Reaching out towards cannabis: approach-bias in heavy cannabis users predicts changes in cannabis use

Aims Repeated drug exposure can lead to an approach‐bias, i.e. the relatively automatically triggered tendencies to approach rather that avoid drug‐related stimuli. Our main aim was to study this approach‐bias in heavy cannabis users with the newly developed cannabis Approach Avoidance Task (cannabis‐AAT) and to investigate the predictive relationship between an approach‐bias for cannabis‐related materials and levels of cannabis use, craving, and the course of cannabis use. Design, settings and participants Cross‐sectional assessment and six‐month follow‐up in 32 heavy cannabis users and 39 non‐using controls. Measurements Approach and avoidance action‐tendencies towards cannabis and neutral images were assessed with the cannabis AAT. During the AAT, participants pulled or pushed a joystick in response to image orientation. To generate additional sense of approach or avoidance, pulling the joystick increased picture size while pushing decreased it. Craving was measured pre‐ and post‐test with the multi‐factorial Marijuana Craving Questionnaire (MCQ). Cannabis use frequencies and levels of dependence were measured at baseline and after a six‐month follow‐up. Findings Heavy cannabis users demonstrated an approach‐bias for cannabis images, as compared to controls. The approach‐bias predicted changes in cannabis use at six‐month follow‐up. The pre‐test MCQ emotionality and expectancy factor were associated negatively with the approach‐bias. No effects were found on levels of cannabis dependence. Conclusions Heavy cannabis users with a strong approach‐bias for cannabis are more likely to increase their cannabis use. This approach‐bias could be used as a predictor of the course of cannabis use to identify individuals at risk from increasing cannabis use.     

Medical use of cannabis: an addiction medicine perspective

The use of cannabis for medical purposes, evident throughout history, has become a topic of increasing interest. Yet on the present medical evidence, cannabis‐based treatments will only be appropriate for a small number of people in specific circumstances. Experience with cannabis as a recreational drug, and with use of psychoactive drugs that are prescribed and abused, should inform harm reduction in the context of medical cannabis.     

The genetic epidemiology of cannabis use, abuse and dependence

AIMS: The genetic etiology of cannabis use, abuse and dependence has elicited significant interest from genetic epidemiologists. METHODS: Genetically informative studies, including family, twin and adoption studies that have examined the role of genetic and environmental influences on the various stages of cannabis involvement, and the genetic relationship between cannabis, licit drugs and other hard drugs, are reviewed. RESULTS: Findings across a number of such studies have indicated that there is a genetic basis to each stage of cannabis involvement although a proportion of the genetic factors influencing individual stages may be specific to that stage. Multivariate analyses that explore the association between cannabis and licit (alcohol and tobacco) as well as hard drugs (e.g. cocaine, opioids), using multiple methodological strategies, suggest the role of common genetic and environmental influences influencing the liability to cannabis and other drug involvement. CONCLUSIONS: The substantial evidence for the heritability of cannabis use, abuse and dependence underscore the importance of linkage and association studies that aim to find genes of etiologic significance.     

Exercise as an adjunctive treatment for cannabis use disorder

Background: Despite cannabis being the most widely used illicit substance in the United States, individuals diagnosed with cannabis use disorder (CUD) have few well-researched, affordable treatment options available to them. Although found to be effective for improving treatment outcomes in other drug populations, exercise is an affordable and highly accessible treatment approach that has not been routinely investigated in cannabis users. Objectives: The aim of this paper is to inform the topic regarding exercise’s potential as an adjunctive treatment for individuals with CUD. Methods: We reviewed the evidence surrounding cannabis use and its current treatment in the United States, explored the rationale for including exercise in the treatment of substance use disorders (SUDs), and in particular, proposed a biological mechanism (i.e., endocannabinoids (eCBs)) that should be examined when utilizing exercise for the treatment of CUD. Results: Cannabis use is widespread and increasing in the United States. Chronic, heavy cannabis use may dysregulate the endogenous cannabinoid system, which has implications for several psychobiological processes that interact with the eCB system such as reward processing and the stress response. Given that exercise is a potent activator of the eCB system, it is mechanistically plausible that exercise could be an optimal method to supplement cessation efforts by reducing psychophysical withdrawal, managing stress, and attenuating drug cravings. Conclusion: We suggest there is a strong behavioral and physiological rationale to design studies which specifically assess the efficacy of exercise, in combination with other therapies, in treating CUD. Moreover, it will be especially important to include the investigation of psychobiological mechanisms (e.g., eCBs, hippocampal volume), which have been associated with both exercise and SUDs, to examine the broader impact of exercise on behavioral and physiological responses to treatment.     

Differentiating new cannabis use from residual urinary cannabinoid excretion in chronic, daily cannabis users

Aims To develop and validate empirically a mathematical model for identifying new cannabis use in chronic, daily cannabis smokers. Design Models were based on urinary creatinine‐normalized (CN) cannabinoid excretion in chronic cannabis smokers. Setting For model development, participants resided on a secure research unit for 30 days. For model validation, participants were abstinent with daily observed urine specimens for 28 days. Participants A total of 48 (model development) and 67 (model validation) daily cannabis smokers were recruited. Measurements All voided urine was collected and analyzed for 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (THCCOOH) by gas chromatography‐mass spectrometry (GCMS; limit of quantification 2.5 ng/ml) and creatinine (mg/ml). Urine THCCOOH was normalized to creatinine, yielding ng/mg CN‐THCCOOH concentrations. Urine concentration ratios were determined from 123 513 specimen pairs collected 2–30 days apart. Findings A mono‐exponential model (with two parameters, initial urine specimen CN‐THCCOOH concentration and time between specimens), based on the Marquardt–Levenberg algorithm, provided a reasonable data fit. Prediction intervals with varying probability levels (80, 90, 95, 99%) provide upper ratio limits for each urine specimen pair. Ratios above these limits suggest cannabis re‐use. Disproportionate numbers of ratios were higher than expected for some participants, prompting development of two additional rules that avoid misidentification of re‐use in participants with unusual CN‐THCCOOH excretion patterns. Conclusions For the first time, a validated model is available to aid in the differentiation of new cannabis use from residual creatinine‐normalized 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (CN‐THCCOOH) excretion in chronic, daily cannabis users. These models are valuable for clinicians, toxicologists and drug treatment staff and work‐place, military and criminal justice drug‐testing programs.     

Hypothalamic-pituitary-adrenal axis reactivity to social stress and adolescent cannabis use: the TRAILS study

Aims To investigate the relationship of life‐time and repeated cannabis use with hypothalamic–pituitary–adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents. Design Adolescents who reported life‐time or repeated cannabis use, life‐time or repeated tobacco use and never use of either cannabis or tobacco were compared with respect to their HPA axis reactivity during the Groningen Social Stress Task (GSST), which was based on the Trier Social Stress Task. Setting A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey (TRAILS) study]. Participants A total of 591 adolescents (51% male) who participated in the GSST, which was an additional measurement during the third assessment wave. Measurements HPA axis stress‐reactivity was indexed by four cortisol samples collected before, during and after the GSST. Furthermore, all adolescents in our study completed self‐reported questionnaires on life‐time and repeated cannabis and tobacco use. Models were adjusted for sex, recent alcohol use, experimental session risk status, socio‐economic status, mood and time of the experimental session. Findings Life‐time cannabis users had significantly lower stress‐reactivity levels when compared to abstainers [odds ratio (OR) = 0.68, confidence interval (CI) = 0.55–0.85, P < 0.01] and life‐time tobacco users (OR = 0.79, CI = 0.64–0.98, P < 0.05). In addition, repeated cannabis users also exhibited lower stress‐reactivity levels when compared to life‐time ever users of either tobacco or cannabis (OR = 0.74, CI = 0.53–0.98, P < 0.05). Conclusions Lower hypothalamic–pituitary–adrenal‐axis stress‐reactivity in adolescents is related specifically to life‐time and repeated cannabis use.