Marijuana-dependent Individuals Research Articles

Delay and probability discounting by drug-dependent cocaine and marijuana users.

Steep discounting of delayed monetary rewards by substance-dependent individuals is well-established. Less is known, however, about discounting other kinds of outcomes, and very little is known about discounting by marijuana-dependent individuals. To determine how cocaine-dependent individuals and marijuana-dependent individuals discount various delayed and probabilistic outcomes, both positive and negative. Marijuana-dependent individuals, cocaine-dependent individuals, and controls performed delay and probability discounting tasks with various hypothetical outcomes. The cocaine-dependent (but not the marijuana-dependent) group discounted delayed liquid rewards and monetary gains, but not delayed losses, more steeply than the control group. In contrast, the marijuana-dependent group (but not the cocaine-dependent group) discounted delayed monetary losses more steeply than controls. There were no group differences in discounting for any of the probabilistic outcomes. Factor analysis revealed a delayed gain factor, a probabilistic gain factor, and a delayed/probabilistic loss factor. The delayed gain factor scores for the cocaine-dependent group, but not the marijuana-dependent group, differed significantly from those of the control group. The groups did not differ in their probabilistic gain factor scores, and the marijuana-dependent group did not differ from the controls with respect to their loss factor scores. These results are inconsistent with the idea that steep discounting of both gains and losses and both delayed and probabilistic outcomes reflects a general impulsivity trait, as well as with the idea that all drug-dependent individuals are steep discounters. Rather, differences in discounting appear to be related to both the type of outcome and the specific drug on which individuals are dependent.

The relationship between general causality orientation and treatment outcome among marijuana-dependent adults

General causality orientations are motivational styles that are indicative of a person's belief about personal change and their motivation to change. The purpose of the current study was to investigate whether causality orientations were associated with marijuana treatment outcomes in a sample of marijuana-dependent individuals. A total of 74 participants (66% male) were recruited from the Seattle, Washington area and randomly assigned to receive a combination of motivational enhancement and cognitive behavioral therapy or the combination treatment plus additional “check-up” sessions. Follow-up assessments evaluated frequency of use, use-related problems, and marijuana use disorder symptoms through 9months. Causality orientations were relatively stable over time. Posttreatment Autonomy orientations were associated with lower frequency of use and Controlled orientations were associated with a reduction in use, problems, and marijuana use disorder symptoms. Autonomy and Controlled orientations were associated with readiness to change. Results suggest that both autonomous and controlled orientations have implications for response to treatment; perhaps for different reasons. Causality orientations may be a promising avenue of research to predict treatment response and outcome.

Effect of oxytocin on craving and stress response in marijuana-dependent individuals: a pilot study

Stress has been shown to be a significant factor in the maintenance of marijuana use. Oxytocin is a hypothalamic neuropeptide that has been shown to moderate behavioral responding to stress as well as play a role in the neuroadaptations that occur as a consequence of long-term drug use. The current study evaluated the impact of oxytocin pretreatment on craving, stress, and anxiety responses following a psychosocial stress task in marijuana-dependent individuals. In a laboratory setting, baseline measurements of craving (assessed using the Marijuana Craving Questionnaire; MCQ), salivary cortisol and dehydroepiandrosterone (DHEA), stress, and anxiety were collected in 16 participants (age 19-40) meeting DSM-IV criteria for marijuana dependence. Participants were then administered either oxytocin 40IU (n = 8) or placebo (n = 8) nasal spray prior to completion of the Trier Social Stress Task (TSST). Measurements were repeated pre-TSST, immediately post-TSST, and 5-, 35-, and 60-min post-TSST. Oxytocin reduced both MCQ total score and DHEA levels from before to after the TSST. It also decreased anxiety, but not subjective stress ratings. Although preliminary, these results suggest that oxytocin may play a role in the amelioration of stress-induced reactivity and craving in marijuana-dependent individuals.

Motives for using: A comparison of prescription opioid, marijuana and cocaine dependent individuals

Identification of the motives for drug use is critical to the development of effective interventions. Furthermore, consideration of the differences in motives for drug use across substance dependent populations may assist in tailoring interventions. To date, few studies have systematically compared motives for substance use across drug classes. The current study examined motives for drug use between non-treatment seeking individuals with current prescription opioid, marijuana, or cocaine dependence. Participants (N=227) completed the Inventory of Drug-Taking Situations (IDTS; Annis, Turner & Sklar,1997), which contains eight subscales assessing motives for drug use. The findings revealed that prescription opioid dependent individuals scored significantly higher than all other groups on the Physical Discomfort, Testing Personal Control and Conflict with Others subscales. Both the prescription opioid and cocaine dependent groups scored significantly higher than the marijuana group on the Urges or a Temptation to Use subscale. In contrast, marijuana dependent individuals scored highest on the Pleasant Emotions and Pleasant Times with Others subscales. The marked differences revealed in motives for drug use could be used in the development and implementation of specific treatment interventions for prescription opioid, marijuana and cocaine dependent individuals.

Stress- and cue-elicited craving and reactivity in marijuana-dependent individuals

Cue-elicited craving and stress responses have been identified as predictors of relapse in drug dependence, but little research exists on the contribution of these factors to marijuana use specifically. The aims of the present study were to evaluate (1) responses to a psychological stressor, (2) responses to marijuana-related cues, and (3) if an exposure to a psychological stressor augmented craving subsequently elicited by marijuana-related cue exposure in marijuana-dependent individuals. Subjective (craving, stress), neuroendocrine (adrenocorticotropic hormone (ACTH), cortisol), and physiologic responses to the presentation of neutral and marijuana cues were assessed after randomization to a stress (Trier Social Stress Task (TSST)) or non-stress control condition in marijuana-dependent individuals. Outcome measures were assessed at baseline, post-stressor/pre-neutral cue, post-neutral cue, and post-marijuana cue. Eighty-seven participants completed procedures (stress group, n = 45; non-stress group, n = 42). The stress group had a significant increase over the non-stress group in stress rating (p < 0.001), craving (p = 0.028), cortisol (p < 0.001), and ACTH (p < 0.001) after the completion of the TSST. An increased craving response for all participants was seen following the presentation of the marijuana cues (p = 0.005). Following the TSST or non-stress condition, the non-stress group had an increase in craving to marijuana cues as compared to neutral cues (p = 0.002); an increase in craving was not observed in the stress group (p = 0.404). Marijuana cue exposure and a social stressor increased craving in marijuana-dependent individuals. Completion of the TSST did not increase craving response to subsequent marijuana cue exposure.

Treatment of Cannabis Withdrawal Syndrome Using Cognitive-Behavioral Therapy and Relapse Prevention for Cannabis Dependence

Cannabis is the most frequently used illegal substance in the United States and Europe. There is a dramatic increase in the demand for treatment for cannabis dependence. The majority of marijuana-dependent individuals who enter treatment have difficulty in achieving and maintaining abstinence from cannabis partly due to the cannabis withdrawal syndrome. Onset of most symptoms occurs during the 1st week of abstinence and returns to baseline by the end of the 2nd week of abstinence. In our view, many cannabis users actually self-medicate for anxiety and depressive subclinical syndromes (i.e., anxiety, irritability, negative mood, physical symptoms, and decreased appetite). We now report a treatment study of 26 regular cannabis-dependent users with 12-week cognitive-behavioral therapy weekly sessions for the treatment of marijuana dependence. We also report a cognitive-behavioral relapse prevention group treatment of 12 regular cannabis-dependent users who quit smoking cannabis. Six members of the relapse pr...

Rimonabant-Induced Δ9-Tetrahydrocannabinol Withdrawal in Rhesus Monkeys: Discriminative Stimulus Effects and Other Withdrawal Signs

Marijuana-dependent individuals report using marijuana to alleviate withdrawal, suggesting that pharmacotherapy of marijuana withdrawal could promote abstinence. To identify potential pharmacotherapies for marijuana withdrawal, this study first characterized rimonabant-induced Δ⁹-tetrahydrocannabinol (Δ⁹-THC) withdrawal in rhesus monkeys by using drug discrimination and directly observable signs. Second, drugs were examined for their capacity to modify cannabinoid withdrawal. Monkeys receiving chronic Δ⁹-THC (1 mg/kg/12 h s.c.) discriminated the cannabinoid antagonist rimonabant (1 mg/kg i.v.) under a fixed ratio schedule of stimulus-shock termination. The discriminative stimulus effects of rimonabant were dose-dependent (ED₅₀ = 0.25 mg/kg) and accompanied by head shaking. In the absence of chronic Δ⁹-THC treatment (i.e., in nondependent monkeys), a larger dose (3.2 mg/kg) of rimonabant produced head shaking and tachycardia. Temporary discontinuation of Δ⁹-THC treatment resulted in increased responding on the rimonabant lever, head shaking, and activity during the dark cycle. The rimonabant discriminative stimulus was attenuated fully by Δ⁹-THC (at doses larger than mg/kg/12 h) and the cannabinoid agonist CP 55940 [5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]phenol], and partially by the cannabinoid agonist WIN 55212-2 [(<i>R</i>)-(+)-[2, 3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate] and the α₂-adrenergic agonist clonidine. In contrast, a benzodiazepine (diazepam) and monoamine agonist (cocaine) did not attenuate the rimonabant discriminative stimulus. Head shaking was attenuated by all test compounds. These results show that the discriminative stimulus effects of rimonabant in Δ⁹-THC-treated monkeys are a more pharmacologically selective measure of cannabinoid withdrawal than rimonabant-induced head shaking. These results suggest that cannabinoid and noncannabinoid (α₂-adrenergic) agonists are potentially useful therapeutics for marijuana dependence inasmuch as they attenuate the subjective experience of Δ⁹-THC withdrawal.

Delay discounting in current and former marijuana-dependent individuals.

Studies have found that a variety of drug-dependent groups discount delayed rewards more than matched controls. This study compared delay discounting for a hypothetical $1,000 reward among dependent marijuana users, former dependent marijuana users, and matched controls. Discounting of marijuana was also assessed in the currently marijuana-dependent group. No significant differences in discounting were detected among the groups; however, currently dependent users showed a trend to discount money more than the other 2 groups. Within the dependent marijuana group, marijuana was discounted more than money, and discounting for money and marijuana was significantly and positively correlated. Regression analyses indicated that delay discounting was more closely associated with tobacco use than marijuana use. A variety of questionnaires were also administered, including impulsivity questionnaires. Dependent marijuana users scored as significantly more impulsive on the Impulsiveness subscale of the Eysenck Impulsiveness-Venturesomeness-Empathy questionnaire than controls. However, the 3 groups did not significantly differ on several other personality questionnaires, including the Barratt Impulsivity Scale-11. The Stanford Time Perception Inventory Present-Fatalistic subscale was positively correlated with money and marijuana discounting, indicating that a greater sense of powerlessness over the future is related to greater delay discounting. Results suggest that current marijuana dependence may be associated with a trend toward increased delay discounting, but this effect size appears to be smaller for marijuana than for previously examined drugs.

Inventário de expectativas de resultados em usuários de maconha (IERUM): construção e validação

Introdução: Este estudo apresenta a construção e validação do Inventário de Expectativas de Resultados em Usuários de Maconha (IERUM), o qual avalia as expectativas de resultados em relação ao uso de maconha, podendo ser importante no tratamento e prognóstico dos dependentes químicos dessa substância. Método: O estudo foi realizado em uma amostra de 181 sujeitos usuários de maconha, homens (n = 145) e mulheres (n = 36), entre 18 e 55 anos (28,34±8,57); 118 estavam internados em unidade de dependência química, 23 em tratamento ambulatorial, 25 em grupo de autoajuda (narcóticos anônimos, alcoólatras anônimos) e 15 não estavam em tratamento. A escala de 17 itens foi criada a partir da experiência em dependência química e em validação de escalas, sendo realizada primeiramente a validação semântica. Resultados: De acordo com a análise fatorial, o IERUM dividiu-se em cinco fatores (aspectos emocionais, percepção, craving, aspectos cognitivos e sexualidade) que responderam por 60,18% da variância. Conclusão: O IERUM apresentou bons resultados psicométricos, podendo avaliar as expectativas de resultados relacionadas ao uso de maconha.

Cognitive deficits in marijuana users: Effects on motivational enhancement therapy plus cognitive behavioral therapy treatment outcome

Clinical variables that affect treatment outcome for marijuana-dependent individuals are not yet well understood, including the effects of cognitive functioning. To address this, level of cognitive functioning and treatment outcome were investigated. Twenty marijuana-dependent outpatients were administered a neuropsychological battery at treatment entry. All patients received 12 weekly individual sessions of combined motivational enhancement therapy and cognitive behavioral therapy. The Wilcoxon Exact Test was used to compare cognitive functioning test scores between completers and dropouts, and the Fisher Exact Test was used to compare proportion of negative urines between those with higher and lower scores on the cognitive tests. Marijuana abstinence was unrelated to cognitive functioning. However, dropouts scored significantly lower than completers on measures of abstract reasoning and processing accuracy, providing initial evidence that cognitive functioning plays a role in treatment retention of adult marijuana-dependent patients. If supported by further studies, the findings may help inform the development of interventions tailored for cognitively impaired marijuana-dependent patients.

Assessment of Club Drug Use in a Treatment‐Seeking Sample of Individuals with Marijuana Dependence

Club drug use is becoming increasingly popular in the United States and has been associated with chronic psychiatric symptoms and neuropsychological abnormalities. Patterns of club drug use and characteristics of club drug users are not homogeneous. Thus, treatment-seeking marijuana-dependent individuals may have a differential pattern of club drug use. Baseline assessments collected from 55 individuals participating in a pharmacological treatment study for marijuana dependence were examined. Individuals completed a 16-item self-report questionnaire assessing club drugs used, frequency and patterns of use, problems associated with use, and reasons for use. Subjects were primarily male (87.3%) and Caucasian (81.8%), with a mean age of 32.1 (+/-9.1 years). As expected, a large number of individuals had used ecstasy (75%). However, LSD and methamphetamine use was also reported by many users (82.5% and 47.5% respectively), with many individuals reporting the use of more than one club drug. Notably, 31.6% of individuals reported tolerance to club drugs. These results emphasize the significant co-occurrence of club drug use in marijuana-dependent individuals. This appears to be the first study to report on club drug use in treatment-seeking marijuana-dependent individuals. Clinical implications and directions for future research are discussed.

Severity of Dependence and Motivation for Treatment

Although marijuana dependence is prevalent, most individuals with marijuana dependence do not seek treatment. There are few data characterizing treatment seeking marijuana-dependent patients compared to patients presenting for treatment of other drugs regarding the severity of illness and motivation for treatment. Forty-two marijuana-dependent individuals were compared to 58 cocaine-dependent individuals seeking treatment. Compared to cocaine-dependent patients, those with marijuana dependence were younger and less likely to be dependent on alcohol or other drugs. Both groups had similar rates of comorbid anxiety and affective disorders. Marijuana-dependent individuals had lower total number of dependence symptoms but had a higher percentage of individuals endorsing withdrawal symptoms. Although marijuana-dependent individuals had less outpatient treatment exposure, the difference between the two groups was not significant and motivation for change, based on the University of Rhode Island Change Assessment, was similar for both groups of treatment seekers. However, the Circumstances, Motivation, Readiness for Treatment Scale suggested that cocaine-dependent individuals were more motivated for treatment. Taken together, these data suggest that treatment seeking marijuana-dependent individuals have substantial withdrawal dependence symptomatology although it is less clear if they are as motivated to seek out treatment as cocaine-dependent treatment seekers.

Abstinence at intake for marijuana dependence treatment predicts response

Abstinence prior to entering treatment is common among individuals seeking substance abuse treatment. The current study examined the relationship between abstinence at a pretreatment intake assessment and treatment response during outpatient treatment for marijuana dependence. At the intake assessment, 142 marijuana-dependent individuals completed past 30 day calendars of daily drug use. Forty-four (31%) participants were pretreatment abstainers, as defined by reports of one or more consecutive days of marijuana abstinence prior to the day of the intake assessment. Non-abstainers (69%) reported marijuana use the day prior or the day of the assessment. Pretreatment abstainers were more likely to enter treatment ( P<0.05) and showed better treatment response than non-abstainers. Abstainers provided 50% more marijuana-negative urine screens during treatment ( P<0.05), and more than three times as many abstainers reported no marijuana use ( P<0.01). The groups did not differ on treatment completion. Marijuana abstinence at the time of initial clinic contact appears to be a strong predictor of success during treatment. Pretreatment abstinence may prove useful as a pretreatment matching strategy that could improve outcomes and cost-effectiveness. Clinical trials might consider including pretreatment abstinence status as a stratification variable during participant assignment or as a covariate in outcome analyses.

Tobacco smoking in marijuana-dependent outpatients.

Among marijuana-dependent individuals, approximately 50% smoke tobacco. These individuals are exposed to increased risks of respiratory and other health problems. The current study examined whether tobacco smoking among marijuana-dependent individuals is also associated with increased psychosocial and substance abuse problems. Marijuana-dependent individuals (N=174) seeking treatment for marijuana problems completed a 2-3 h assessment. Current tobacco smokers were compared to ex-smokers and never smokers on demographic, psychosocial, and substance use characteristics, and treatment outcome. In addition to univariate comparisons, multivariate analyses using multinomial logistic regression were conducted to control for the correlated nature of the predictor variables. Current tobacco smokers earned less income and reported histories of more alcohol problems than never smokers and had fewer years of education, more legal problems, more psychiatric symptoms, and an earlier age of marijuana initiation than ex- and never smokers. Over the course of treatment, current tobacco smokers had significantly fewer marijuana-negative urine specimens and fewer weeks of continuous marijuana abstinence than ex-smokers. Current tobacco smokers appear to represent a subgroup of marijuana-dependent individuals who have increased psychosocial problems compared to ex- and never smokers and may not respond as well to treatment than ex-smokers.

Mental disorders and violence in a total birth cohort: results from the Dunedin Study.

We report on mental disorders and violence for a birth cohort of young adults, regardless of their contact with the health or justice systems. We studied 961 young adults who constituted 94% of a total-city birth cohort in New Zealand, April 1, 1972, through March 31, 1973. Past-year prevalence of mental disorders was measured using standardized DSM-III-R interviews. Past-year violence was measured using self-reports of criminal offending and a search of official conviction records. We also tested whether substance use before the violent offense, adolescent excessive perceptions of threat, and a juvenile history of conduct disorder accounted for the link between mental disorders and violence. Individuals meeting diagnostic criteria for alcohol dependence, marijuana dependence, and schizophrenia-spectrum disorder were 1.9 (95% confidence interval [CI], 1.0-3.5), 3.8 (95% CI, 2.2-6.8), and 2.5 (95% CI, 1.1-5.7) times, respectively, more likely than control subjects to be violent. Persons with at least 1 of these 3 disorders constituted one fifth of the sample, but they accounted for half of the sample's violent crimes (10% of violence risk was uniquely attributable to schizophrenia-spectrum disorder). Among alcohol-dependent individuals, violence was best explained by substance use before the offense; among marijuana-dependent individuals, by a juvenile history of conduct disorder; and among individuals with schizophrenia-spectrum disorder, by excessive perceptions of threat and a history of conduct disorder. In the age group committing most violent incidents, individuals with mental disorders account for a considerable amount of violence in the community. Different mental disorders are linked to violence via different core explanations, suggesting multiple-targeted prevention strategies.

Adults seeking treatment for marijuana dependence: A comparison with cocaine-dependent treatment seekers.

Sixty-two individuals seeking treatment for marijuana dependence completed a comprehensive assessment. Sociodemographics, substance use, psychosocial functioning, psychiatric symptoms, and medical status were compared with similar data collected from 70 treatment-seeking, cocaine-dependent individuals. Substantial psychosocial and psychiatric problems were observed in both groups. In general, the marijuana group reported substance-use histories and a range of impairment comparable with the cocaine group; however, they showed less severe dependence. The marijuana group was more ambivalent and less confident about stopping their marijuana use than the cocaine group was about stopping their cocaine use. These findings indicate that treatment-seeking, marijuana-dependent individuals exhibit substantial problems and that further efforts to develop effective treatments for this population are warranted.