Modulation of the effects of alcohol on driving-related psychomotor skills by chronic exposure to cannabis

RATIONALE: Many previous studies have reported that alcohol and cannabis produce additive psychomotor effects in acute combination, but few have explicitly tested whether chronic exposure to cannabis, in the absence of acute administration, alters the effects of alcohol on psychomotor performance. OBJECTIVES: To test whether long-term cannabis use modulates the effects of alcohol on psychomotor skills and self-reported mood and sensation. METHODS: Regular cannabis users (minimum: daily use for at least 3 years) and infrequent users (maximum: once-monthly use for at most 3 years) were matched for sex, age, alcohol intake and other drug use (14 participants in each group). Participants received alcohol (females 0.35 g/kg; males 0.45 g/kg) and placebo drinks. By urinalysis, only regular users tested positive for metabolites of Delta(9)-tetrahydrocannabinol; breath alcohol levels were similar between groups. Participants were tested on a computerised tracking task that has been used to screen drugs for adverse effects on driving. The task involved tracking a moving target on a computer screen while simultaneously responding to occasional presentations of stimuli in the periphery of the screen. RESULTS: Tracking accuracy was similar for both groups after placebo, but alcohol caused a significant deterioration in performance among infrequent cannabis users relative to regular users. These changes were mirrored by significant changes in self-reported scores for dizziness, measured by visual analogue scales. Alcohol slowed reaction times, but not differentially between groups. CONCLUSIONS: For psychomotor skills relevant to driving, chronic cannabis use (in the absence of acute administration) does not potentiate the effects of alcohol. In fact, the superior tracking accuracy of regular users relative to infrequent users after alcohol, and their lower scores for dizziness, suggest that chronic cannabis use may instead confer cross-tolerance to specific effects of alcohol on behaviour.     

Influences of alcohol and S-R uncertainty upon spatial localization time

Using a complete factorial design, choice reaction times of nine subjects were determined in three sessions on each of three days, after having consumed three beverages (placebo, beer, ethanol) with only a single beverage being consumed each day. Reaction time (the time to identify the location of a dot projected on a small screen) was measured from onset of stimulus presentation to the verbalization of a single-digit number associated with the area of the screen upon which the dot was projected. Reaction times were lengthened significantly by alcohol; increases in stimulus-response uncertainty, i.e., the number of possible locations and associated responses; and were lengthened more by alcohol as stimulus-response uncertainty was increased.The author is indebted to M. W. Perrine who is principal investigator of Public Health Research Grant MH-17683-01 under which this research was conducted.     

Effects of distance to treatment on subsequent alcohol consumption

Background: Distance and travel time are barriers to attending and completing drug and alcohol treatment. Few studies have examined proximity to treatment in relation to long-term outcomes.

Objectives: Aims were to examine effects of distance to treatment on alcohol consumption in the year after treatment intake; assess moderation of distance effects by treatment type; and test mediators of effects of distance to treatment on later alcohol use.

Methods: Data from clients in inpatient and outpatient alcohol treatment programmes in California (n?=?560) were used in linear regression models.

Results: There was a significant interaction between treatment type and distance on later drinking, with a significant positive association of distance to treatment with alcohol use after treatment for inpatient clients only. Among inpatient clients, none of the mediators significantly explained the relationship between a longer distance to treatment and greater subsequent alcohol use.

Conclusion: Inpatient clients may benefit from customized post-treatment recommendations to identify recovery resources near home.     

Driving under light and dark conditions: effects of alcohol and diazepam in young and older subjects

Objectives: Driving at night time increases accident risk due to visual conditions, fatigue and impaired performance. In addition, the use of alcohol and benzodiazepines may enhance the risks related to night-time driving. We studied these aspects of traffic safety in a simulated driving test with young and older drivers. Methods: In a double-blind, crossover, placebo-controlled study, nine young subjects, aged 22–24 years, performed simulated driving in both `light' and `dark' conditions, before and 1.5 h and 4 h after 0.8 g · kg⁻¹ ethanol (EOH) or 15 mg diazepam (DZ). Further, nine older subjects, aged 55–77 years, were similarly tested, but their EOH dose was 0.7 g · kg⁻¹ and the DZ dose was 10 mg. The tests were vigilance assessment on visual analogue scales (VAS), simulated driving under light and dark conditions for 6 min each and digit symbol substitution (DSS). Results: In the young subjects, both EOH and DZ similarly impaired DSS, with DZ causing more subjective drowsiness, clumsiness, mental slowness and poor overall performance than EOH. During simulated driving, both EOH and DZ impaired simple and complex tracking (EOH>DZ) and prolonged reaction times (EOH=DZ). Impairment of performance was practically identical under light and dark conditions. In the older subjects, objective performance on DSS was poorer (−30%) than that of the young ones, and subjective impairment was marginal. During simulated driving, the baseline levels of variables in older subjects showed definite impairment (errors +100% to +500%) when compared with young subjects. Active drugs impaired several variables (EOH>DZ), but the statistical significances were fewer than in young subjects. Increase in reaction errors reached statistical significance, especially while driving in the dark. Otherwise the driving results in light and dark were not notably different. Conclusion: Young subjects drew good baselines but were sensitive to EOH and DZ, whilst the older subjects showed poor baselines but were less sensitive to EOH and DZ. Although the baseline driving and responses to treatments were different in young and older subjects, their driving and psychomotor impairment were unaffected by light conditions. Received: 10 November 1999 / Accepted in revised form: 25 April 2000     

Placebo Effects of Edible Cannabis: Reported Intoxication Effects at a 30-Minute Delay

Previous research has demonstrated the ability of non-active smoked cannabis cigarettes to induce subjective effects of intoxication (i.e., placebo effect). No studies have been conduced to test whether edible forms of cannabis, which are associated with a significant delay in onset of effect, are able to induce a placebo effect. In the present study, 20 participants were told that they would receive an edible cannabis lollipop containing a high dose of tetrahydrocannabinol (THC), but were instead given a placebo control. Measures of intoxication and mood were taken at baseline, 30 minutes, and 60 minutes post-ingestion of the placebo lollipop. Results of four repeated-measures ANOVAs found significant and quadratic changes across time in cannabis (ARCI m-scale) intoxication (F(2,18) = 4.90, p = .01, η² = .22) and negative mood (F(2,18) = 3.99, p = .05, η² = .19). Changes in positive mood and the overall measure of general intoxication (ARCI) failed to reach significance. The present study provides preliminary evidence that a placebo effect can be induced with inert edible agents when participants are told that they are receiving active THC. This is the first known study to demonstrate an edible cannabis intoxication placebo effect.     

Cannabis cultivation in Spain: A profile of plantations,growers and production systems

BackgroundThe European market for cannabis derivatives is being transformed. The cultivation of cannabis within the EU and the shift of demand from hashish to domestic marihuana are key aspects of this transformation. Spain, formerly central to the trade of Moroccan hashish, is becoming a marihuana-producing country. The emergence of “import-substitution” has been researched in other EU countries, but thus far the Spanish case remains undocumented.MethodsThis paper is based on analysis of data of 748 cannabis plantations seized by Spanish police in 2013. The sample comprises reports of seizures identified through a survey of online news and police reports. “Event-analysis” methods were applied to these sources.ResultsThe analysis offers a typology of plantations, a profile of participants and the different production systems, and a model of regional distribution. Half of the plantations were small (less than 42 plants) and half contained between 100 and 1000 plants, with an average size of 261 plants. About three-quarters of plants were cultivated indoors using stolen electricity. 86% of all plants seized were from large-scale plantations (more than 220 plants). Most plantations were located along the Mediterranean coast, where population and tourism are concentrated. Over three-quarters of those indicted by police were Spanish (85%). Among the foreign owners of big plantations, Dutch nationals predominated. The number of seized plants by province was directly associated with the number of grow shops (β = 0.962, p < 0.001).ConclusionThe rise of large-scale cannabis plantations in the Spanish Mediterranean coast is increasingly replacing import of Moroccan hashish. Indoor cultivation supported by grow shops, that provide the technology and know-how, seem to be the dominant form of organization in this emerging industry. Large-scale plantations may have met most of the demand for marihuana in 2013.     

Psychological studies of marijuana and alcohol in man

Regular users of marijuana (cannabis sativa) were given smoked and orally administered marijuana, a placebo, or alcohol. They were unable to distinguish between smoked marijuana and the tetrahydrocannabinol-free placebo. The oral administration of tincture of cannabis produced primarily dysphoric symptoms and was similar to alcohol in this respect. The smoked marijuana altered pulse rate, time estimation, and EEG, but had no effect on a measure of field dependence or on a digit symbol substitution task. Both drugs appeared to be mild intoxicants in a laboratory setting. Consideration of the dose, prior experience with drugs, setting, and possible cross tolerance of marijuana and alcohol are important in evaluating the significance of the clinical effects.Based on a paper presented at the 125th Annual Meeting of the American Psychiatric Association, Bal Harbour, Florida, May 1969.This work was supported by National Institute of Mental Health grants K-1-MH-32904 and MH-15842, and by State of California Department of Mental Hygiene grant # 1–50.This paper does not reflect the views or policies of the California Department of Mental Hygiene.Staff Psychiatrist, and Assistant Professor of Psychiatry in Residence.Research Psychologist, and Associate Professor of Medial Psychology in Residence.     

A comparison of alcohol, tobacco and drug use as determined from household and school surveys

Comparisons of results from different types of surveys are necessary to establish the best and cheapest methods of assessing drug use. This paper reports results from a school survey and a household survey conducted in Ontario. Both surveys were done in 1983 and used unbiased samples of the population in the same age groups. There are some methodological differences between the two studies. Younger students were more likely to report the use of tobacco, alcohol and cannabis in the student survey than in the household survey. Similarly, older students (18 and 19) reported more alcohol use in the student survey. In general, the results indicate that respondents are more likely to give socially desirable answers to questions answered at home than at school. Also, alcohol and drug users may be more likely to be missed in household than in school studies as the former have a much higher non-response rate.     

Subgroup trends in alcohol and cannabis co-use and related harms during the rollout of recreational cannabis legalization in Washington state

BackgroundThe US state of Washington legalized recreational cannabis in 2012; how this impacted the co-use of cannabis and alcohol in the population overall and among key subgroups has not been examined. The aim of this study is to investigate changes in patterns of alcohol- and cannabis use and alcohol-related harms during the rollout of retail recreational cannabis stores.MethodsData come from six cross-sectional samples recruited between January 2014-October 2016 via Random Digit Dial procedures (N = 5492). Survey-weighted multivariable regression adjusting for gender, age, race/ethnicity, education, employment, marital status, cannabis use, and survey year were used for statistical analyses.ResultsIn the sample overall, no significant changes were observed in any alcohol use measures between 2014–2016, while the prevalence of cannabis use significantly (P < 0.05) increased from 25.0% to 31.7%, the prevalence of alcohol-related harms at home significantly decreased from 2.1% to 1.0%, and the prevalence of alcohol-related financial harms decreased from 1.5% to 0.8%. Both women and men significantly increased any cannabis use, while women also experienced significantly fewer alcohol-related harms at home and financial harms over time, and increases in the prevalence of cannabis users/non-drinkers. Those 18–29 years old significantly reduced the number of drinking days and overall volume in the past 30 days, and those 30–49 years old significantly decreased alcohol-related harms at home and financial harms. Those 50+ years old significantly increased any cannabis use and simultaneous use of cannabis and alcohol. Non-cannabis users slightly decreased average number of drinks/day, and cannabis users significantly decreased alcohol-related financial harms.ConclusionsBetween 2014–2016, the years during and immediately following the introduction of legal recreational cannabis stores in Washington state, there were no significant changes in cannabis and alcohol co-use or overall alcohol consumption. The only significant changes in the sample overall were an increase in any cannabis use and decreases in alcohol-related harms at home and alcohol-related financial harms.     

Effects of prenatal alcohol consumption on open-field behaviour and alcohol preference in rats

Throughout gestation pregnant Wistar rats consumed a liquid diet containing sustagen and ethanol. Control mothers were fed on lab chow. Subsequently, the offspring of the ethanol-fed mothers displayed significantly greater activity (ambulation and rearing) in an open-field test. Further, pups whose mothers were exposed to ethanol consumed significantly more ethanol in a preference test, compared to control offspring.     

Problematic alcohol and cannabis use among young adults: the roles of depression and discomfort and distress tolerance

Problematic substance use is associated with depression. Clarifying the relationship between substance use and depression remains an important research goal, with implications for prevention and treatment. Individual differences in the ability to tolerate negative physical and emotional sensations were hypothesized to play a role in substance use behaviors among depressed individuals. The present study investigated the roles of discomfort and distress tolerance in the relationship between alcohol and cannabis problems and depression among undergraduates (N=265). Consistent with other reports, depression was correlated with alcohol and cannabis problems. As predicated, distress tolerance mediated the relationships between depression and alcohol and cannabis problems. Interestingly, discomfort intolerance moderated the relationship between depression and cannabis problems such that depressed individuals with high discomfort tolerance were most vulnerable to cannabis problems. These data suggest that distress intolerance may at least partially account for alcohol and cannabis problems among depressed young adults whereas discomfort intolerance may actually serve a protective role in the development of cannabis problems.     

Prenatal alcohol consumption and open-field behaviour in rats: Effects of age at time of testing

Throughout gestation pregnant Wistar rats consumed a nutritious liquid diet containing 35% ethanol-derived calories. Control mothers were fed lab-chow. Subsequently, the offspring of the ethanolfed mothers displayed significantly greater activity (ambulation) in an open-field test at 28 and at 56 days of age, but not at 112 days of age. No differences in defecation were observed at any age.     

Cardiovascular variables,skin conductance and time estimation: Changes after the administration of small doses of nicotine

Three tobacco cigarettes with known content of nicotine and one lettuce-leaf cigarette were smoked by 24 young habitual smokers, at different times of day and fixed rates of smoking. Changes in various psychophysiological parameters were automatically recorded during the 60 min which followed smoking. Heart rate and forearm blood flow increases were found to be dose dependent, the latter occurring only after smoking at the fast rate and their duration simultaneous to the presence of active nicotine in the organism. Skin vasoconstriction, as measured by decreases in temperature showed itself more reactive to environmental stimuli than to drug effects. Significant increases in skin conductance levels lasting throughout the experimental session occurred immediately after smoking, although not related to drug effects. Diphasic effects of nicotine were, however, obtained with the two largest doses, at different times of day. This finding is discussed in relation to possible unspecific nicotine effects upon a preexisting level of activation. Nicotine did not influence subjective time estimates. However, a specific pattern of responses occurred. This is discussed in terms of disruption of the timing task and a gradual re-organization towards pre-smoking estimates. The value of psychophysiological indices in relation to drugs of habitual use is questioned.This work was performed at the Department of Psychology. Institute of Psychiatry, London, and supported by the Tobacco Research Council, U.K.     

Regulating Cannabis Social Clubs: A comparative analysis of legal and self-regulatory practices in Spain,Belgium and Uruguay

BackgroundCannabis Social Clubs (CSCs) are a model of non-profit production and distribution of cannabis among a closed circuit of adult cannabis users. CSCs are now operating in several countries around the world, albeit under very different legal regimes and in different socio-political contexts.AimIn this paper we describe and compare the legal framework and the self-regulatory practices of Cannabis Social Clubs in three countries (Spain, Belgium, and Uruguay). The objective of our comparative analysis is to investigate how CSCs operate in each of these countries. To foster discussions about how one might regulate CSCs to promote public health objectives, we conclude this paper with a discussion on the balance between adequate governmental control and self-regulatory competences of CSCs.MethodsThe data used for this analysis stem from independently conducted local studies by the authors in their countries. Although the particular designs of the studies differ, the data in all three countries was collected through similar data collection methods: analysis of (legal and other documents), field visits to the clubs, interviews with staff members, media content analysis.FindingsWe identified a number of similarities and differences among the CSCs’ practices in the three countries. Formal registration as non-profit association seems to be a common standard among CSCs. We found nevertheless great variation in terms of the size of these organisations. Generally, only adult nationals and/or residents are able to join the CSCs, upon the payment of a membership fee. While production seems to be guided by consumption estimates of the members (Spain and Belgium) or by the legal framework (Uruguay), the thresholds applied by the clubs vary significantly across countries. Quality control practices remain an issue in the three settings studied here. The CSCs have developed different arrangements with regards to the distribution of cannabis to their members.ConclusionsBy uncovering the current practices of CSCs in three key settings, this paper contributes to the understanding of the model, which has to some extent been shaped by the self-regulatory efforts of those involved on the ground. We suggest that some of these self-regulatory practices could be accommodated in future regulation in this area, while other aspects of the functioning of the CSCs may require more formal regulation and monitoring. Decisions on this model should also take into account the local context where the clubs have emerged. Finally, the integration of medical supply within this model warrants further attention.     

Cannabis dependence in the San Francisco Family Study: Age of onset of use,DSM-IV symptoms,withdrawal, and heritability

Cannabis is the most widely used illicit drug in the United States, yet the role of genetics in individual symptoms associated with cannabis use disorders has not been evaluated. The purpose of the present set of analyses was to describe the symptomatology and estimate the heritability of DSM-IV criteria/symptoms of cannabis dependence in a large sample of families. Participants were 2524 adults, participating in the University of California San Francisco (UCSF) Family Study of alcoholism. Seventy percent of the sample had ever used cannabis and 13.9% met DSM-IV criteria for cannabis dependence. Younger age at first cannabis use was found to be significantly associated with a shortened survival to becoming cannabis dependent. Although a greater percentage of men met criteria for cannabis dependence, women were found to demonstrate “telescoping” as indexed by a shorter survival time from initial use to dependence as compared to men. A cannabis withdrawal syndrome was identified in users, the primary symptoms of which were nervousness, appetite change, and sleep disturbance. Cannabis use (h² = 0.31) and dependence (h² = 0.20), age at first use, individual DSM-IV criteria for dependence, and cannabis-use associated symptoms of depression, trouble concentrating and paranoia were all found to be heritable. These findings suggest that within this population that cannabis use and dependence, as well as individual cannabis dependence symptoms have a significant heritable component, that cannabis dependence is more likely to occur when use begins during adolescence, and that the cannabis dependence syndrome includes a number of heritable untoward psychiatric side effects including withdrawal.     

The effects of real price and a change in the distribution system on alcohol consumption

Time-series analysis of alcohol consumption data has shown an impact of real price on alcohol consumption in NZ in the decade 1984-96. Beer consumption was reduced by real price increases and wine consumption was increased by real price decreases. By contrast, during this period spirits were price inelastic. A further influence on alcohol consumption was the introduction of wine into grocery stores, which led to a sudden permanent increase in wine consumption 3 months after the legislation came into force. Beer and spirits were not introduced into supermarkets at this time and while there was no effect on beer consumption there was a significant decrease in spirits consumption.     

Definitions of Risky and Problematic Cannabis Use: A Systematic Review

Although cannabis is widely used, it remains unclear which consumption patterns are more likely to produce future consequences (risky/hazardous use) or current damage (problematic/harmful use). This unresolved issue contributes to cannabis public health implications. In order to facilitate further consensus, this review analyzes previously used definitions in the literature. Methods: This systematic review was performed following the PRISMA guidelines. Articles published before October 2015 in the Medline, Scopus–Elsevier, ISI-Web of Knowledge and Cochrane databases and fulfilling a-priori decided criteria were retrieved. Definitions in preselected websites of national and international organizations addressing drug problems were also included. Results: Definitions identified in articles (n = 46) and official websites (n = 3) widely varied from each other. Weekly cannabis use was mostly considered risky. Problematic cannabis use was mostly described with the Cannabis Abuse and Screening Test. Evidence-based definitions as well as information on quantities consumed, time-frames and special considerations for risky groups were very limited. Conclusions: Working on official definitions is highly necessary as criteria used remain incomplete, leading to increased confusion in the field. Recommendations to improve existing definitions are given.     

Substitution and Complementarity of Alcohol and Cannabis: A Review of the Literature

Background: Whether alcohol and cannabis are used as substitutes or complements remains debated, and findings across various disciplines have not been synthesized to date. Objective: This article is a first step towards organizing the interdisciplinary literature on alcohol and cannabis substitution and complementarity. Method: Electronic searches were performed using PubMed and ISI Web of Knowledge. Behavioral studies of humans with “alcohol” (or “ethanol”) and “cannabis” (or “marijuana”) and “complement^*” (or “substitut^*”) in the title or as a keyword were considered. Studies were organized according to sample characteristics (youth, general population, clinical and community-based). These groups were not set a priori, but were informed by the literature review process. Results: Of the 39 studies reviewed, 16 support substitution, ten support complementarity, 12 support neither and one supports both. Results from studies of youth suggest that youth may reduce alcohol in more liberal cannabis environments (substitute), but reduce cannabis in more stringent alcohol environments (complement). Results from the general population suggest that substitution of cannabis for alcohol may occur under more lenient cannabis policies, though cannabis-related laws may affect alcohol use differently across genders and racial groups. Conclusions: Alcohol and cannabis act as both substitutes and complements. Policies aimed at one substance may inadvertently affect consumption of other substances. Future studies should collect fine-grained longitudinal, prospective data from the general population and subgroups of interest, especially in locations likely to legalize cannabis.     

Dissociations between motor timing,motor coordination,and time perception after the administration of alcohol or caffeine

RATIONALE: The impacts of psychoactive drugs on timing have usefully informed theories of timing and its substrates. OBJECTIVES: The objectives of the study are to test the effects of alcohol and caffeine on the explicit timing involved in tapping with the implicit timing observed in the coordinated picking up of an object, and with the temporal discrimination. MATERIALS AND METHODS: Participants in the "alcohol" experiment (N = 16) received placebo, "low" (0.12 g/kg or 0.14 g/kg for women/men, respectively) or "high" (0.37 g/kg or 0.42 g/kg, respectively) doses of alcohol, and those in the "caffeine" experiment (N = 16) received placebo, 200 or 400 mg caffeine. Time production variability was measured by repetitive tapping of specified intervals, and sources of variance attributable to central timer processes and peripheral motor implementation were dissociated. The explicit timing in tapping was compared with the implicit timing in the coordinated picking up of an object. Time perception was measured as discrimination thresholds for intervals of similar duration. Drug effects on reaction time were also measured. RESULTS: For tapping, alcohol significantly increased timer variability, but not motor variability; it did not affect coordination timing in the grip-lift task. Conversely, for time perception, the low dose of alcohol improved temporal discrimination. Caffeine produced no effects on any of the timing tasks, despite significantly reducing reaction times. CONCLUSIONS: The effects of alcohol argue against a common clock process underlying time interval perception and production in the range below 1 s. In contrast to reaction time measures, time perception and time production appear relatively insensitive to caffeine.     

Predictors and consequences of simultaneous alcohol and cannabis use in adolescents

Background/Aims

The simultaneous use of alcohol and cannabis is common among adolescents, but has been little studied. In this study, we examine predictors and consequences of this behavior in a population-based sample of high school students.

Method

Self-reports were obtained from students in Quebec (Canada) followed throughout high school (N = 6589). Logistic regressions were used to test the association between individual, family, and peer-related predictors in grades 7–8 and simultaneous alcohol and cannabis use in grade 10, as well as between simultaneous alcohol and cannabis use in grade 10 and experiencing 3 or more substance-related problems of various types (legal, physical, etc.) in grade 11.

Results

Most predictors in grades 7–8 were associated with simultaneous alcohol and cannabis use in grade 10. Only variables reflecting early-onset substance use involvement — alcohol intoxication, cannabis use, and drug use by close friend(s) — remained predictive in a multivariate model. Simultaneous alcohol and cannabis use was associated with increased substance-related problems in grade 11, above and beyond baseline problems and the concurrent use of the two substances in separate episodes in grade 10.

Conclusions

Simultaneous alcohol and cannabis use 1) is anticipated by multiple psychosocial risk factors which come together with individual and peer substance use in early high school and 2) is independently predictive of subsequent substance-related problems. Providing adolescents with adequate information regarding the potential harm of simultaneous use may be a useful prevention strategy.