examination of the relationship between parental trajectories of marijuana use and the onset of marijuana use by offspring.

Prior research documents intergenerational (IG) continuity in marijuana use, with most work adopting a life course perspective. Incorporating a methodology that allows for the measurement of "patterns of behavior" instead of singular aspects of parent marijuana use (e.g., age of onset or frequency at any one age or ages), we investigated the simultaneous effects of parental age of onset, frequency, and duration of marijuana use across 3 periods of the life course (i.e., adolescence, emerging adulthood, and adulthood) on the timing of first marijuana use among offspring. Using prospective data from 2 companion studies, the Rochester Youth Development Study and the Rochester Intergenerational Study, we used group-based trajectory models to estimate trajectories (or patterns) of parental marijuana use spanning ages 14 to 31 among a birth cohort of 462 parents. We then examined the relationship between parental trajectories of marijuana use and the timing of the onset of marijuana use through age 25 among firstborn offspring. Both late-onset persistent use by parents and increasing chronic use spanning adolescence to adulthood by parents were associated with an increased likelihood of onset of marijuana use among offspring. The results underscore the importance of patterns of marijuana use for IG continuity in contrast to singular measures (e.g., age of onset among parents), which can obfuscate important IG patterns of continuity. Prevention and intervention programs should consider the entire history of parent use to better identify children most at risk for the onset of marijuana use in adolescence and emerging adulthood. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Cognitive aptitude, peers, and trajectories of marijuana use from adolescence through young adulthood.

Using a nationally representative longitudinal cohort, we examine how cognitive aptitude in early adolescence is associated with heterogeneous pathways of marijuana use from age sixteen through young adulthood. We also examine whether this relationship can be explained by the role of cognitive aptitude in the social organization of peer group deviance. Using the National Longitudinal Survey of Youth 1997, we identified 5 latent trajectories of frequency of marijuana use between ages 16 and 26: abstainers, dabblers, early heavy quitters, consistent users, and persistent heavy users. Multinomial regression assessed the relationship of cognitive aptitude in early adolescence with these latent trajectories, including the role of peer group substance use in this relationship. A one decile increase in cognitive aptitude in early adolescence is associated with greater relative risk of the dabbler trajectory (RR = 1.048; p < .001) and consistent user trajectory (RR = 1.126; p < .001), but lower relative risk of the early heavy quitter trajectory (RR = 0.917; p < .05) in comparison with the abstainer trajectory. There was no effect for the persistent heavy user trajectory. The inclusion of peer group substance use-either via illegal drugs or smoking-had no effect on these relationships. Adolescents who rate higher in cognitive aptitude during early adolescence may be more likely to enter into consistent but not extreme trajectories of marijuana use as they age into young adulthood. Cognition may not influence patterns of marijuana use over time via the organization of peer groups.

Not getting high with a little help from your friends: Social versus drug network correlates of marijuana use among YMSM

Substantial evidence has documented the importance of social connections in shaping health and drug use behaviors among adolescents and young adults. The current study extends previous research into the associations between network characteristics and drug use behavior among young men who have sex with men (YMSM) by 1) examining multiple network characteristics, 2) simultaneously assessing multiple network types (i.e., social and drug use), and 3) examining change in network characteristics and drug use behavior over time. Data for the current study comes from RADAR, a longitudinal cohort study of YMSM. Latent growth curve models examined the change in frequency of marijuana use across four observations and individual and network correlates of this change including: demographics, drug network size, drug network density, social network size, and social network density. Baseline frequency of marijuana use was positively associated with drug network size and density, while it was inversely related to social network size and density. In addition, increasing frequency of marijuana use was associated with increases in drug network size and density, while it was associated with decreases in social network size. These findings highlight the complexity of multiple network types (e.g., drug and social) and network structures (e.g., size and density) in understanding drug use behavior among YMSM. Furthermore, as changes in drug and social networks may be indicative of changes in marijuana use, peer relationships may be especially important in understanding an individual's trajectories of marijuana use.

Patterns of marijuana use and physical health indicators among Canadian youth.

We examine how trajectories of marijuana use in Canadian youth (ages 15 to 28) are related to physical health indicators in adolescence and young adulthood. Youth were initially recruited in 2003 (N = 662; 48% male; ages 12 to 18) and followed for six waves. Five trajectories of marijuana use (Abstainers‐29%, Occasional users‐27%, Decreasers‐14%, Increasers‐20% and Chronic users‐11%) were identified. Chronic users reported more physical symptoms, poorer physical self‐concept, less physical activity, poorer eating practices, less sleep, and higher number of sexual partners during adolescence than other classes. Decreasers also reported poorer physical self‐concept and poorer eating practices than abstainers. Other trajectory classes showed few significant health problems. Chronic users also reported more acute health problems (i.e. serious injuries, early sexual debut, higher number of sexual partners, greater likelihood of having a STI) in young adulthood than all other classes contributing to costs of healthcare. Youth who engage in early, frequent and continued use of marijuana from adolescence to young adulthood are at‐risk of physical health problems in adolescence and young adulthood.

The Impact of the Urban Neighborhood Environment on Marijuana Trajectories During Emerging Adulthood.

Although there is little difference in rates of marijuana use between White and Black youth, Blacks have significantly higher rates of marijuana use and disorder in young adulthood. Theory suggests that factors tied to social disadvantage may explain this disparity, and neighborhood setting may be a key exposure. This study sought to identify trajectories of marijuana use in an urban sample during emerging adulthood, neighborhood contexts that predict these trajectories and social role transitions or "turning points" that may redirect them. Data are from a longitudinal cohort study of 378 primarily Black emerging adults who were first sampled in childhood based on their residence in low-income neighborhoods in Baltimore City and followed up annually. Group-based trajectory modeling identified three groups: No Use (68.8%), Declining Use (19.6%), and Chronic Use (11.7%). Living in close proximity to an alcohol outlet, and living in a neighborhood with more female-headed households and higher rates of violent crime increased the odds of membership in the Chronic Use group relative to No Use. Living in a neighborhood with more positive social activity increased the odds of membership in the Declining Use group relative to No Use. Not receiving a high school diploma or GED, pregnancy, and parenting also increased the odds of membership in the Declining Use group relative to No Use. These findings provide support that minority youth living in socially toxic and disordered neighborhoods are at increased risk of continuing on a trajectory of marijuana use during emerging adulthood while positive social activity in neighborhoods has the potential to redirect these negative trajectories. Besides taking on the responsibilities of parenting, emerging adults in the marijuana user groups had similar educational and family outcomes, suggesting that early marijuana use may have long-term implications.

Associations Between Marijuana Use Trajectories and Educational and Occupational Success in Young Adulthood

Adolescence and young adulthood is a critical stage when the economic foundations for life-long health are established. To date, there is little consensus as to whether marijuana use is associated with poor educational and occupational success in adulthood. We investigated associations between trajectories of marijuana use from ages 15 to 28 and multiple indicators of economic well-being in young adulthood including achievement levels (i.e., educational attainment and occupational prestige), work characteristics (i.e., full vs part-time employment, hours worked, annual income), financial strain (i.e., debt, trouble paying for necessities, delaying medical attention), and perceived workplace stress. Data were from the Victoria Healthy Youth Survey, a 10-year prospective study of a randomly recruited community sample of 662 youth (48% male; Mage = 15.5), followed biennially for six assessments. Models adjusted for baseline age, sex, SES, high school grades, heavy drinking, smoking, and internalizing and oppositional defiant disorder symptoms. Chronic users (our highest risk class) reported lower levels of educational attainment, lower occupational prestige, lower income, greater debt, and more difficulty paying for medical necessities in young adulthood compared to abstainers. Similarly, increasers also reported lower educational attainment, occupational prestige, and income. Decreasers, who had high early use but quit over time, showed resilience in economic well-being, performing similar to abstainers. Groups did not differ on employment status or perceived workplace stress. The findings indicate that early onset and persistent high or increasingly frequent use of marijuana in the transition from adolescent to young adulthood is associated with risks for achieving educational and occupational success, and subsequently health, in young adulthood.

Trajectories of marijuana use and the transition to adulthood

Alongside the rise of emerging adulthood, policy contexts for marijuana have rapidly changed, with increases in availability and the number of daily users. We identify heterogeneous pathways of marijuana use from age 16 to 26, and examine how these pathways differentiate adult role transitions by age 28. Latent class analyses identified five trajectories: abstainers, dabblers, consistent users, early heavy quitters, and persistent heavy users. Dabblers are no different from abstainers on educational and labor market outcomes, and both have higher odds of adult role transitions relative to heavier use classes. Dabblers differ from abstainers on certain family transitions, yet remain distinct from the heavier use classes. Besides parenthood, early heavy quitters and persistent heavy users are similar, suggesting that heavy use is particularly detrimental early during transitions to adulthood. Distinct trajectories of marijuana use may differentiate young people into divergent pathways of transitions to adulthood, which may have long-term implications.

Demographic and socioenvironmental predictors of premorbid marijuana use among patients with first-episode psychosis

ObjectiveWe identified, in subjects with first-episode psychosis, demographic and socioenvironmental predictors of three variables pertaining to premorbid marijuana use: age at initiation of marijuana use, trajectories of marijuana use in the five years prior to onset of psychosis, and the cumulative “dose” of marijuana intake in that same premorbid period. MethodsWe enrolled 247 first-episode psychosis patients and collected data on lifetime marijuana/alcohol/tobacco use, age at onset of psychosis, diverse socioenvironmental variables, premorbid adjustment, past traumatic experiences, perceived neighborhood-level social disorder, and cannabis use experiences. Bivariate tests were used to examine associations between the three premorbid marijuana use variables and hypothesized predictors. Regression models determined which variables remained independently significantly associated. ResultsAge at initiation of cigarette smoking was linked to earlier initiation, faster escalation, and higher cumulative dose of premorbid marijuana use. During childhood, poorer academic performance was predictive of an earlier age at initiation of marijuana use, while poorer sociability was related to more rapid escalation to daily use and a higher cumulative dose. As expected, experiencing euphoric effects was positively correlated with trajectories and cumulative dose, but having negative experiences was unrelated. Traumatic childhood/adolescent experiences were correlated with rapid escalation and amount of marijuana used, but not with age at initiation of marijuana use. ConclusionThese data expand the very limited literature on predictors of premorbid marijuana use in first-episode psychosis. Given its association with earlier age at onset of psychosis, and poorer outcomes among first-episode patients, prevention and treatment efforts should be further developed.

Marijuana use and service utilization among adolescents 7 years post substance use treatment

BackgroundIn an environment of increasingly liberal attitudes towards marijuana use and legalization, little is known about long-term trajectories of marijuana use among clinical samples of adolescents, and how these trajectories relate to health services utilization over time. MethodsLatent growth curve analysis was used to identify distinct trajectories of marijuana use in a clinical sample of adolescents (N=391) over 7 years post substance use treatment in an integrated health system. We examined psychiatric problems and polysubstance use associated with the identified trajectory groups using general linear models. Nonlinear mixed-effects logistic regressions were used to examine associations between health services use and the trajectory groups. ResultsWe identified three marijuana use trajectory groups: (1) Abstinent (n=117); (2) Low/Stable use (n=174); and (3) Increasing use (n=100). Average externalizing and anxiety/depression scores were significantly lower over time for the Abstinent group compared to the Increasing and Low/Stable groups. The Low Stable and the Increasing group had fewer psychiatric visits over time (p<0.05) and the Low/Stable group used more substance use treatment services over time compared with the Abstinent group (p<0.001). ConclusionsTreated adolescents showed distinct marijuana use patterns, one of which indicated a group of adolescents at risk of increased use over time. These individuals have greater psychiatric and polysubstance use over time, but may not be accessing needed services.

Trajectories of marijuana use from late childhood to late adolescence: Can Temperament × Experience interactions discriminate different trajectories of marijuana use?

Informed by developmental ecological and epigenetic theory, the current study examined three aims concerning adolescent marijuana use with a large community sample (N = 755; gender = 53% female) and six annual assessments that spanned 11-18 years of age. First, the natural history of adolescent marijuana use was modeled using a two-part latent growth curve analysis. Second, the validity of the mixtures was examined with a broad array of known correlates of adolescent marijuana use. Third, temperament (e.g., surgency, effortful control, and negative affect) was tested as individual differences that would enter into statistical interactions with peer substance use and prior alcohol and cigarette use to distinguish trajectories of marijuana use. The results suggested that escalations in marijuana use were observed for some youth who initiated marijuana use early in adolescence. Youth whose marijuana use did escalate substantially (10%) were distinguished on temperament, conduct disorder, peer delinquency, and pubertal development at baseline. Furthermore, hypothesized interactions between surgency and both peer substance use and prior substance use discriminated different patterns of marijuana use. The findings are discussed with respect to strategies for timing and content of preventive interventions.

Trajectories of Marijuana Use among HIV-seropositive and HIV-seronegative MSM in the Multicenter AIDS Cohort Study (MACS), 1984-2013.

To construct longitudinal trajectories of marijuana use in a sample of men who have sex with men living with or at-risk for HIV infection. We determined factors associated with distinct trajectories of use as well as those that serve to modify the course of the trajectory. Data were from 3658 [1439 HIV-seropositive (HIV+) and 2219 HIV-seronegative (HIV-)] participants of the Multicenter AIDS Cohort Study. Frequency of marijuana use was obtained semiannually over a 29-year period (1984-2013). Group-based trajectory models were used to identify the trajectories and to determine predictors and modifiers of the trajectories over time. Four distinct trajectories of marijuana use were identified: abstainer/infrequent (65%), decreaser (13%), increaser (12%) and chronic high (10%) use groups. HIV+ status was significantly associated with increased odds of membership in the decreaser, increaser and chronic high use groups. Alcohol, smoking, stimulant and other recreational drug use were associated with increasing marijuana use across all four trajectory groups. Antiretroviral therapy use over time was associated with decreasing marijuana use in the abstainer/infrequent and increaser trajectory groups. Having a detectable HIV viral load was associated with increasing marijuana use in the increaser group only. Future investigations are needed to determine whether long-term patterns of use are associated with adverse consequences especially among HIV+ persons.

Marijuana use from adolescence to adulthood: developmental trajectories and their outcomes.

The study assesses the degree to which individuals in different trajectories of marijuana use are similar or different in terms of unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, children living at home, and spouse/partner marijuana use at age 43. This study used a longitudinal design. The sample participants (N=548) were first studied at mean age 14 and last studied at mean age 43. Six trajectories of marijuana use were identified: chronic/heavy users (3.6%), increasing users (5.1%), chronic/occasional users (20%), decreasers (14.3%), quitters (22.5%), and nonusers/experimenters (34.5%). With three exceptions, as compared with being a nonuser/experimenter, a higher probability of belonging to the chronic/heavy, the increasing, or the chronic/occasional user trajectory group was significantly associated with a greater likelihood of unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, not having children who lived at home, and having a spouse/partner who used marijuana at early midlife. In addition, compared with being a quitter, a higher probability of belonging to the chronic/heavy user trajectory group was significantly associated with a higher likelihood of unconventional behavior, sensation seeking, emotional dysregulation, alcohol dependence/abuse, and spouse/partner marijuana use. Implications for intervention are presented. Trajectories of marijuana use, especially chronic/heavy use, increasing use, and chronic/occasional use, are associated with unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, having children who lived at home, and spouse/partner marijuana use at age 43. The importance of the findings for prevention and treatment programs are discussed.

Trajectories of marijuana use from adolescence to adulthood as predictors of unemployment status in the early forties.

To study the degree to which individuals in different trajectories of marijuana use are similar or different in terms of unemployment status at mean age 43. We gathered longitudinal data on a prospective cohort taken from a community sample (N = 548). Forty-nine percent of the original participants were females. Over 90% of the participants were white. The participants were followed from adolescence to early midlife. The mean ages of participants at the follow-up interviews were 14.1, 16.3, 22.3, 27.0, 31.9, 36.6, and 43.0, respectively. We used the growth mixture modeling (GMM) approach to identify the trajectories of marijuana use over a 29-year period. Five trajectories of marijuana use were identified: chronic users/decreasers (8.3%), quitters (18.6%), increasing users (7.3%), chronic occasional users (25.6%), and nonusers/experimenters (40.2%). Compared with nonusers/experimenters, chronic users/decreasers had a significantly higher likelihood of unemployment at mean age 43 (adjusted odds ratio = 3.51, 95% confidence interval = 1.13-10.91), even after controlling for the covariates. The results of the associations between the distinct trajectories of marijuana use and unemployment in early midlife indicate that it is important to develop intervention programs targeting chronic marijuana use as well as unemployment in individuals at this stage of development. Results from this study should encourage clinicians, teachers, and parents to assess and treat chronic marijuana use in adolescents.

Marijuana use trajectories during college predict health outcomes nine years post-matriculation

BackgroundSeveral studies have linked marijuana use with a variety of health outcomes among young adults. Information about marijuana’s long-term health effects is critically needed. MethodsData are from a ten-year study of 1253 young adults originally recruited as first-year college students and assessed annually thereafter. Six trajectories of marijuana use during college (Non-Use, Low-Stable, Early-Decline, College-Peak, Late-Increase, Chronic) were previously derived using latent variable growth mixture modeling. Nine health outcomes assessed in Year 10 (modal age 27) were regressed on a group membership variable for the six group trajectories, holding constant demographics, baseline health status, and alcohol and tobacco trajectory group membership. ResultsMarijuana trajectory groups differed significantly on seven of the nine outcomes (functional impairment due to injury, illness, or emotional problems; psychological distress; subjective well-being; and mental and physical health service utilization; all ps<.001), but not on general health rating or body mass index. Non-users fared better than the Late-Increase and Chronic groups on most physical and mental health outcomes. The declining groups (Early-Decline, College-Peak) fared better than the Chronic group on mental health outcomes. The Late-Increase group fared significantly worse than the stable groups (Non-Use, Low-Stable, Chronic) on both physical and mental health outcomes. ConclusionsEven occasional or time-limited marijuana use might have adverse effects on physical and mental health, perhaps enduring after several years of moderation or abstinence. Reducing marijuana use frequency might mitigate such effects. Individuals who escalate their marijuana use in their early twenties might be at especially high risk for adverse outcomes.

Trajectories of marijuana use from adolescence into adulthood: Environmental and individual correlates.

This study sought to identify trajectories of marijuana use in the Seattle Social Development Project (n = 808) sample from age 14 through 30, and to examine the extent to which individuals in these trajectories differed in their substance use problems, mental health, problem behavior, economic outcomes, and positive functioning at age 33. In addition, analyses examined between-trajectory differences in family, peer, school, neighborhood, individual, mental health, and substance use factors at key developmental points in adolescence and adulthood. Four trajectories of marijuana use were identified: nonusers (27%), adolescent-limited (21%), late-onset (20%), and chronic (32%) users. At age 33, the chronic trajectory was associated with the worst functioning overall. The late-onset group reported more substance use and sexual risk behavior than nonusers, but was otherwise not differentiated. The adolescent-limited group reported significantly lower educational and economic outcomes at age 33 than the late-onset and nonuser groups. In analyses at earlier ages, adolescent-limited and late-onset groups reported more problems in functioning during the period of escalation in use and improvement in functioning with the beginning of desistance. Implications for prevention are discussed, particularly the unique risks associated with early adolescent versus later onset of marijuana use.

Maternal age and trajectories of marijuana use over 17 years

hospital discharges. Linear regression was used to evaluate applications for medical marijuana over time. The application analysis was followed with an analysis exploring population growth as a confounder. Autocorrelation was evaluated and an AR1 structure was used as necessary. Finally, the association between monthly medical marijuana applications and monthly discharges coded as dependence was tested with linear regression to explore an ecologic dose response relationship. Results: From 2009 to 2013, both applications and discharges increased, where 4205 (p<0.001) additional applications were received per month, and a 0.9% (p<0.001) increase in population rate per month was detected in hospital discharges. This was not confounded by population growth. The association between applications and discharges was significant (p<0.001) but modest with only 1 discharge per 3159 applicants. Conclusions: Although statistically significant increases were detected over time, the relation between applications and discharges was small in the time period preceding the legalization of recreational sales. Other states considering the legalization of medical marijuana can use this report to assist in the evaluation of public health related outcomes of policy change. Financial support: NIH/NIDA, 5R01DA031816-04, The Impact of Medical Marijuana in Metropolitan Denver.

Up in Smoke: Neighborhood Contexts of Marijuana Use from Adolescence Through Young Adulthood.

The current understanding of the neighborhood contexts wherein adolescent substance use emerges remains limited by conflicting findings regarding geographic variation in, and neighborhood effects on, both the prevalence of and risk factors for such use. Using four waves of longitudinal data from the National Longitudinal Study of Adolescent to Adult Health [n = 18,697 (51% female, 54% White, 24% Black, 16 % Hispanic, 7% Asian, 2% American Indian/Other)], latent class analysis, and growth curve modeling, this study identified distinct neighborhood types--patterned by race/ethnicity, socioeconomic class, and geography--and explored how trajectories of adolescent and young adult marijuana use differed across neighborhood types. The results demonstrated complexity in neighborhood contexts, illustrating variation in trajectories of marijuana use across neighborhood types heretofore unobserved in neighborhoods research, and largely unexplained by key individual, family, and peer risk and protective factors. This approach highlights how social structural forces intersect and anchor trajectories of youth substance-using risk behavior

Trajectories of Marijuana Use Beginning in Adolescence Predict Tobacco Dependence in Adulthood

ABSTRACTBackground: Although the “stage theory” suggests that marijuana use occurs after the initiation of tobacco smoking, substantial evidence exists that they often occur concurrently, and that the use of marijuana may influence the use of tobacco. Methods: This study uses trajectory analysis to examine the relationship between marijuana use beginning in adolescence and adult tobacco dependence in a 5-wave longitudinal study (mean ages in each wave: 14, 19, 24, 29, and 32). The sample consisted of 816 participants (52% African Americans, 48% Puerto Ricans), of whom 60% were females. Logistic regression analyses were conducted to predict later tobacco dependence from earlier trajectories of marijuana use. Results: A higher Bayesian posterior probability (BPP) for the chronic marijuana use trajectory group (odds ratio [OR] = 10.93, P < .001; adjusted OR [AOR] = 10.40, P < .001), for the increasing marijuana use trajectory group (OR = 6.94, P < .001; AOR = 6.73, P < .001), and for the moderate marijuana use trajectory group (OR = 3.13, P < .001; AOR = 3.18, P < .001) was associated with an increased likelihood of being dependent on tobacco compared with the BPP of the no or low marijuana use trajectory group. Conclusions: The results underscore the value of considering multiple patterns of marijuana use within a person-centered approach. Thus, it would be appropriate for marijuana cessation programs to incorporate the prevention, assessment, and cessation of tobacco use in their health promotion strategies.