Dysregulation as a correlate of cannabis use and problem use

Unlocking the age-old secrets of reward and substance use

Although substance use is widespread across the lifespan from early adolescence to older adulthood, the prevalence of substance use disorder (SUD) differs between age groups. These age differences in SUD rates necessitate an investigation into how age moderates reward sensitivity, and consequently influences the risks and consequences related to substance use. This theoretical review integrates evidence from the literature to address the dynamic interplay between age and reward in the context of substance use. Overall, increasing evidence demonstrates that age moderates reward sensitivity and underlying reward system neurobiology. Reward sensitivity undergoes a non-linear trajectory across the lifespan. Low levels of reward sensitivity are associated with childhood and late adulthood. In contrast, high levels are associated with early to late adolescence, followed by a decline in the twenties. These fluctuations in reward sensitivity across the lifespan contribute to complex associations with substance use. This lends support to adolescence and young adulthood as vulnerable periods for the risk of subsequent SUD. More empirical research is needed to investigate reward sensitivity during SUD maintenance and recovery. Future research should also involve larger sample sizes and encompass a broader range of age groups, including older adults.

Anhedonia, Apathy, Pleasure, and Effort-Based Decision-Making in Adult and Adolescent Cannabis Users and Controls

BACKGROUND

Cannabis use may be linked with anhedonia and apathy. However, previous studies have shown mixed results, and few have examined the association between cannabis use and specific reward sub-processes. Adolescents may be more vulnerable than adults to harmful effects of cannabis. This study investigated (1) the association between non-acute cannabis use and apathy, anhedonia, pleasure, and effort-based decision-making for reward; and (2) whether these relationships were moderated by age group.

METHODS

We used data from the "CannTeen" study. Participants were 274 adult (26-29 years) and adolescent (16-17 years) cannabis users (1-7 d/wk use in the past 3 months) and gender- and age-matched controls. Anhedonia was measured with the Snaith-Hamilton Pleasure Scale (n = 274), and apathy was measured with the Apathy Evaluation Scale (n = 215). Effort-based decision-making for reward was measured with the Physical Effort task (n = 139), and subjective wanting and liking of rewards was measured with the novel Real Reward Pleasure task (n = 137).

RESULTS

Controls had higher levels of anhedonia than cannabis users (F1,258 = 5.35, P = .02, η p2 = .02). There were no other significant effects of user-group and no significant user-group*age-group interactions. Null findings were supported by post hoc Bayesian analyses.

CONCLUSION

Our results suggest that cannabis use at a frequency of 3 to 4 d/wk is not associated with apathy, effort-based decision-making for reward, reward wanting, or reward liking in adults or adolescents. Cannabis users had lower anhedonia than controls, albeit at a small effect size. These findings are not consistent with the hypothesis that non-acute cannabis use is associated with amotivation.

Initial evaluation of domain-specific episodic future thinking on delay discounting and cannabis use

Episodic Future Thinking (EFT), mental simulation of personally relevant and positive future events, may modulate delay discounting (DD) in cannabis users. Whether EFT impacts cannabis use, whether DD mediates this effect, and whether EFT can be enhanced by prompting future events across specific life domains is unknown. Active, adult cannabis users (n = 90) recruited from Amazon mTurk and Qualtrics Panels were administered an Episodic Specificity Induction (ESI) to enhance quality of imagined events before being randomized to EFT, domain-specific-EFT (DS-EFT), or Episodic Recent Thinking (ERT). All participants created four, positive life events; DS-EFT participants imagined social, leisure, health, and financial events. Event-quality ratings were assessed (e.g., enjoyment). DD was assessed at baseline (Day 1), post-intervention (Days 2-4), and follow-up (Days 9-12). Cannabis use was assessed at baseline and follow-up. Differences in change in days and grams of cannabis use between conditions and mediation of changes in use by DD were examined. No differences in DD were observed between conditions. DS-EFT, but not EFT, showed significantly greater reductions in grams (d = .54) and days of cannabis use (d = .50) than ERT. DS-EFT and EFT demonstrated significantly greater event-quality ratings than ERT (ds > .55). EFT-based interventions showed potential for reducing cannabis use. Unexpectedly, effects on DD did not mediate this effect. Further testing with larger samples of cannabis users is needed to better understand EFT's mechanisms of action and determine optimal implementation strategies. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Why Use Cannabis? Examining Motives for Cannabis Use in Individuals with Anxiety Disorders

This study examined cannabis use motives in individuals with anxiety disorders and compared motives between infrequent and frequent cannabis users. It was hypothesised that coping motives would be endorsed at a significantly higher rate than other motives, and that frequent cannabis users would endorse coping motives significantly more than infrequent users. Participants were 144 adults seeking clinical services for anxiety disorders who reported using cannabis. Cannabis use was categorized by infrequent (n = 54) and frequent (n = 90) use. Anxiety symptoms were assessed and deemed clinically significant. Participants completed measures of cannabis use motives, cannabis use patterns, and cannabis use disorder symptoms, cross-sectionally. Cannabis use motives were examined for the entire sample and compared between frequent and infrequent users. In general, cannabis users endorsed coping (i.e., use for managing distress) and enhancement (i.e., use for fun, pleasant feeling, or the high) motives at equal rates (p = .265) and more than other motives (p < .001). Frequent users reported using cannabis for coping and expansion motives (i.e., use to change one's thinking) significantly more than infrequent users. These results indicate that individuals with anxiety disorders use cannabis for various reasons, some of which may not be directly related to their mental health symptoms. Future research is needed to compare motives for cannabis use in those with anxiety disorders, other mental health populations, and the general population, as well as examine motives for cannabis use within specific anxiety disorders.

Age differences in the behavioural economics of cannabis use: Do adolescents and adults differ on demand for cannabis and discounting of future reward?

BACKGROUND

Adolescence is a period of psychological and neural development in which harms associated with cannabis use may be heightened. We hypothesised that adolescent who use cannabis (adolescentsWUC) would have steeper delay discounting (preference for immediate over future rewards) and greater demand (relative valuation) for cannabis than adults who use cannabis (adultsWUC).

METHODS

This cross-sectional study, part of the 'CannTeen' project, compared adultsWUC (n = 71, 26-29 years old) and adolescentsWUC (n = 76, 16-17 years old), and gender- and age-matched adolescent (n = 63) and adult (n = 64) controls. AdolescentsWUC and adultsWUC used cannabis 1-7 days/week and were matched on cannabis use frequency (4 days/week). The Monetary Choice Questionnaire assessed delay discounting. A modified Marijuana Purchase Task (MPT) assessed cannabis demand in adolescentsWUC and adultsWUC. The MPT yielded five indices: intensity (amount of cannabis used at zero cost), O_max (total peak expenditure), P_max (price at peak expenditure), breakpoint (cost at which cannabis demand is suppressed to zero) and elasticity (degree to which cannabis use decreases with increasing price). Analyses were adjusted for covariates of gender, socioeconomic status, other illicit drug use.

RESULTS

Both adolescentsWUC and adultsWUC had steeper delay discounting than controls (F, (1,254)= 9.13, p = 0.003, η_p²= 0.04), with no significant age effect or interaction. AdolescentsWUC showed higher intensity (F, (1,138)= 9.76, p = 0.002, η_p²= 0.07) and lower elasticity (F, (1,138)= 15.25, p < 0.001, η_p²= 0.10) than adultsWUC. There were no significant differences in P_max, O_max or breakpoint.

CONCLUSION

Individuals who use cannabis prefer immediate rewards more than controls. AdolescentsWUC, compared to adultsWUC, may be in a high-risk category with diminished sensitivity to cannabis price increases and a greater consumption of cannabis when it is free.

Additive roles of tobacco and cannabis co-use in relation to delay discounting in a sample of heavy drinkers

RATIONALE

Alcohol use disorder (AUD) is associated with steeper delay discounting rates; however, it is unknown whether substance co-use, particularly cannabis use, has an additive effect on discounting rates among heavy drinkers. Furthermore, it is unclear whether substance co-use and delay discounting are independently associated with AUD severity.

OBJECTIVES

The purpose of this study was to determine whether alcohol, tobacco, and cannabis co-use impacts delay discounting rates. We also sought to determine whether substance co-use and delay discounting were associated with AUD symptom counts.

METHODS

The study sample was culled from several human laboratory studies and consisted of 483 heavy drinking individuals who completed a baseline visit (prior to experimental procedures). Participants were divided into groups based on self-reported alcohol, tobacco, and cannabis use during the past 30 days: alcohol only (n = 184), alcohol + cigarettes (n = 89), alcohol + cannabis (n = 82), and tri-use (n = 128). We examined discounting rates across the 4 groups and used multiple linear regression to test whether co-use and delay discounting were associated with AUD symptoms.

RESULTS

After adjusting for covariates, individuals in the alcohol + cannabis group and the tri-use group had steeper discounting rates relative to the alcohol-only group. In addition, tri-use and delay discounting rates were independently correlated with a greater number of AUD symptoms.

CONCLUSIONS

Delay discounting rates were significantly greater among subgroups reporting cannabis use providing partial support for an additive effect, while also highlighting the importance of co-use substance type. Both tri-use and delay discounting were associated with greater AUD severity, which may provide relevant intervention targets.

Impulsivity Relates to Multi-Trial Choice Strategy in Probabilistic Reversal Learning

Impulsivity is defined as a trait-like tendency to engage in rash actions that are poorly thought out or expressed in an untimely manner. Previous research has found that impulsivity relates to deficits in decision making, in particular when it necessitates executive control or reward outcomes. Reinforcement learning (RL) relies on the ability to integrate reward or punishment outcomes to make good decisions, and has recently been shown to often recruit executive function; as such, it is unsurprising that impulsivity has been studied in the context of RL. However, how impulsivity relates to the mechanisms of RL remains unclear. We aimed to investigate the relationship between impulsivity and learning in a reward-driven learning task with probabilistic feedback and reversal known to recruit executive function. Based on prior literature in clinical populations, we predicted that higher impulsivity would be associated with poorer performance on the task, driven by more frequent switching following unrewarded outcomes. Our results did not support this prediction, but more advanced, trial-history dependent analyses revealed specific effects of impulsivity on switching behavior following consecutive unrewarded trials. Computational modeling captured group-level behavior, but not impulsivity results. Our results support previous findings highlighting the importance of sensitivity to negative outcomes in understanding how impulsivity relates to learning, but indicate that this may stem from more complex strategies than usually considered in computational models of learning. This should be an important target for future research.

A systematic review and meta-analysis of delay discounting and cannabis use

Delay discounting reflects the systematic reduction in the value of a consequence by delay to delivery. Theoretical and empirical work suggests that delay discounting is a key behavioral mechanism underlying substance use disorder. Existing work on cannabis use, however, is mixed with many studies reporting null results. The purpose of this review was to provide an in-depth assessment of the association between delay discounting and cannabis use. We conducted metaregression analyses to determine the omnibus correlation between delay discounting and cannabis use, and to evaluate task-based and sample-based moderators. Studies included evaluated an association between delay discounting and cannabis quantity-frequency or severity measures in human participants (27 studies, 61 effect sizes, 24,782 participants). A robust variance estimation method was used to account for dependence among effect sizes. A significant, but small, omnibus effect was observed (r = .082) in which greater cannabis use frequency or severity was associated with greater discounting. Incentive structure and outcome type were each significant moderators in a multiple moderator model such that incentivized tasks correlated with severity measures showed stronger associations (r = .234) than hypothetical tasks correlated with quantity-frequency measures (r = .029). Comparisons to historic effect size data supported the hypothesis that, at present, the relationship between cannabis use and delay discounting appears empirically smaller than for other substances. Future work should explore theoretical rationales explaining this modest relationship involving cannabis use and delay discounting, such as reflecting the smaller magnitude of perceived long-term clinical outcomes associated with cannabis compared to other substances. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Apathy and Anhedonia in Adult and Adolescent Cannabis Users and Controls Before and During the COVID-19 Pandemic Lockdown

BACKGROUND

COVID-19 lockdown measures have caused severe disruptions to work and education and prevented people from engaging in many rewarding activities. Cannabis users may be especially vulnerable, having been previously shown to have higher levels of apathy and anhedonia than non-users.

METHODS

In this survey study, we measured apathy and anhedonia, before and after lockdown measures were implemented, in n = 256 adult and n = 200 adolescent cannabis users and n = 170 adult and n = 172 adolescent controls. Scores on the Apathy Evaluation Scale (AES) and Snaith-Hamilton Pleasure Scale (SHAPS) were investigated with mixed-measures ANCOVA, with factors user group, age group, and time, controlling for depression, anxiety, and other drug use.

RESULTS

Adolescent cannabis users had significantly higher SHAPS scores before lockdown, indicative of greater anhedonia, compared with adolescent controls (P = .03, η p2 = .013). Contrastingly, adult users had significantly lower scores on both the SHAPS (P < .001, η p2 = .030) and AES (P < .001, η p2 = .048) after lockdown compared with adult controls. Scores on both scales increased during lockdown across groups, and this increase was significantly smaller for cannabis users (AES: P = .001, η p2 = .014; SHAPS: P = .01, η p2 = .008). Exploratory analyses revealed that dependent cannabis users had significantly higher scores overall (AES: P < .001, η p2 = .037; SHAPS: P < .001, η p2 = .029) and a larger increase in scores (AES: P = .04, η p2 =.010; SHAPS: P = .04, η p2 = .010), compared with non-dependent users.

CONCLUSIONS

Our results suggest that adolescents and adults have differential associations between cannabis use as well as apathy and anhedonia. Within users, dependence may be associated with higher levels of apathy and anhedonia regardless of age and a greater increase in levels during the COVID-19 lockdown.

The acute and non-acute effects of cannabis on reward processing: A systematic review

Cannabis use has historically been thought to cause amotivation, but the relationship between cannabis and apathy, anhedonia, and reward processing remains poorly characterised. In this systematic review, we evaluated whether cannabis exposure acutely and/or non-acutely was associated with altered reward processing using questionnaire, behavioural, or functional neuroimaging measures. Questionnaire studies demonstrated greater anhedonia in adolescent cannabis users, and some indication of greater apathy in young adult cannabis users. Behavioural studies yielded some evidence of reduced reward learning in adolescent cannabis users, though there were too few studies in this category for reliable conclusions. Finally, longitudinal and acute functional neuroimaging studies showed an association between cannabis and blunted neural responses to reward, which did not emerge consistently in cross-sectional studies. The current results suggest that cannabis use is associated with specific impairments in reward and motivation. Future large-scale, longitudinal studies which use multiple behavioural and neuroimaging measures of reward processing may further clarify the impact of cannabis use on motivational and reward processes, and neural networks.

The Clinical Assessment of Vaping Exposure

: Vaping, the inhalation of a nicotine or tetrahydrocannabinol (THC), cannabidiol (CBD), or non-drug infused solution delivered by vaping devices, is a growing phenomenon across many segments of the US population. Complications associated with vaping are newly emerging and relatively unstudied; little guidance exists on how clinicians may best elicit information related to vaping practices and associated medical problems. This publication, therefore, provides physicians and other treatment clinicians with direction for obtaining the medical history that can guide clinical decision-making for patients at risk for adverse effects associated with vaping.

Down and High: Reflections Regarding Depression and Cannabis

In light of the recent changes in the legal status of cannabis in Canada, the understanding of the potential impact of the use of cannabis by individuals suffering from depression is increasingly considered as being important. It is fundamental that we look into the existing literature to examine the influence of cannabis on psychiatric conditions, including mood disorders. In this article, we will explore the relationship that exists between depression and cannabis. We will examine the impact of cannabis on the onset and course of depression, and its treatment. We have undertaken a wide-ranging review of the literature in order to address these questions. The evidence from longitudinal studies suggest that there is a bidirectional relationship between cannabis use and depression, such that cannabis use increases the risk for depression and vice-versa. This risk is possibly higher in heavy users having initiated their consumption in early adolescence. Clinical evidence also suggests that cannabis use is associated with a worse prognosis in individuals with major depressive disorder. The link with suicide remains controversial. Moreover, there is insufficient data to determine the impact of cannabis use on cognition in individuals with major depression disorder. Preliminary evidence suggesting that the endogenous cannabinoid system is involved in the pathophysiology of depression. This will need to be confirmed in future positron emission tomography studies. Randomized controlled trials are needed to investigate the potential efficacy of motivational interviewing and/or cognitive behavioral therapy for the treatment of cannabis use disorder in individuals with major depressive major disorder. Finally, although there is preclinical evidence suggesting that cannabidiol has antidepressant properties, randomized controlled trials will need to properly investigate this possibility in humans.

Which came first: Cannabis use or deficits in impulse control?

Impulse control deficits are often found to co-occur with substance use disorders (SUDs). On the one hand, it is well known that chronic intake of drugs of abuse remodels the brain with significant consequences for a range of cognitive behaviors. On the other hand, individual variation in impulse control may contribute to differences in susceptibility to SUDs. Both of these relationships have been described, thus leading to a "chicken or the egg" debate which remains to be fully resolved. Does impulsivity precede drug use or does it manifest as a function of problematic drug usage? The link between impulsivity and SUDs has been most strongly established for cocaine and alcohol use disorders using both preclinical models and clinical data. Much less is known about the potential link between impulsivity and cannabis use disorder (CUD) or the directionality of this relationship. The initiation of cannabis use occurs most often during adolescence prior to the brain's maturation, which is recognized as a critical period of development. The long-term effects of chronic cannabis use on the brain and behavior have started to be explored. In this review we will summarize these observations, especially as they pertain to the relationship between impulsivity and CUD, from both a psychological and biological perspective. We will discuss impulsivity as a multi-dimensional construct and attempt to reconcile the results obtained across modalities. Finally, we will discuss possible avenues for future research with emerging longitudinal data.

Sifting through the weeds: Relationships between cannabis use frequency measures and delay discounting

BACKGROUND

Delay Discounting (DD) relates to more frequent cannabis use, but results are variable, potentially because of variations in whether integrated or single-item measures are used, and whether the timeframe of measures is narrow or broad. Explicating the relationship between DD and cannabis use may result from comparing use indices that vary on these characteristics.

METHODS

This online study of current cannabis users (n = 1,800) assessed DD and three cannabis use frequency items: number of days of use in the past month, times used per day, and weekly-monthly use. A fourth index derived with Latent Class Analysis (LCA) integrated days per month and times per day to try to better characterize frequency patterns. Effect sizes reflecting relations between cannabis use frequency indices and DD were compared.

RESULTS

Three frequency classes emerged from the LCA (Low-Moderate-High). DD was significantly associated with times per day (r = 0.11, d = 0.21), days of use (r = 0.09, d = 0.18), and the LCA index (r = 0.06, d = 0.13), but not weekly-monthly use (r = 0.04, d = 0.09). Times per day was more strongly related to DD than LCA classes (p < 0.01) and weekly-monthly use (p < 0.05), but not days of use (p = 0.66). Days of use exhibited a stronger relationship with DD than weekly-monthly use (p < 0.001), but not LCA classes (p = 0.06).

CONCLUSIONS

Cannabis use frequency measures with narrower timeframes may demonstrate stronger positive relationships to DD. The LCA index did not improve the relationship between frequency and DD, potentially because of shared variance between use days and times per day. Specific characteristics of cannabis use frequency may be particularly indicative of excessive DD.

Examining motivational pathways from adult attention-deficit/hyperactivity disorder symptoms to cannabis use: Results from a prospective study of veterans

Objective: Attention-deficit/hyperactivity disorder (ADHD) is linked prospectively to cannabis; however, no study has examined mechanisms underlying this comorbidity. We examined 5 cannabis motives (i.e., coping with negative affect, sleep, social anxiety, perceived low risk of cannabis, and altered perception) as mediators of the prospective ADHD-cannabis relation. Method: Veterans reporting lifetime cannabis use (N = 361; 93% male; 80% White) completed three semiannual assessments. Prospective mediation models using structural equation modeling analyzed the indirect effects of baseline ADHD symptoms on 12-month cannabis use and problems via each motive at 6 months. Zero-inflated negative binomial models were employed for both manifest outcomes and ADHD symptoms and motives were each modeled as 1-factor latent variables. Results: Sleep motives was a robust mediator for cannabis use frequency in single mediator models and was marginally significant when examined simultaneously with other motives after accounting for baseline cannabis use, demographics, other substance use, and other psychopathology. Coping with negative affect was the only significant mediator of ADHD symptoms and subsequent cannabis problem severity. Conclusion: Among veterans with ADHD symptoms, sleep disturbance is a salient motive for cannabis use, whereas coping with negative affect is a proximal predictor of cannabis problems. Findings support addressing sleep disturbance in adults with ADHD symptoms and converge with extant literature demonstrating robust associations between coping motives and substance use problems. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Greater delay discounting and cannabis coping motives are associated with more frequent cannabis use in a large sample of adult cannabis users

BACKGROUND

Self-regulation deficits expressed through a decreased ability to value future rewards (delay discounting (DD)) and impaired emotion regulation (negative urgency (NU), cannabis coping motives (CCM), and anxiety sensitivity (AS)) relate to more frequent or problematic cannabis use. However, there is a need to better understand how self-regulation and emotion regulation constructs reflect competition between deliberative and reactive systems that drive individual differences in cannabis use patterns. Further, few studies assess frequency of cannabis use within and across days of use, which may obscure differentiation of individual differences.

METHODS

In a large national sample of 2545 cannabis users, Latent Class Analysis was used to derive participant sub-classes based on two frequency indices, self-reported cannabis use days and times cannabis was used per day. Three classes emerged: Low (1-9 days/month, 1 time/day; 23 %), moderate (10-29 days/month, 2-3 times/day; 41 %), and high (30 days/month, ≥4 times/day; 36 %). Relationships among frequency classes and emotional regulation and impulsivity were assessed with a multinomial logistic regression.

RESULTS

Higher frequency use was associated with greater DD (χ2 = 6.0, p = .05), greater CCM (χ2 = 73.3, p < .001), and lower cognitive AS (χ2 = 12.1, p = .002), when controlling for demographics, tobacco use, and number of cannabis administration methods. Frequency class and NU were not significantly associated.

CONCLUSIONS

Identifying meaningful patterns of cannabis use may improve our understanding of individual differences that increase risk of frequent or problematic cannabis use. Excessive delay discounting and using cannabis to cope with negative affect may be relevant targets for treatments designed to reduce cannabis use.

A web-based episodic specificity and future thinking session modulates delay discounting in cannabis users

Episodic future thinking (EFT), a brief intervention involving mental simulation of positive future events, improves delay discounting (DD) in nicotine and alcohol dependent individuals. This study is the first to assess effects of a single-session, online episodic training (ET) on constructs that might impact cannabis use and cannabis use disorder. A sample of 200 active cannabis users recruited via Amazon Mechanical Turk were randomized to an EFT group (n = 102) or an episodic recent thinking control group (ERT; n = 98). A novel episodic specificity induction (ES) was included to enhance quality of episodic thinking for the ET group, and an ES attention control was provided to the ERT group (control training group; CT). Quality and manipulation ratings of event excitement, vividness, importance, and enjoyment of trainings were collected in addition to DD tasks (gains and losses) and readiness to change cannabis use. The ET group reported higher overall quality and manipulation ratings than did the CT group (p < .001, d = 0.79). DD of gains was lower in the ET relative to those of the CT group after controlling for relevant variables (p = .003, d = 0.48), unlike DD of losses (p = .50, d = 0.11). The ET group showed larger pre/post increases in readiness to change, but they were not statistically significant (p = .069, d = 0.26). These effects, following a session of online ET, suggests that ET may positively impact factors related to reduction in cannabis use. Differential effects of EFT and ES components on DD and the development of ET as an adjunctive mHealth intervention targeting reduction in cannabis use appears warranted. (PsycInfo Database Record (c) 2020 APA, all rights reserved).