Cannabis use and anxiety in daily life: a naturalistic investigation in a non-clinical population

Cannabinoid and Serotonergic Systems: Unraveling the Pathogenetic Mechanisms of Stress-Induced Analgesia

The perception of "stress" triggers many physiological and behavioral responses, collectively called the stress response. Such a complex process allows for coping with stress and also triggers severe pathology. Because of the multidirectional effect of stress on the body, multiple systems participate in its pathogenesis, with the endogenous cannabinoid and the serotoninergic ones among them. These two systems also take part in the pain perception decrease, known as stress-induced analgesia (SIA), which can then be taken as an indirect indicator of the stress response. The aim of our study was to study the changes in cold SIA (c-SIA) resulting from the exogenous activation of cannabinoid receptor type 1 (CB1) and 5-hydroxytryptamine (5-HT, serotonin) receptor type 1A (5-HT1A). Various combinations of agonists and/or antagonists of CB1 and 5-HT1A, before or after 1 h of cold exposure, were applied, since we presumed that the exogenous activation of the receptors before the cold exposure would influence the pathogenesis of the stress response, while their activation after the stressful trigger would influence the later development. Our results show that the serotonergic system "maintained" c-SIA in the pre-stress treatment, while the cannabinoids' modulative effect was more prominent in the post-stress treatment. Here, we show the interactions of the two systems in the stress response. The interpretation and understanding of the mechanisms of interaction between CB1 and 5-HT1A may provide information for the prevention and control of adverse stress effects, as well as suggest interesting directions for the development of targeted interventions for the control of specific body responses.

Cannabis and Anxiety: A Critical Review

Introduction

Cannabis has been reported to have both anxiogenic and anxiolytic effects. Habitual cannabis use has been associated with anxiety disorders (AD). The causal pathways and mechanisms underlying the association between cannabis use (CU)/cannabis use disorder (CUD) and anxiety remain unclear. We examined the literature via a systematic review to investigate the link between cannabis and anxiety. The hypotheses studied include causality, the common factor theory, and the self-medication hypothesis.

Methods

Critical systematic review of published literature examining the relationship of CU/CUD to AD or state-anxiety, including case reports, literature reviews, observational studies, and preclinical and clinical studies. A systematic MEDline search was conducted of terms including: [anxiety], [anxiogenic], [anxiolytic], [PTSD], [OCD], [GAD], [cannabis], [marijuana], [tetrahydrocannabinol], [THC].

Results

While several case-control and cohort studies have reported no correlation between CU/CUD and AD or state anxiety (N = 5), other cross-sectional, and longitudinal studies report significant relationships (N = 20). Meta-analysis supports anxiety correlating with CU (N = 15 studies, OR = 1.24, 95% CI: 1.06-1.45, p = 0.006) or CUD (N = 13 studies, OR = 1.68, 95% CI: 1.23-2.31, p = 0.001). PATH analysis identifies the self-medication hypothesis (N = 8) as the model that best explains the association between CU/CUD and AD or state-anxiety. Despite the support of multiple large cohort studies, causal interpretations (N = 17) are less plausible, while the common factor theory (N = 5), stress-misattribution hypothesis, and reciprocal feedback theory lack substantial evidential support.

Conclusion

The association between cannabis and anxiety is best explained by anxiety predisposing individuals toward CU as a method of self-medication. A causal relationship in which CU causes AD incidence is less likely despite multiple longitudinal studies suggesting so.

Differences in internalizing symptoms between those with and without Cannabis Use Disorder among HBCU undergraduate students

OBJECTIVE

To determine the differences in internalizing symptoms between those who met criteria for Cannabis Use Disorder (CUD) and those who did not in young adults attending a Historically Black College or University (HBCU).

PARTICIPANTS

The sample included 619 undergraduate students, with 110 (18%) who met criteria for CUD.

METHODS

Participants completed an online survey, which included demographic, anxious and depressive symptomatology, and substance use assessment.

RESULTS

Those who met CUD criteria reported more depressive symptoms (M = 22.83 ± 10.74) and anxiety symptoms (M = 45.70 ± 12.82) than their non-CUD counterparts (M = 19.17 ± 10.58; M = 40.57 ± 14.11, respectively).

CONCLUSION

Differences between those who met criteria for CUD and those who did not are consistent with previous literature and may aid in characterizing internalizing behaviors in HBCU students with CUD. Future research should examine the subgroups that may cycle through withdrawal symptoms, despite not having severe CUD. This subgroup may be at higher risk for psychopathology than their severe counterparts.

Predicting quantity of cannabis smoked in daily life: An exploratory study using machine learning

BACKGROUND

Cannabis use is prevalent in the United States and is associated with a host of negative consequences. Importantly, a robust indicator of negative consequences is the amount of cannabis consumed.

METHODS

Data were obtained from fifty-two adult, regular cannabis flower users (3+ times per week) recruited from the community; participants completed multiple ecological momentary assessment (EMA) surveys each day for 14 days. In this exploratory study, we used various machine learning algorithms to build models to predict the amount of cannabis smoked since participants' last report including forty-three EMA measures of mood, impulsivity, pain, alcohol use, cigarette use, craving, cannabis potency, cannabis use motivation, subjective effects of cannabis, social context, and location in daily life.

RESULTS

Our best-fitting model (Gradient Boosted Trees; 71.15% accuracy, 72.46% precision) found that affects, subjective effects of cannabis, and cannabis use motives were among the best predictors of cannabis use amount in daily life. The social context of being with others, and particularly with a partner or friend, was moderately weighted in the final prediction model, but contextual items reflecting location were not strongly weighted in the final prediction model, the one exception being not at work.

CONCLUSIONS

Machine learning approaches can help identify additional environmental and psychological phenomena that may be clinically-relevant to cannabis use.

Association between affect and cannabis use varies by social context

BACKGROUND

Cannabis use is rising globally, underscoring the importance of understanding contextual factors related to cannabis use. Although much work has retrospectively examined cannabis use patterns and effects, fewer studies have evaluated cannabis use in natural environments.

METHODS

The present study used ecological momentary assessment (EMA) to examine the subjective experience of cannabis use (i.e., positive and negative affect) and how cannabis' mood effects are modified by the social context, defined as being alone or with others, in which use occurs. Associations between cannabis' mood effects and cannabis use disorder symptomatology were additionally examined. Participants (N = 200) completed baseline assessments and two 7-day waves of EMA data collection. Mixed-effects models examined between- and within-subject effects for positive and negative affect at cannabis use and nonuse times and interactions between cannabis use and social context.

RESULTS

Positive affect was elevated at cannabis use times, compared to nonuse times, regardless of social context. The relationship between cannabis use and negative affect was moderated by social context, such that negative affect was elevated at cannabis use times when participants were alone and reduced at cannabis use times when participants were with others. Higher levels of cannabis use disorder symptomatology and cannabis use frequency were both associated with lower negative affect at cannabis use times.

CONCLUSIONS

These results suggest that elevated positive affect is consistent across cannabis use times regardless of social context, but negative affect may vary more by the presence of others.

Posttraumatic stress disorder, sleep and medical cannabis treatment: A daily diary study

Despite increasing use of Medical Cannabis (MC) among posttraumatic stress disorder (PTSD) patients, research is lacking on how MC treatment relates to PTSD symptomatology, in particular sleep disturbances. This study examines the time gap between MC use and sleep onset and its association with (1) number of awakenings throughout the night, (2) early awakenings, (3) nightmares. Each morning over a two week period, 77 licensed MC patients suffering from PTSD reported on the timing of previous night MC use and sleep disturbances. Within-person analyses found that shorter time gaps between previous night MC use and sleep start time was associated with lower likelihood of experiencing nightmares throughout the night, but it was not associated with nightly awakenings or waking up too early. Between-person analyses showed that individuals who used MC products with higher CBD concentrations reported fewer early awakenings. These preliminary results indicate that future research should test causal relations between MC use and sleep problems in PTSD patients. Future research is warranted in order to explore causal relationships between MC use, nightmares and insomnia in PTSD patients.

Cannabis use as a predictor and outcome of positive and negative affect in college students: An ecological momentary assessment study

BACKGROUND

Reinforcement models identify negative affect (NA) and positive affect (PA) to be important momentary determinants and outcomes of cannabis use. Sensitization and allostatic models further suggest that these mood-cannabis associations are stronger among individuals with more cannabis-related problems. Despite this theoretical background and the fact that cannabis is commonly used for its mood-enhancing effects among college students, surprisingly, little is known about the momentary associations between mood and cannabis use in this population.

AIMS

To examine the associations between (a) momentary within-person variations in NA (worried, stressed, nervous) and PA (happy, enthusiastic, proud, excited) and intention to use cannabis within the next hour, (b) the within-person variations in time elapsed since last cannabis use, amount used and momentary NA and PA, and (c) to test whether cannabis-related problems moderate the stated associations.

METHOD

Eighty, more-than-weekly, cannabis using students at the University of Amsterdam reported on cannabis use, NA and PA three times daily for 14 consecutive days. Mixed-effects models were performed to analyze the dataset.

RESULTS

Within-persons, relatively high PA and low NA were associated with a higher likelihood of intending to use cannabis. Within-persons, more recent and greater amounts of cannabis use were associated with relatively high PA. More recent cannabis use was associated with relatively low NA. Cannabis-related problems did not moderate the associations.

CONCLUSIONS

While recent cannabis use related to higher PA and lower NA, high PA but low NA preceded use, supporting positive reinforcement rather than negative reinforcement in this college sample of regular cannabis users.

The Effect of Momentary Affect on Substance Use among Young Adults Who Experience Homelessness

IntroductionLittle is known about the momentary patterns and predictors of substance use among young adults who experience homelessness. To enhance understanding of substance use patterns, smartphone-based ecological momentary assessment (EMA) was utilized to examine the real-time association between affect and substance use. Methods: 251 young adults (aged 18-27) with history of homelessness were recruited from supportive housing programs and drop-in facilities in Los Angeles. Exploratory factor analysis was used to examine the latent structure of positive and negative affective states and mixed-effects logistic regression models were completed separately for both the full remaining sample (n = 227) and a subsample of alcohol or cannabis users (n = 145) to evaluate whether positive or negative affect predicted lead, recent, or lagged substance use. Results: Greater positive affect within-person was associated with greater odds of alcohol or cannabis use within the past two hours, and participants who reported feeling more negative than their peers experienced greater odds of reporting use within the past 4 h and the following two hours. Conclusion: Results suggest that individuals experience a heightened positive mood compared to their own average mood, concurrently or immediately after engaging in alcohol or cannabis use. Heightened positive mood might be an anticipatory effect of drinking or cannabis use. Future research should consider a longer study period to capture multiple drinking or drug use events over a longer period and consider more environmental exposures that may influence the frequency or intensity of substance use.

Cannabis and Alcohol Use and Their Associations with Sleep: A Daily Diary Investigation of Single-Use and Co-Use in College Students

Introduction: Sleep continuity problems are widespread among college students and may be influenced by single-use and co-use of alcohol and cannabis. We examined the within-person associations of alcohol and cannabis use with subsequent sleep experiences in the everyday life of college students. Materials and Methods: A sample of 80 college students reported prior-night alcohol and cannabis use and sleep experiences for 14 consecutive days. Mixed-effects models examined the within-person relationships between alcohol and cannabis use (single- and co-use) and subsequent (1) sleep-onset latency, (2) total sleep time, (3) number of awakenings, and (4) early awakenings that night. Results: Compared to no-use evenings, alcohol and cannabis, used separately or together (co-use), were associated with shorter sleep-onset latency and longer total sleep time. Students reported more nightly awakenings after alcohol-only use compared to no-use and after co-use, and they reported fewer early awakenings after no-use and co-use. Conclusions: In line with previous experimental findings, we found that alcohol and cannabis use in the everyday life of college students were associated with sleep-inducing effects, and that alcohol use was associated with disturbed sleep continuity. The results suggest that cannabis may curb alcohol's detrimental effect on the number of awakenings and may reduce the incidence of early awakenings. Yet, due to lack of control for potentially important confounders (e.g., quantity of cannabis/alcohol consumed, withdrawal) the current results may be best seen as preliminary and further research is needed before causal inferences can be reached.

Cannabis Use, Cannabis Use Disorder, and Comorbid Psychiatric Illness: A Narrative Review

BACKGROUND

The landscape of attitudes, legal status and patterns of use of cannabis is rapidly changing in the United States and elsewhere. Therefore, the primary aim of this narrative review is to provide a concise overview of the literature on the comorbidity of cannabis use and cannabis use disorder (CUD) with other substance use and psychiatric disorders, and to use this information to accurately guide future directions for the field.

METHODS

A literature review of PubMed was conducted for studies relating to cannabis use, CUD, and a co-occurring psychiatric disorder. To provide an overview of representative data, the literature review focused on national-level, population-based work from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) and National Survey on Drug Use and Health (NSDUH) surveys. Considering rapidly changing cannabis laws, recent (past five-year) studies were addressed.

RESULTS

A strong body of literature shows associations between cannabis use and CUD with other drug use, psychosis, mood disorders, anxiety disorders, and personality disorders. The strongest evidence of a potential causal relationship exists between cannabis use and psychotic disorders. While some evidence shows potential directionality between cannabis use and mood and anxiety disorders, results are inconsistent. Studies have established higher rates of CUD among those with personality disorders, but little about the specifics of this relationship is understood.

CONCLUSIONS

Although the general population in the United States increasingly perceives cannabis to be a harmless substance, empirical evidence shows that cannabis use is associated both with CUD and comorbid psychiatric illness. However, there is mixed evidence regarding the role of cannabis in the etiology, course, and prognosis of a co-occurring disorder across all categories of psychiatric disorders. Future research should expand on the existing body of literature with representative, longitudinal data, in order to better understand the acute and long-term effects of cannabis on comorbid psychiatric illness.

CANreduce 2.0: Reduzierung des Cannabiskonsums unter Berücksichtigung von psychischen Komorbiditäten wie der Generalisierten Angststörung – Zwei Fliegen auf einen Schlag?

Ziel der Studie Zahlreiche Studien weisen auf ein breites Spektrum häufig gleichzeitig auftretender psychischer Störungen wie jene der Generalisierten Angststörung bei der Behandlung von Personen mit Cannabiskonsumstörungen hin (GAD). Bisherige Internet-basierte Studien konnten zwar vereinzelt die Reduktion von Cannabiskonsum zeigen, berücksichtigten aber keine komorbide Störungen. Ziel des E-Coach gestützten Online-Selbsthilfeprogramm CANreduce 2.0 ist die Reduzierung des Cannabiskonsums und der gegebenenfalls vorhandenen GAD.

Methodik Sekundäranalyse der in der Allgemeinbevölkerung rekrutierten Cannabiskonsumierenden der CANreduce 2.0 Studie der beiden aktiven Interventionsgruppen (N=367). Für die Analysen wurden diese Teilnehmende aufgrund ihres erreichten Symptomatik-Wertes der General Anxiety Disorder Scale (GAD-7) in 4 Gruppen eingeteilt: Minimale (GAD-7 Werte: 0–4; N=102), Milde (5–9; N=151), Moderate (10–14; N=78) und Schwere (15–21; N=36) Angststörung und anschliessend ihre Behandlungsverläufe mittels Intention-to-Treat Analysen bezüglich ihrer Cannabiskonsumtage und ihrer Werte auf dem Cannabis Use Disorder Identification Test (CUDIT), der Severity of Dependence Scale (SDS), der GAD-7, der Center of Epidemiologic Studies of Depression Scale (CES-D) sowie bezüglich ihrer Adhärenz verglichen.

Ergebnisse Alle 4 Gruppen reduzierten unabhängig von ihrer GAD-Symptomatik die Anzahl ihrer Cannabiskonsumtage, ihren CUDIT und SDS Score sowohl 6 Wochen als auch 3 Monate nach der Baselineerhebung. Weiter haben mit Ausnahme von der minimalen GAD-7-Gruppe alle Gruppen eine Reduktion der Angstsymptomatik nach 3 Monaten aufgewiesen. Analog zeigten mit Ausnahme der minimalen GAD-7-Gruppe alle GAD-7-Gruppen eine deutliche Reduktion in der depressiven Symptomatik. Bezüglich der gemessenen Adhärenz zeigten sich keine Unterschiede zwischen den GAD-7-Gruppen.

Schlussfolgerungen CANreduce 2.0 scheint sowohl den Cannabiskonsum, die Ausprägung der Cannabiskonsumstörung bzw. die Cannabisabhängigkeit wie auch eine gegebenenfalls vorhandene GAD-Symptomatik zu reduzieren.

Cannabis, a cause for anxiety? A critical appraisal of the anxiogenic and anxiolytic properties

BACKGROUND

Cannabis has been documented for use in alleviating anxiety. However, certain research has also shown that it can produce feelings of anxiety, panic, paranoia and psychosis. In humans, Δ9-tetrahydrocannabinol (THC) has been associated with an anxiogenic response, while anxiolytic activity has been attributed mainly to cannabidiol (CBD). In animal studies, the effects of THC are highly dose-dependent, and biphasic effects of cannabinoids on anxiety-related responses have been extensively documented. A more precise assessment is required of both the anxiolytic and anxiogenic potentials of phytocannabinoids, with an aim towards the development of the 'holy grail' in cannabis research, a medicinally-active formulation which may assist in the treatment of anxiety or mood disorders without eliciting any anxiogenic effects.

OBJECTIVES

To systematically review studies assessing cannabinoid interventions (e.g. THC or CBD or whole cannabis interventions) both in animals and humans, as well as recent epidemiological studies reporting on anxiolytic or anxiogenic effects from cannabis consumption.

METHOD

The articles selected for this review were identified up to January 2020 through searches in the electronic databases OVID MEDLINE, Cochrane Central Register of Controlled Trials, PubMed, and PsycINFO.

RESULTS

Acute doses of CBD were found to reduce anxiety both in animals and humans, without having an anxiogenic effect at higher doses. Epidemiological studies tend to support an anxiolytic effect from the consumption of either  CBD or THC, as well as whole plant cannabis. Conversely, the available human clinical studies demonstrate a common anxiogenic response to THC (especially at higher doses).

CONCLUSION

Based on current data, cannabinoid therapies (containing primarily CBD) may provide a more suitable treatment for people with pre-existing anxiety or as a potential adjunctive role in managing anxiety or stress-related disorders. However, further research is needed to explore other cannabinoids and phytochemical constituents present in cannabis (e.g. terpenes) as anxiolytic interventions. Future clinical trials involving patients with anxiety disorders are warranted due to the small number of available human studies.

Shifting the Paradigm on Cannabis Safety

The global movement toward legalization of cannabis is resulting in an ever-increasing public perception that cannabis is safe. Cannabis is not the first drug to be available for nonmedical use, nor is it the first to have such an unfounded safety profile. The safety of long-term exposure to phytocannabinoids is misunderstood by, and under reported to, the general public. There is evidence to suggest that long-term use of recreational cannabis may be associated with an increased risk of undesirable side effects. This evidence warrants both appropriate caution from the general public and investment in further research by government and industry sectors that are profiting from the sale of these potent psychoactive agents. There is no doubt that these compounds have medical potential. However, in addition to the medical potential, we must also remain aware of the adverse health effects that are becoming synonymous with recreational cannabis use. This perspective highlights the privileged role that cannabis has as a perceived “safe drug” in society and summarizes some concerning side effects that are becoming associated with regular nonprescribed cannabis use.

Is time elapsed between cannabis use and sleep start time associated with sleep continuity? An experience sampling method

BACKGROUND

A substantial proportion of people using cannabis report using it to improve sleep. Yet, little research exists on the associations between the timing of cannabis use and sleep. This study examines the time elapsed between cannabis use and sleep start time and its association with two of the main indicators of sleep continuity: (1) sleep onset latency (SOL) and (2) number of awakenings (NOA) throughout the night.

METHODS

Each morning, for 7 consecutive days, daily cannabis users (n = 54) reported on the timing of previous night's cannabis use and sleep indicators on their smartphones. Mixed effects models examined the relations of within- and between-subjects' time elapsed between previous night cannabis use and sleep start time, with (1) SOL and (2) NOA.

RESULTS

Within subjects, shorter time elapsed between cannabis use and sleep start time was associated with shorter SOL (β = 0.519, p = 0.010), but not NOA (β = -0.030, p = 0.535). Furthermore, between individuals, the time gap between the previous night cannabis use and sleep start time was not associated with SOL or NOA (p > 0.05).

CONCLUSIONS

It is possible that cannabis use proximal to bedtime is associated with shorted sleep onset latency but not nighttime awakenings. Cannabis users should be informed about both the potential sleep aid effects of cannabis and its limitations. Pending further evidence of the effects of cannabis on sleep, cannabis users experiencing sleep problems should be provided with evidence-based alternatives to improve sleep, e.g., pharmacological and behavioral treatments.

Higher odds of irritable bowel syndrome among hospitalized patients using cannabis: a propensity-matched analysis

BACKGROUND

The endogenous cannabinoid system modulates many brain-gut and gut-brain physiologic pathways, which are postulated to be dysfunctional in irritable bowel syndrome (IBS). Herein, we examine the relationship between cannabis use disorder (CUD) and having IBS.

PATIENTS AND METHODS

After selecting patients aged 18 years and above from the 2014 Nationwide Inpatient Survey, we used the International Classification of Diseases, 9th ed. codes to identify individuals with CUD, IBS, and the established risk factors for IBS. We then estimated the crude and adjusted odds ratios of having a diagnosis of IBS with CUD and assessed for the interactions of CUD with other risk factors (SAS 9.4). We confirmed our findings in two ways: conducting a similar analysis on a previous Nationwide Inpatient Survey data (2012); and using a greedy algorithm to design a propensity-scored case-control (1 : 10) study, approximating a pseudorandomized clinical trial.

RESULTS

Out of 4 709 043 patients evaluated, 0.03% had a primary admission for IBS and 1.32% had CUD. CUD was associated with increased odds of IBS [adjusted odds ratio: 2.03; 95% confidence interval (CI): 1.53-2.71]. CUD was related to higher odds for IBS among males compared with females (3.48; 1.98-6.12 vs. 1.48; 0.88-2.50), and Hispanics and Caucasians compared with Blacks (5.28; 1.77-15.76, 1.80; 1.02-3.18 vs. 1.80; 0.65-5.03). On propensity-matching, CUD was associated with 80% increased odds for IBS (1.82; 1.27-2.60).

CONCLUSION

Our findings suggest that CUD is significantly associated with IBS among the general population. Males, Caucasians, and Hispanics might be more impacted by CUD associated IBS. Additional biomedical studies are required to elucidate this relationship.

A longitudinal analysis of cannabis use and mental health symptoms among gay, bisexual, and other men who have sex with men in Vancouver, Canada

BACKGROUND

Cannabis use, anxiety, and depression are common among gay, bisexual, and other men who have sex with men (gbMSM) and some report using cannabis to manage mental health symptoms.

METHODS

Sexually-active gbMSM aged ≥16 years were recruited into a longitudinal cohort through respondent-driven sampling and completed study visits every six months. Data on demographics, drug use, and anxiety and depression symptoms were collected via a self-administered computer-based survey. A study nurse determined previous mental health diagnoses and treatment. Using multivariable generalized linear mixed models, we examined factors associated with regular cannabis use (≥weekly in the previous 3 months) and, among individuals who reported anxiety or depression/bipolar diagnoses, factors associated with moderate/severe anxiety or depression symptoms.

RESULTS

Of 774 participants (551 HIV-negative, 223 HIV-seropositive), 250 (32.3%) reported regular cannabis use, 200 (26.4%) reported ever being diagnosed with anxiety, and 299 (39.3%) reported ever being diagnosed with depression or bipolar disorder at baseline. Regular cannabis use was positively associated with HIV-seropositivity (aOR = 2.23, 95%CI:1.40-3.54) and previous mental health diagnosis (aOR = 1.52, 95%CI: 1.00-2.31, p = 0.05). Among those previously diagnosed with anxiety or depression/bipolar disorder, regular cannabis use was not associated with moderate/severe anxiety (aOR = 1.16, 95%CI:0.69-1.94) or depression symptoms (aOR = 0.96, 95%CI:0.59-1.58), respectively.

LIMITATIONS

Because of observational study design, we are unable to determine absolute effect.

CONCLUSIONS

Regular cannabis use was more likely among HIV-positive gbMSM and those previously diagnosed with a mental health disorder. No association was found between regular cannabis use and severity of anxious or depressive symptoms among those diagnosed with these conditions.

Cannabis and mental illness: a review

With the increasing push to legalize cannabis in Western nations, there is a need to gage the potential impact of this policy change on vulnerable populations, such as those with mental illness, including schizophrenia, mood, and anxiety disorders. This is particularly important as there are strong motives in these individuals to seek short-term reward (e.g., "getting high"). Nonetheless, data to support the beneficial effects of cannabis use in psychiatric populations are limited, and potential harms in patients with psychotic and mood disorders have been increasingly documented. This article reviews the effects of cannabis in people with mental illness. Then, we provide a reconciliation of the addiction vulnerability and allostatic hypotheses to explain co-morbidity addiction in mentally ill cannabis users, as well as to further aid in developing a rational framework for the assessment and treatment of problematic cannabis use in these patients.

The association between physical pain and cannabis use in daily life: An experience sampling method

BACKGROUND

Previous research shows that between individuals there is a positive association between medically motivated use and cannabis use frequency and quantity. While between-subjects' analyses are useful for understanding shared vulnerabilities, research has so far not examined within-subjects' relationships which are closer to evaluating functional relationships (i.e., do individuals tend to use cannabis more heavily subsequent to elevations in pain experiences?). To better understand the association between experiences of pain and cannabis use, the current paper examines whether there is a functional within-subjects association between experiences of pain and heavy cannabis use.

METHODS

182 regular cannabis users without a medical cannabis license were asked to report momentary experiences of physical pain, whether they had used cannabis, and if so, quantity consumed five times per day over a five-day period on their smartphones. Mixed effects models examined the relations between within- and between-subjects experiences of pain and cannabis use and quantity consumed.

RESULTS

Elevated experiences of pain were not associated with cannabis use occasions at the within- or between-subjects level. Experiences of pain were associated with greater amount of cannabis consumed at the within-subjects level, but not at the between-subjects level.

CONCLUSIONS

Experiences of pain are not associated with decisions about whether or not to use cannabis. Once cannabis users are in cannabis-using situations, they tend to use larger amounts when they are experiencing elevated levels of pain. This may have implications for cannabis abuse treatment as pain may make it more difficult for users to reduce their consumption.

Affect and cannabis use in daily life: a review and recommendations for future research

BACKGROUND

Although cannabis is often used for the purposes of relieving negative affective states such as anxiety and depression, the associations between cannabis use and affect in daily life are unclear. Ecological momentary assessment (EMA) has been used to study these associations in individuals' natural environments, providing more ecological validity, minimizing retrospective bias, and allowing for the analysis of within-individual processes over time. This review focuses on studies that utilized EMA to examine daily-life associations of cannabis use and negative and positive affective states.

METHODS

We review the findings of the 19 articles that met inclusion criteria, including clinical and community samples.

RESULTS

Results provide equivocal evidence regarding relations between cannabis use and affect for community samples. Findings are mixed for clinical samples as well, but more consistent patterns emerge for general negative affect (NA) and anger/hostility at the momentary level; cannabis use may be more likely following increased NA and lead to decreases in NA and anger/hostility in psychiatric populations.

CONCLUSIONS

Findings support a negative reinforcement hypothesis for clinical samples in terms of general NA and anger/hostility. However, discrepancies among studies point to a need to thoroughly characterize samples, consider motives for and expectancies of use, improve quantification of cannabis use, and consider co-use with other substances. Additional design recommendations are also offered for future studies.

Does social context matter? An ecological momentary assessment study of marijuana use among college students

INTRODUCTION

Past research has shown that marijuana use occurs commonly in social situations for young adults, though few studies have examined the association between immediate social context and marijuana use patterns and associated problems. The current study examined the impact of demographics, marijuana use and problem use, alcohol use, craving, and social context on the likelihood of using marijuana with others via ecological momentary assessment (EMA).

METHODS

College-student marijuana users (N=56) were recruited and completed a baseline assessment and training on the two-week signal-contingent EMA protocol. Participants were sent text messages three times per day randomly for two weeks.

RESULTS

Of the 1131 EMA instances during which participants reported using marijuana, 862 (76.22%) were labeled as being with others. Forty-five participants (80.36%) reported marijuana use with others present during at least half of the times they used marijuana. Findings from a multilevel logistic regression model showed a significant positive association between the probability of using with others and minutes spent using marijuana (b=0.047, p<0.001), social facilitation (b=0.138, p<0.001), and DSM-IV diagnosis (dependence versus no diagnosis, b=1.350, p=0.047).

CONCLUSIONS

Cannabis dependence, more time using marijuana in the moment, and using for social facilitation purposes were positively associated with using marijuana in the context of being with others. Daily users had more variability in terms of the social context of their use. This study illustrates the complex relationship between social context and marijuana use.

Mental Health-related Emergency Department Visits Associated With Cannabis in Colorado

BACKGROUND

Cannabis legalization in Colorado resulted in increased cannabis-associated health care utilization. Our objective was to examine cooccurrence of cannabis and mental health diagnostic coding in Colorado emergency department (ED) discharges and replicate the study in a subpopulation of ED visits where cannabis involvement and psychiatric diagnosis were confirmed through medical review.

METHODS

We collected statewide ED International Classification of Diseases, 9th Revision, Clinical Modification diagnoses from the Colorado Hospital Association and a subpopulation of ED visits from a large, academic hospital from 2012 to 2014. Diagnosis codes identified visits associated with mental health and cannabis. Codes for mental health conditions and cannabis were confirmed by manual records review in the academic hospital subpopulation. Prevalence ratios (PRs) of mental health ED discharges were calculated to compare cannabis-associated visits to those without cannabis. Rates of mental health and cannabis-associated ED discharges were examined over time.

RESULTS

Statewide data demonstrated a fivefold higher prevalence of mental health diagnoses in cannabis-associated ED visits (PR = 5.35, 95% confidence interval [CI], 5.27-5.43) compared to visits without cannabis. The hospital subpopulation supported this finding with a fourfold higher prevalence of psychiatric complaints in cannabis attributable ED visits (PR = 4.87, 95% CI = 4.36-5.44) compared to visits not attributable to cannabis. Statewide rates of ED visits associated with both cannabis and mental health significantly increased from 2012 to 2014 from 224.5 to 268.4 per 100,000 (p < 0.0001).

CONCLUSIONS

In Colorado, the prevalence of mental health conditions in ED visits with cannabis-associated diagnostic codes is higher than in those without cannabis. There is a need for further research determining if these findings are truly attributed to cannabis or merely coincident with concurrent increased use and availability.

The association between adolescent cannabis use and anxiety: A parallel process analysis

INTRODUCTION

Associations between anxiety symptoms and cannabis use have been previously explored, yet the directionality of these associations remains highly debatable. The present study aims to prospectively examine patterns of cannabis use and anxiety during adolescence focusing on their co-development and bidirectional influences.

METHODS

Adolescents (n=250) of predominantly Hispanic ethnicity, aged 14-17 at baseline, exposed to drugs, alcohol, or cigarettes completed three (bi-annual) assessments across a 1-year period. Latent growth curve modeling (LGCM) and parallel process growth curves were conducted to examine potential associations in the joint development of anxiety and cannabis use.

RESULTS

Our results suggest that, during adolescence, early cannabis use has a greater influence on prospective reports of anxiety, than vice versa. Specifically, adolescents exhibiting higher initial levels of cannabis use displayed more persisting self-reported anxiety across time, as compared to those with less frequent use (b=0.28, p=0.024). In contrast, early levels of anxiety were not found to influence rates of change in cannabis use. These analyses considered concurrent depression, alcohol, and nicotine use.

CONCLUSIONS

Our findings suggest that prevention and targeted intervention programs for cannabis use in adolescence would benefit from anxiety management strategies; in order to reduce subsequent anxiety associated with cannabis use. Future studies should continue to employ longitudinal designs across larger time periods and aim to replicate these findings with more diverse samples.

Factors Associated With Marijuana use and Problems Among College Students in Colorado

BACKGROUND

Past studies have shown that heavy marijuana use can impact student outcomes. Frequent use and misuse of marijuana have been associated with a range of psychological and personality factors in young adults, but there has been limited research focused on the college environment in states where marijuana has been legalized for recreational purposes.

OBJECTIVES

We examined whether marijuana use and problems were associated with a range of demographic, personality, and psychological variables among college students at a midsized Colorado university.

METHODS

This cross-sectional study included 300 university students who submitted a urine screen and completed measures on marijuana use, problem marijuana use, anxiety, depression, impulsivity, and openness to experience.

RESULTS

Last year and recent marijuana use were high (65%, 29%; respectively), as assessed through self-report and a urine screen. Using logistic regression, male sex and greater openness to experience were associated with greater marijuana use when assessed with a urine screen, while greater openness to experience and impulsivity were associated with greater self-reported marijuana use within the last year. In the final step of a hierarchical linear regression model, male sex and greater impulsivity and depression-but not openness to experience, general anxiety or social anxiety-were associated with greater problem marijuana use.

CONCLUSIONS

This study extends the literature on psychological and personality correlates of marijuana use among college students. It may be useful to assess these correlates to identify students who are at risk of developing problems and in intervening with students with problem use.

Co-localization of the cannabinoid type 1 receptor with corticotropin-releasing factor-containing afferents in the noradrenergic nucleus locus coeruleus: implications for the cognitive limb of the stress response

The noradrenergic system has been shown to play a key role in the regulation of stress responses, arousal, mood, and emotional states. Corticotropin-releasing factor (CRF) is a primary mediator of stress-induced activation of noradrenergic neurons in the nucleus locus coeruleus (LC). The endocannabinoid (eCB) system also plays a key role in modulating stress responses, acting as an "anti-stress" neuro-mediator. In the present study, we investigated the cellular sites for interactions between the cannabinoid receptor type 1 (CB1r) and CRF in the LC. Immunofluorescence and high-resolution immunoelectron microscopy showed co-localization of CB1r and CRF in both the core and peri-LC areas. Semi-quantitative analysis revealed that 44% (208/468) of CRF-containing axon terminals in the core and 35% (104/294) in the peri-LC expressed CB1r, while 18% (85/468) of CRF-containing axon terminals in the core and 6.5% (19/294) in the peri-LC were presynaptic to CB1r-containing dendrites. In the LC core, CB1r + CRF axon terminals were more frequently of the symmetric (inhibitory) type; while in the peri-LC, a majority were of the asymmetric (excitatory) type. Triple label immunofluorescence results supported the ultrastructural analysis indicating that CB1r + CRF axon terminals contained either gamma amino butyric acid or glutamate. Finally, anterograde transport from the central nucleus of the amygdala revealed that CRF-amygdalar afferents projecting to the LC contain CB1r. Taken together, these results indicate that the eCB system is poised to directly modulate stress-integrative heterogeneous CRF afferents in the LC, some of which arise from limbic sources.

Anxiety Sensitivity and Distress Intolerance as Predictors of Cannabis Dependence Symptoms, Problems, and Craving: The Mediating Role of Coping Motives

OBJECTIVE

The tendency to react with fear to anxiety-related sensations (anxiety sensitivity) and the inability to tolerate distressing psychological or physiological states (distress intolerance) are implicated in the comorbidity between affective psychopathology and cannabis use disorders. Emotionally vulnerable cannabis users may be particularly apt to use cannabis to cope with distress, which may both lead to and maintain its problematic use (e.g., dependence, craving). The current study tested a comprehensive model of anxiety sensitivity and distress intolerance as predictors of the number of cannabis dependence symptoms and problems, and severity of cannabis craving following deprivation from cannabis, and the mediating role of cannabis coping motives.

METHOD

Participants (n = 103; mean age = 21.2 years, SD = 4.3; 35.9% female) were non-treatment-seeking frequent cannabis users. Data were cross-sectional in nature. Anxiety sensitivity was assessed via self-report, and distress intolerance was assessed via both self-report and breath-holding duration.

RESULTS

Greater perceived distress intolerance, but not breath-holding duration or anxiety sensitivity, was associated with a greater number of cannabis dependence symptoms and problems and elevated cannabis craving. These relations were mediated by cannabis coping motives.

CONCLUSIONS

Findings provide specificity for the etiologic mechanisms related to emotional vulnerability and maintenance of cannabis problems. Perceived distress intolerance appears to be uniquely related to maladaptive coping motives for cannabis use, which could be meaningfully targeted in interventions for emotionally vulnerable cannabis users.

Assessing Energy Intake in Daily Life: Signal-Contingent Smartphone Application Versus Event-Contingent Paper and Pencil Estimated Diet Diary

Objectives:

Investigating between-meal snack intake and its associated determinants such as emotions and stress presents challenges because both vary from moment to moment throughout the day. A smartphone application (app), was developed to map momentary between-meal snack intake and its associated determinants in the context of daily life. The aim of this study was to compare energy intake reported with the signal-contingent app and reported with an event-contingent paper and pencil diet diary.

Methods:

In a counterbalanced, cross-sectional design, adults (N = 46) from the general population reported between-meal snack intake during four consecutive days with the app and four consecutive days with a paper and pencil diet diary. A 10-day interval was applied between the two reporting periods. Multilevel regression analyses were conducted to compare both instruments on reported momentary and daily energy intake from snacks.

Results:

Results showed no significant difference (B = 11.84, p = .14) in momentary energy intake from snacks between the two instruments. However, a significant difference (B = –105.89, p < .01) was found on energy intake from total daily snack consumption.

Conclusions:

As at momentary level both instruments were comparable in assessing energy intake, research purposes will largely determine the sampling procedure of choice. When momentary associations across time are the interest of study, a signal-contingent sampling procedure may be a suitable method. Since the compared instruments differed on two main features (i.e. the sampling procedure and the device used) it is difficult to disentangle which instrument was the most accurate in assessing daily energy intake.

Momentary positive and negative affect preceding marijuana use events in youth

ABSTRACT. among young people. This study examined how positive and negative affect differ before marijuana use compared with other times.

METHOD

Forty medical outpatients ages 15-24 years who used marijuana recreationally at least twice a week (M = 18.7 years; 58% female) reported momentary positive affect, negative affect, companionship, perceived ease of obtaining marijuana, and marijuana use several times a day for 2 weeks on a handheld computer. Mean momentary positive affect and negative affect scores in the 24 hours leading up to a marijuana use event (n = 294) were compared with affect scores in times further from subsequent use. Generalized estimating equation models considered as potential moderators perceived ease of obtaining marijuana and being with friends.

RESULTS

Positive affect did not differ in the 24 hours before marijuana use compared with times further before use. Negative affect was significantly higher before marijuana use compared with other times. Being with friends and perceived easy marijuana availability did not moderate the associations. The association between negative affect and subsequent marijuana use was attenuated when negative affect was examined only for the moment just before use, suggesting that use may follow a period of increased negative affect.

CONCLUSIONS

The findings support an affect regulation model for marijuana use among frequently using youth. Specifically, these youth may use marijuana to manage increased negative affect.

Psychiatric Symptoms, Salivary Cortisol and Cytokine Levels in Young Marijuana Users

Psychological maturation continues into young adulthood when substance abuse and several psychiatric disorders often emerge. Marijuana is the most common illicit drug abused by youths, typically preceding other illicit substances. We aimed to evaluate the complex and poorly studied relationships between marijuana use, psychiatric symptoms, and cortisol levels in young marijuana users. Psychiatric symptoms and salivary cortisol were measured in 122 youths (13-23 years old) with and without marijuana use. Psychiatric symptoms were evaluated using the Symptom-Checklist-90-R and Brief Psychiatric Rating Scale. Mid-day salivary cortisol levels were measured. Additionally, salivary cytokine levels were measured in a subset of participants. Although the cortisol levels and salivary cytokine levels were similar, the young marijuana users had more self-reported and clinician rated psychiatric symptoms than controls, especially anxiety-associated symptoms. Moreover, marijuana users with earlier age of first use had more symptoms, while those with longer abstinence had fewer symptoms. Greater cumulative lifetime marijuana use was also associated with greater psychiatric symptoms. The discordant anxiety (feeling stressed or anxious despite normal cortisol) in the marijuana users, as well as symptom exacerbations with early and continued marijuana use in young marijuana users suggest that marijuana use may contribute to an aberrant relationship between stress response and psychiatric symptoms. The greater symptomatology, especially in those with earlier initiation and greater marijuana usage, emphasize the need to intervene for substance use and perceived anxiety in this population.

Cannabis use and anxiety: is stress the missing piece of the puzzle?

OBJECTIVE

Comorbidity between anxiety and cannabis use is common yet the nature of the association between these conditions is not clear. Four theories were assessed, and a fifth hypothesis tested to determine if the misattribution of stress symptomology plays a role in the association between state-anxiety and cannabis.

METHODS

Three-hundred-sixteen participants ranging in age from 18 to 71 years completed a short online questionnaire asking about their history of cannabis use and symptoms of stress and anxiety.

RESULTS

Past and current cannabis users reported higher incidence of lifetime anxiety than participants who had never used cannabis; however, these groups did not differ in state-anxiety, stress, or age of onset of anxiety. State-anxiety and stress were not associated with frequency of cannabis use, but reported use to self-medicate for anxiety was positively associated with all three. Path analyses indicated two different associations between anxiety and cannabis use, pre-existing and high state-anxiety was associated with (i) higher average levels of intoxication and, in turn, acute anxiety responses to cannabis use; (ii) frequency of cannabis use via the mediating effects of stress and self-medication.

CONCLUSION

None of the theories was fully supported by the findings. However, as cannabis users reporting self-medication for anxiety were found to be self-medicating stress symptomology, there was some support for the stress-misattribution hypothesis. With reported self-medication for anxiety being the strongest predictor of frequency of use, it is suggested that researchers, clinicians, and cannabis users pay greater attention to the overlap between stress and anxiety symptomology and the possible misinterpretation of these related but distinct conditions.

Long-term consequences of adolescent cannabinoid exposure in adult psychopathology

Marijuana is the most widely used illicit drug among adolescents and young adults. Unique cognitive, emotional, and social changes occur during this critical period of development from childhood into adulthood. The adolescent brain is in a state of transition and differs from the adult brain with respect to both anatomy (e.g., neuronal connections and morphology) and neurochemistry (e.g., dopamine, GABA, and glutamate). These changes are thought to support the emergence of adult cerebral processes and behaviors. The endocannabinoid system plays an important role in development by acting on synaptic plasticity, neuronal cell proliferation, migration, and differentiation. Delta-9-tetrahydrocanabinol (THC), the principal psychoactive component in marijuana, acts as a partial agonist of the cannabinoid type 1 receptor (CB1R). Thus, over-activation of the endocannabinoid system by chronic exposure to CB1R agonists (e.g., THC, CP-55,940, and WIN55,212-2) during adolescence can dramatically alter brain maturation and cause long-lasting neurobiological changes that ultimately affect the function and behavior of the adult brain. Indeed, emerging evidence from both human and animal studies demonstrates that early-onset marijuana use has long-lasting consequences on cognition; moreover, in humans, this use is associated with a two-fold increase in the risk of developing a psychotic disorder. Here, we review the relationship between cannabinoid exposure during adolescence and the increased risk of neuropsychiatric disorders, focusing on both clinical and animal studies.

Chronic THC during adolescence increases the vulnerability to stress-induced relapse to heroin seeking in adult rats

Cannabis derivatives are among the most widely used illicit substances among young people. The addictive potential of delta-9-tetrahydrocannabinol (THC), the major active ingredient of cannabis is well documented in scientific literature. However, the consequence of THC exposure during adolescence on occurrence of addiction for other drugs of abuse later in life is still controversial. To explore this aspect of THC pharmacology, in the present study, we treated adolescent rats from postnatal day (PND) 35 to PND-46 with increasing daily doses of THC (2.5-10mg/kg). One week after intoxication, the rats were tested for anxiety-like behavior in the elevated plus maze (EPM) test. One month later (starting from PND 75), rats were trained to operantly self-administer heroin intravenously. Finally, following extinction phase, reinstatement of lever pressing elicited by the pharmacological stressor, yohimbine (1.25mg/kg) was evaluated. Data revealed that in comparison to controls, animals treated with chronic THC during adolescence showed a higher level of anxiety-like behavior. When tested for heroin (20μg per infusion) self-administration, no significant differences were observed in both the acquisition of operant responding and heroin intake at baseline. Noteworthy, following the extinction phase, administration of yohimbine elicited a significantly higher level of heroin seeking in rats previously exposed to THC. Altogether these findings demonstrate that chronic exposure to THC during adolescence is responsible for heightened anxiety and increased vulnerability to drug relapse in adulthood.

Individual and contextual predictors of severity of marijuana use events among young frequent users

This study used momentary sampling to characterize marijuana events among young frequent users and determine contextual and individual predictors of use severity. Medical clinic outpatients aged 15-24 who used marijuana at least twice a week completed a baseline assessment, then used a handheld computer to report marijuana use at 4-6 signal-prompted times per day and before/after use for 2 weeks. Reports assessed event characteristics (when, with whom, where, how, why, how much, how high). Timestamps identified time, weekend, and duration for each event. Generalized estimating equations tested associations of individual and event-specific contextual characteristics with hits/event, duration, and high. Forty-one youth completed 3868 momentary reports; 40 (98%) reported at least one marijuana use event (N=432 events; M=10.5/participant) and thus provided data for these analyses. Marijuana was most commonly used with other people (74% of events), at home (58%), via blunt (66%), and for social or enhancement reasons (86%). Most events (62%) occurred on weekdays; use was least likely in the morning (8%). Most events involved 6 or more hits (81%). Mean high was 5.2 (out of 8). Of events with start and end times (n=250), mean duration was 46.8 min. Poor mental health and use with a blunt or a bong, in the morning or evening, and on the weekend were associated with 6 or more hits/event. Female gender was associated with greater event duration. Poor mental health predicted higher high. Among youth who used it frequently, marijuana was used in a variety of contexts, with diversity in method, dose, and duration. Contextual factors appeared to predict marijuana dose for a given event, while individual characteristics were more predictive of high and duration.

Immediate antecedents of marijuana use: an analysis from ecological momentary assessment

BACKGROUND AND OBJECTIVES

Marijuana remains the most commonly used illicit substance. Marijuana craving, anxiety, and peer marijuana use are thought to play important roles in the etiology and maintenance of marijuana use. The present study aimed to identify patterns between marijuana use and these affective and situational risk factors in the natural environment.

METHODS

The sample consisted of 49 current marijuana users (38.8% female), 63.2% of whom evinced a current cannabis use disorder. Ecological momentary assessment was used to collect multiple daily ratings of marijuana craving, state anxiety, and peer marijuana use over two weeks. Mixed effects linear models were used to examine within- and between-day antecedents, correlates, and consequences of marijuana use.

RESULTS

Between-day analyses indicated that marijuana use days were associated with higher marijuana craving but lower state anxiety. Within-day analyses confirmed that marijuana craving was higher prior to marijuana use and lower following use. Anxiety was related to marijuana craving. Although anxiety was somewhat higher prior to marijuana use, it did not decrease significantly following use. The vast majority of marijuana use occurred when others were also using marijuana.

LIMITATIONS

The sample was comprised of college students, a group at particular risk for marijuana use and use-related problems. Future work is necessary to determine whether results generalize to other populations.

CONCLUSIONS

These data support the contention that marijuana craving, anxiety, and peer use play important roles in the maintenance of marijuana use.

A neuroimmunological perspective on anxiety disorders

OBJECTIVE

Research into psychoneuroimmunology has led to substantial advances in our understanding of the reciprocal interactions between the central nervous system and the immune system in neuropsychiatric disorders. To date, the presence of inflammatory responses and the crucial role of cytokines in major depression have been addressed in numerous studies. However, neuroinflammatory hypotheses in anxiety disorders have been studied less extensively than in major depression. There is a high research need for better understanding of both the heterogeneous role of specific cytokines in the control of anxious states and in different anxiety disorders and of the immunomodulating effects of antidepressants on anxiety.

METHODS

Relevant literature was identified through a search of MEDLINE via PubMed. We discuss recent research on neuroimmunology in anxiety and make methodological recommendations for future investigation of neuroinflammatory hypotheses in anxiety disorders.

RESULTS

Some accumulating evidence has indicated modulatory effects of cytokines on neuronal communication and anxiety; however, research has not revealed consistent reproducible findings.

CONCLUSIONS

The availability of inflammatory biomarkers may provide an opportunity to identify patients via specific pathophysiological processes and to monitor therapeutic responses within relevant pathways. Further understanding of the neuroimmunological mechanisms to untangle the reciprocal associations between inflammation and anxiety is warranted.

Endocannabinoid influence in drug reinforcement, dependence and addiction-related behaviors

The endogenous cannabinoid system is an important regulatory system involved in physiological homeostasis. Endocannabinoid signaling is known to modulate neural development, immune function, metabolism, synaptic plasticity and emotional state. Accumulating evidence also implicates brain endocannabinoid signaling in the etiology of drug addiction which is characterized by compulsive drug seeking, loss of control in limiting drug intake, emergence of a negative emotional state in the absence of drug use and a persistent vulnerability toward relapse to drug use during protracted abstinence. In this review we discuss the effects of drug intake on brain endocannabinoid signaling, evidence implicating the endocannabinoid system in the motivation for drug consumption, and drug-induced alterations in endocannabinoid function that may contribute to various aspects of addiction including dysregulated synaptic plasticity, increased stress responsivity, negative affective states, drug craving and relapse to drug taking. Current knowledge of genetic variants in endocannabinoid signaling associated with addiction is also discussed.

Endocannabinoid-mediated synaptic plasticity and addiction-related behavior

Endogenous cannabinoids (eCBs) are retrograde messengers that provide feedback inhibition of both excitatory and inhibitory transmission in brain through the activation of presynaptic CB₁ receptors. Substantial evidence indicates that eCBs mediate various forms of short- and long-term plasticity in brain regions involved in the etiology of addiction. The present review provides an overview of the mechanisms through which eCBs mediate various forms of synaptic plasticity and discusses evidence that eCB-mediated plasticity is disrupted following exposure to a variety of abused substances that differ substantially in pharmacodynamic mechanism including alcohol, psychostimulants and cannabinoids. The possible involvement of dysregulated eCB signaling in maladaptive behaviors that evolve over long-term drug exposure is also discussed, with a particular focus on altered behavioral responses to drug exposure, deficient extinction of drug-related memories, increased drug craving and relapse, heightened stress sensitivity and persistent affective disruption (anxiety and depression).

Anxiety sensitivity and marijuana use: an analysis from ecological momentary assessment

BACKGROUND

The cognitive factor of Anxiety Sensitivity (AS; the fear of anxiety and related bodily sensations) is theorized to play a role in cannabis use and its disorders. Lower-order facets of AS (physical concerns, mental incapacitation concerns, and social concerns) may be differentially related to cannabis use behavior. However, little is known about the impact of AS facets on the immediate antecedents of cannabis use.

METHODS

This study used ecological momentary assessment (EMA) to prospectively examine the relations between specific facets of AS, cannabis craving, state anxiety, and cannabis use in the natural environment using real-world data about ad lib cannabis use episodes. Participants were 49 current cannabis users (38.8% female).

RESULTS

AS-mental incapacitation fears were related to significantly greater severity of cannabis-related problems at baseline. During the EMA period, AS-mental incapacitation and AS-social concerns significantly interacted with cannabis craving to prospectively predict subsequent cannabis use. Specifically, individuals with higher craving and either higher AS-mental incapacitation or AS-social concerns were the most likely to subsequently use cannabis. In contrast to prediction, no AS facet significantly moderated the relationship between state anxiety and cannabis use.

CONCLUSIONS

These findings suggest facets of AS (mental incapacitation and social fears) interact with cannabis craving to predict cannabis use. Findings also suggest differential relations between facets of AS and cannabis-related behaviors.

Modulation of the serotonin system by endocannabinoid signaling

The cannabinoid CB(1) receptors and their endogenous agonists, endocannabinoids (eCBs), are ubiquitously distributed throughout the central nervous system (CNS), where they play a key role in the regulation of neuronal excitability. As such, CB signaling has been implicated in the regulation of a myriad of physiological functions ranging from feeding homoeostasis to emotional and motivational processes. Ample evidence from behavioral studies also suggests that eCBs are important regulators of stress responses and a deficit in eCB signaling contributes to stress-related disorders such as anxiety and depression. The eCB-induced modulation of stress-related behaviors appears to be mediated, at least in part, through the regulation of the serotoninergic system. In this article, we review the role of eCB signaling in the regulation of the serotoninergic system with special emphasis on the cellular mechanisms by which cannabinoid CB(1) receptors modulate the excitability of dorsal raphe serotonin neurons.

Developmental consequences of perinatal cannabis exposure: behavioral and neuroendocrine effects in adult rodents

RATIONALE

Cannabis is the most commonly used illicit drug among pregnant women. Since the endocannabinoid system plays a crucial role in brain development, maternal exposure to cannabis derivatives might result in long-lasting neurobehavioral abnormalities in the exposed offspring. It is difficult to detect these effects, and their underlying neurobiological mechanisms, in clinical cohorts, because of their intrinsic methodological and interpretative issues.

OBJECTIVES

The present paper reviews relevant rodent studies examining the long-term behavioral consequences of exposure to cannabinoid compounds during pregnancy and/or lactation.

RESULTS

Maternal exposure to even low doses of cannabinoid compounds results in atypical locomotor activity, cognitive impairments, altered emotional behavior, and enhanced sensitivity to drugs of abuse in the adult rodent offspring. Some of the observed behavioral abnormalities might be related to alterations in stress hormone levels induced by maternal cannabis exposure.

CONCLUSIONS

There is increasing evidence from animal studies showing that cannabinoid drugs are neuroteratogens which induce enduring neurobehavioral abnormalities in the exposed offspring. Several preclinical findings reviewed in this paper are in line with clinical studies reporting hyperactivity, cognitive impairments and altered emotionality in humans exposed in utero to cannabis. Conversely, genetic, environmental and social factors could also influence the neurobiological effects of early cannabis exposure in humans.

Vulnerability Factors for the Psychiatric and Behavioral Effects of Cannabis

Cogent evidence shows that cannabis plays a variable role on behavioral regulation and the pathophysiology of most psychiatric conditions. Accordingly, cannabis has been alternatively shown to exacerbate or ameliorate mental symptoms, depending on its composition and route of consumption, as well as specific individual and contextual characteristics. The vulnerability to the psychological effects of cannabis is influenced by a complex constellation of genetic and environmental factors. In the present article, we will review the current evidence on the pharmacological, individual and situational factors that have been documented to affect the behavioral and psychiatric effects of cannabinoids.

Relationships over time between mental health symptoms and transmission risk among persons living with HIV

Relationships between mental health symptoms (anxiety and depression) or a positive state of mind and behavior associated with HIV transmission (substance use and risky sexual behavior) were explored in a longitudinal study of persons living with HIV (PLH; N = 936) who were participants in a transmission-prevention trial. Bivariate longitudinal regressions were used to estimate the correlations between mental health symptoms and HIV-related transmission acts for 3 time frames: at the baseline interview, over 25 months, and from assessment to assessment. At baseline, mental health symptoms were associated with transmission acts. Elevated levels of mental health symptoms at baseline were associated with decreasing alcohol or marijuana use over 25 months. Over 25 months, an increasingly positive state of mind was associated with decreasing alcohol or marijuana use; an increasingly positive state of mind in the immediate intervention condition and increasing depressive symptoms in the lagged condition were related to increasing risky sexual behavior. Our findings suggest that mental health symptoms precede a decrease in substance use and challenge self-medication theories. Changes in mental health symptoms and sexual behavior occur more in tandem.

Cannabis and anxiety: a critical review of the evidence

BACKGROUND

Anxiety reactions and panic attacks are the acute symptoms most frequently associated with cannabis use. Understanding the relationship between cannabis and anxiety may clarify the mechanism of action of cannabis and the pathophysiology of anxiety. Aims of the present study were to review the nature of the relationship between cannabis use and anxiety, as well as the possible clinical, diagnostic and causal implications.

METHOD

Systematic review of the Medline, PsycLIT and EMBASE literature.

RESULTS

Frequent cannabis users consistently have a high prevalence of anxiety disorders and patients with anxiety disorders have relatively high rates of cannabis use. However, it is unclear if cannabis use increases the risk of developing long-lasting anxiety disorders. Many hypotheses have been proposed in an attempt to explain these relationships, including neurobiological, environmental and social influences.

CONCLUSIONS

The precise relationship between cannabis use and anxiety has yet to be established. Research is needed to fully clarify the mechanisms of such the association.

Experience sampling research in psychopathology: opening the black box of daily life

A growing body of research suggests that momentary assessment technologies that sample experiences in the context of daily life constitute a useful and productive approach in the study of behavioural phenotypes and a powerful addition to mainstream cross-sectional research paradigms. Momentary assessment strategies for psychopathology are described, together with a comprehensive review of research findings illustrating the added value of daily life research for the study of (1) phenomenology, (2) aetiology, (3) psychological models, (4) biological mechanisms, (5) treatment and (6) gene-environment interactions in psychopathology. Overall, this review shows that variability over time and dynamic patterns of reactivity to the environment are essential features of psychopathological experiences that need to be captured for a better understanding of their phenomenology and underlying mechanisms. The Experience Sampling Method (ESM) allows us to capture the film rather than a snapshot of daily life reality of patients, fuelling new research into the gene-environment-experience interplay underlying psychopathology and its treatment.