Opioid antagonism of cannabinoid effects: differences between marijuana smokers and nonmarijuana smokers

Sex Differences in the Safety and Subjective Effects of Two Oral Δ9-Tetrahydrocannabinol-Containing Cannabis Products over Multiple Doses Among Healthy Adults

Introduction: A growing number of females report consuming cannabis products. There is a paucity of data on sex differences in safety and subjective effects after repeated use of varying oral doses of Δ9-tetrahydrocannabinol (THC; the primary psychoactive constituent of cannabis). Materials and Methods: Data were from two randomized, double-blind, placebo-controlled, multiple-dose, between-subject trials of two THC-containing oral cannabis products. Healthy adults received placebo, low-dose THC (∼2.5 or ∼5 mg per dose), or high-dose THC (∼7.5 or ∼10 mg per dose) twice daily for 7 days. There were 38 males (8 placebo, 17 low-dose THC, 13 high-dose THC) and 46 females (8 placebo, 17 low-dose THC, 21 high-dose THC). Analyses compared adverse events (AEs) and subjective effects between males and females, by THC dose. Results: In the placebo and low-dose THC groups, there were no sex differences in the relative rate of AEs. In the high-dose THC group, females versus males reported 3.08 (95% confidence interval [CI]=1.31-8.33) times as many AEs. There were no significant interactions of sex×low-dose THC group for any subjective effect. In the high-dose THC group, females versus males reported greater "relaxed" ratings (b=15.14, 95% CI=1.44-28.84, p=0.027), whereas in the placebo group, males versus females reported greater ratings of "liking the effect" (b=-30.01, 95% CI=2.77-57.26, p=0.028). Although analyses were underpowered to assess the sex×THC dose×day interaction, the initial sex disparity in AEs and some subjective effects in the high-dose THC group appeared to shrink after the first day. Conclusions: In this exploratory analysis, sex differences in some responses to oral THC were nuanced. Females appeared more sensitive than males to AEs and some subjective effects at higher but not lower doses. Males reported higher ratings than females on some subjective effects in response to placebo. Initial sex differences in response to higher doses of oral THC tended to diminish over 7 days of dosing. If replicated, findings could help inform sex-specific dosing strategies of medical cannabis products and could help educate medical cannabis patients on any temporality of effects.

Sex differences in the acute effects of oral THC: a randomized, placebo-controlled, crossover human laboratory study

RATIONALE

Recent reports have shown increased cannabis use among women, leading to growing concerns about cannabis use disorder (CUD). While there is preclinical evidence suggesting biological sex influences cannabinoid effects, human research remains scant. We investigated sex differences in the acute response to oral tetrahydrocannabinol (THC) in humans.

METHODS

56 healthy men and women with prior exposure to cannabis but no history of CUD participated in a randomized, placebo-controlled, human laboratory study where they received a single 10 mg dose of oral THC (dronabinol). Subjective psychoactive effects were assessed by the visual analog scale of "high", psychotomimetic effects by the Clinician-Administered Dissociative Symptoms Scale and Psychotomimetic States Inventory, verbal learning and memory by Rey Auditory Verbal Learning Test (RAVLT), and physiological effects by heart rate. Outcomes were regularly measured on the test day, except for the RAVLT, which was assessed once. Peak differences from baseline were analyzed using a nonparametric method for repeated measures.

RESULTS

Oral THC (10 mg) demonstrated significant dose-related effects in psychotomimetic and physiological domains, but not in RAVLT outcomes. A notable interaction between THC dose and sex emerged concerning the subjective "high" scores, with women reporting heightened sensations (p = 0.05). No other significant effects of sex and THC dose interaction were observed.

CONCLUSION

Oral THC (10 mg) yields similar acute psychotomimetic and physiological effects across sexes, but women may experience a pronounced subjective psychoactive effect. Further research is needed to identify individual vulnerabilities and facilitate tailored interventions addressing CUD.

CLINICALTRIALS

GOV REGISTRATION: https://clinicaltrials.gov/study/NCT02781519?term=Ranganathan&intr=THC&rank=3 .

Correlations of the CNR1 Gene with Personality Traits in Women with Alcohol Use Disorder

Alcohol use disorder (AUD) is a significant issue affecting women, with severe consequences for society, the economy, and most importantly, health. Both personality and alcohol use disorders are phenotypically very complex, and elucidating their shared heritability is a challenge for medical genetics. Therefore, our study investigated the correlations between the microsatellite polymorphism (AAT)n of the Cannabinoid Receptor 1 (CNR1) gene and personality traits in women with AUD. The study group included 187 female subjects. Of these, 93 were diagnosed with alcohol use disorder, and 94 were controls. Repeat length polymorphism of microsatellite regions (AAT)n in the CNR1 gene was identified with PCR. All participants were assessed with the Mini-International Neuropsychiatric Interview and completed the NEO Five-Factor and State-Trait Anxiety Inventories. In the group of AUD subjects, significantly fewer (AAT)n repeats were present when compared with controls (p = 0.0380). While comparing the alcohol use disorder subjects (AUD) and the controls, we observed significantly higher scores on the STAI trait (p < 0.00001) and state scales (p = 0.0001) and on the NEO Five-Factor Inventory Neuroticism (p < 0.00001) and Openness (p = 0.0237; insignificant after Bonferroni correction) scales. Significantly lower results were obtained on the NEO-FFI Extraversion (p = 0.00003), Agreeability (p < 0.00001) and Conscientiousness (p < 0.00001) scales by the AUD subjects when compared to controls. There was no statistically significant Pearson's linear correlation between the number of (AAT)n repeats in the CNR1 gene and the STAI and NEO Five-Factor Inventory scores in the group of AUD subjects. In contrast, Pearson's linear correlation analysis in controls showed a positive correlation between the number of the (AAT)n repeats and the STAI state scale (r = 0.184; p = 0.011; insignificant after Bonferroni correction) and a negative correlation with the NEO-FFI Openness scale (r = -0.241; p = 0.001). Interestingly, our study provided data on two separate complex issues, i.e., (1) the association of (AAT)n CNR1 repeats with the AUD in females; (2) the correlation of (AAT)n CNR1 repeats with anxiety as a state and Openness in non-alcohol dependent subjects. In conclusion, our study provided a plethora of valuable data for improving our understanding of alcohol use disorder and anxiety.

Sex Differences in the Acute Effects of Oral THC: A Randomized, Placebo-Controlled, Crossover Human Laboratory Study

Rationale

Recent reports have shown increased cannabis use among women, leading to growing concerns about cannabis use disorder (CUD). Some evidence suggests a faster progression to addiction in women, known as the "telescoping effect." While there is preclinical evidence suggesting biological sex influences cannabinoid effects, human research remains scant. We investigated sex differences in the response to oral tetrahydrocannabinol (THC) in humans.

Methods

56 healthy men and women with prior exposure to cannabis but no history of CUD participated in a randomized, placebo-controlled, human laboratory study where they received a single 10 mg dose of oral THC (dronabinol). Subjective psychoactive effects were assessed by the visual analog scale of "high", psychotomimetic effects by the Clinician-Administered Dissociative Symptoms Scale and Psychotomimetic States Inventory, verbal learning and memory by Rey Auditory Verbal Learning Test (RAVLT), and physiological effects by heart rate. Outcomes were regularly measured on the test day, except for the RAVLT, which was assessed once. Peak differences from baseline were analyzed using a nonparametric method for repeated measures.

Results

Oral THC demonstrated significant dose-related effects in psychotomimetic and physiological domains, but not in RAVLT outcomes. A notable interaction between THC dose and sex emerged concerning the subjective "high" scores, with women reporting heightened sensations (p=0.05). No other significant effects of sex and THC dose interaction were observed.

Conclusion

Oral THC yields similar psychotomimetic and physiological effects across sexes, but women may experience a pronounced subjective psychoactive effect. Further research is needed to identify individual vulnerabilities and facilitate tailored interventions addressing CUD.

Sex differences in acute delta-9-tetrahydrocannabinol (Δ9-THC) response and tolerance as a function of mouse strain

Cannabinoids are increasingly used to alleviate pain; however, tolerance to their antinociceptive effects, including those of delta-9-tetrahydrocannabinol (Δ9-THC), may limit their therapeutic utility. With more women than men using medical cannabis for pain relief, it is crucial to understand how sex influences cannabinoid-mediated antinociception and tolerance. Though studies in rats consistently find females are more sensitive to the acute antinociceptive effects of cannabinoids, our work with mice consistently finds the converse. The present study examined whether our observed sex differences in Δ9-THC-induced antinociception and tolerance are consistent across multiple mouse strains or are strain-dependent. Male and female C57BL/6J (B6), DBA/2, AKR, and CBA/J mice were assessed for differences in acute Δ9-THC-induced antinociception and hypothermia prior to and following seven days of once-daily Δ9-THC administration. Consistent with our previous findings, male B6 mice were more sensitive to the acute antinociceptive effects of Δ9-THC than female littermates, an effect which dissipated with age. B6 males had decreased cannabinoid expression in the PAG compared to females. While DBA and CBA female mice showed increased Δ9-THC-antinociception compared to male littermates at 30 and 10 mg/kg Δ9-THC, respectively, these differences were less pronounced at higher doses, revealing that dose of Δ9-THC may also be important. Overall, CBA mice were more sensitive to Δ9-THC-induced antinociception while AKR mice were less responsive. These studies highlight the therapeutic potential of Δ9-THC in pain management and underscore the importance of considering not only Δ9-THC dose as a function of sex, but potentially genetic differences when evaluating their clinical utility.

Mechanisms of cannabinoid tolerance

Cannabis has been used recreationally and medically for centuries, yet research into understanding the mechanisms of its therapeutic effects has only recently garnered more attention. There is evidence to support the use of cannabinoids for the treatment of chronic pain, muscle spasticity, nausea and vomiting due to chemotherapy, improving weight gain in HIV-related cachexia, emesis, sleep disorders, managing symptoms in Tourette syndrome, and patient-reported muscle spasticity from multiple sclerosis. However, tolerance and the risk for cannabis use disorder are two significant disadvantages for cannabinoid-based therapies in humans. Recent work has revealed prominent sex differences in the acute response and tolerance to cannabinoids in both humans and animal models. This review will discuss evidence demonstrating cannabinoid tolerance in rodents, non-human primates, and humans and our current understanding of the neuroadaptations occurring at the cannabinoid type 1 receptor (CB1R) that are responsible tolerance. CB1R expression is downregulated in tolerant animals and humans while there is strong evidence of CB1R desensitization in cannabinoid tolerant rodent models. Throughout the review, critical knowledge gaps are indicated and discussed, such as the lack of a neuroimaging probe to assess CB1R desensitization in humans. The review discusses the intracellular signaling pathways that are responsible for mediating CB1R desensitization and downregulation including the action of G protein-coupled receptor kinases, β-arrestin2 recruitment, c-Jun N-terminal kinases, protein kinase A, and the intracellular trafficking of CB1R. Finally, the review discusses approaches to reduce cannabinoid tolerance in humans based on our current understanding of the neuroadaptations and mechanisms responsible for this process.

Effects of Δ⁹-tetrahydrocannabinol (THC), cannabidiol (CBD), and THC/CBD mixtures on fentanyl versus food choice in rhesus monkeys

INTRODUCTION

There is considerable interest in utilizing cannabis-based products as adjuvants to opioid agonist therapies as phytocannabinoids like Δ9-tetrahydrocannabinol (THC) or synthetic cannabinoid receptor agonists appear to enhance the pain-relieving effects of opioids without enhancing problematic effects of opioids. Cannabis is a pharmacologically complex plant with hundreds of compounds, some of which may have interactive effects. Therefore, studying compounds like THC in isolation does not accurately reflect the clinical use of cannabis.

METHODS

This study examined the effects of THC and cannabidiol (CBD), the two most prominent compounds in cannabis, on the reinforcing effects of fentanyl in rhesus monkeys in a food versus drug choice procedure. Responding on one lever was reinforced by delivery of a sucrose pellet, and responding on another lever was reinforced by delivery of an i.v. infusion of fentanyl. In each monkey, the largest dose of fentanyl that produced less than 20 % drug choice and the smallest dose of fentanyl that produced more than 80% drug choice was determined. Effects of pretreatment with THC and CBD, alone and in mixtures, were then examined.

RESULTS

THC, CBD, and THC:CBD mixtures did not reliably enhance or diminish choice for fentanyl up to doses that suppressed responding in most monkeys, though some individual differences were observed, with THC and THC:CBD mixtures decreasing choice for large doses of fentanyl in one monkey and increasing choice for small doses of fentanyl in another.

CONCLUSIONS

Phytocannabinoids like THC and CBD, administered alone or in mixtures, do not appear to reliably alter the reinforcing effects of opioids.

Sex Differences in the Association Between Cannabis Use and Diabetes Mellitus among U.S. Adults: The National Health and Nutritional Examination Survey, 2013-2018

Background: Diabetes mellitus is an important public health problem in the United States, accounting for 87,647 deaths in 2019. This study aimed to assess the association between cannabis use and diabetes mellitus by sex among U.S. adults. Methods: Data were abstracted from the National Health and Nutrition Examination Survey (NHANES) from 2013 through 2018. Cannabis use was estimated using exposure status and frequency of use. Diabetes mellitus was assessed based on physician diagnosis or laboratory results, per the American Diabetes Association guidelines. A multivariable survey logistic regression model was fitted to estimate adjusted odds ratios (aOR) and confidence intervals (95% CIs). Results: A total of 15,062 participants were included in this study. The majority were female (n=7845; 51.1%), >40 years of age (n=8564; 56.3%), non-Hispanic white (n=4873; 61.5%), with at least a college-level education (n=8239; 62.5%). Female participants who used cannabis heavily were less likely to be diagnosed with diabetes mellitus than female noncannabis users (aOR=0.49; 95% CI: 0.30-0.81; aOR=0.51; 95% CI: 0.31-0.84). However, no significant association was found for female adults who engaged in light use of cannabis (aOR=0.98; 95% CI: 0.55-1.75; aOR=1.01; 95% CI: 0.57-1.79). Among male adults, cannabis use, irrespective of the degree of exposure, was not significantly associated with diabetes mellitus (heavy users: aOR=0.89; 95% CI=0.56-1.41; light users: aOR=0.53; 95% CI=0.22-1.29). Conclusions: Heavy cannabis use is inversely associated with diabetes mellitus in females but not males. Further studies are needed to explore the sex-based heterogeneity-and individual and contextual factors responsible-in the association between cannabis use and diabetes mellitus.

Sex-specific mechanisms of tolerance for the cannabinoid agonists CP55,940 and delta-9-tetrahydrocannabinol (Δ9-THC)

RATIONALE

Tolerance to cannabinoids could limit their therapeutic potential. Male mice expressing a desensitization-resistant form (S426A/S430A) of the type-1 cannabinoid receptor (CB₁R) show delayed tolerance to delta-9-tetrahydrocannabinol (∆⁹-THC) but not CP55,940. With more women than men using medical cannabis for pain relief, it is essential to understand sex differences in cannabinoid antinociception, hypothermia, and resultant tolerance.

OBJECTIVE

Our objective was to determine whether female mice rely on the same molecular mechanisms for tolerance to the antinociceptive and/or hypothermic effects of cannabinoids that we have previously reported in males. We determined whether the S426A/S430A mutation differentially disrupts antinociceptive and/or hypothermic tolerance to CP55,940 and/or Δ⁹-THC in male and female S426A/S430A mutant and wild-type littermates.

RESULTS

The S426A/S430A mutation conferred an enhanced antinociceptive response for ∆⁹-THC and CP55,940 in both male and female mice. While the S426A/S430A mutation conferred partial resistance to ∆⁹-THC tolerance in male mice, disruption of CB₁R desensitization had no effect on tolerance to ∆⁹-THC in female mice. The mutation did not alter tolerance to the hypothermic effects of ∆⁹-THC or CP55,940 in either sex. Interestingly, female mice were markedly less sensitive to the antinociceptive effects of 30 mg/kg ∆⁹-THC and 0.3 mg/kg CP55,940 compared with male mice.

CONCLUSIONS

Our results suggest that disruption of the GRK/βarrestin2 pathway of desensitization alters tolerance to Δ⁹-THC but not CP55,940 in male but not female mice. As tolerance to Δ⁹-THC appears to develop differently in males and females, sex should be considered when assessing the therapeutic potential and dependence liability of cannabinoids.

Sex differences in the acute effects of intravenous (IV) delta-9 tetrahydrocannabinol (THC)

BACKGROUND

Cannabis is the most common illicit drug used in the USA and its use has been rising over the past decade, while the historical gap in rates of use between men and women has been decreasing. Sex differences in the effects of cannabinoids have been reported in animal models, but human studies are sparse and inconsistent. We investigated the sex differences in the acute subjective, psychotomimetic, cognitive, and physiological effects of intravenous (IV) delta-9 tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis.

METHODS

Healthy male and female individuals, with limited exposure to cannabis, participated in a double blind, placebo-controlled study of intravenous (IV) placebo or THC at two doses (0.015 mg/kg and 0.03 mg/kg). Visual analog scale (VAS) was used to measure subjective effects, Psychotomimetic States Inventory (PSI) and the Clinician-Administered Dissociative Symptoms Scale (CADSS) were used to assess the psychotomimetic effects and perceptual alterations, respectively, and Rey Auditory Verbal Learning Task (RAVLT) was used to evaluate cognitive effects. Outcome variables were represented as the peak change from baseline for each variable, except RAVLT which was used only once per the test day after the subjective effects.

RESULTS

A total of 42 individuals participated in this study. There were no significant differences between male and female participants in background characteristics. There was a significant main effect of sex on the VAS scores for THC-induced "High" (F1,38 = 4.27, p < 0.05) and a significant dose × sex interaction (F2,77 = 3.38, p < 0.05) with female participants having greater "High" scores than male participants at the lower THC dose (0.015 mg/kg). No other sex differences were observed in acute subjective, psychotomimetic, cognitive, or physiological effects of THC.

CONCLUSION

There were significant sex differences in subjective effects of feeling "High" at a lower dose of THC. However, there were no other sex-related differences in the subjective, physiological, or cognitive effects of THC.

Sex differences in acute cannabis effects revisited: Results from two randomized, controlled trials

Some evidence suggests that males and females may differ in their responses to acute cannabis effects, including subjective drug effects and behavioural effects, and cannabinoid pharmacokinetics. This is significant given current changes to cannabis-related policies and, in consequence, increased cannabis accessibility. The present study combines data from two randomized controlled trials to investigate possible differences among males (n = 21) and females (n = 19) in the acute effects of vaporized cannabis containing 13.75 mg Δ9-tetrahydrocannabinol (THC), with and without cannabidiol (CBD; 13.75 mg). To control for differences in the timing of assessments, peak (or peak change from baseline) scores were calculated for a range of measures including subjective drug effects, cognitive performance, cardiovascular effects, and plasma concentrations of THC, CBD, and their respective primary metabolites. While THC elicited robust and significant changes in all but one outcome measure relative to placebo, relatively few sex differences were observed after controlling for BMI and plasma THC concentrations. Relative to females, males performed better overall on a divided attention task (DAT) and had higher peak plasma concentrations of 11-nor-9-carboxy-THC (11-COOH-THC). Males and females did not differ with respect to plasma concentrations of any other analyte, subjective drug effects, or cardiovascular measures. These data indicate an absence of systematic sex differences in acute cannabis effects given a moderate dose of vaporized cannabis. They do not preclude the possibility that sex differences may emerge with higher THC doses or with other commonly used routes of administration (e.g., orally administered oils or edibles).

Wonder or evil?: Multifaceted health hazards and health benefits of Cannabis sativa and its phytochemicals

Cannabis sativa, widely known as 'Marijuana' poses a dilemma for being a blend of both good and bad medicinal effects. The historical use of Cannabis for both medicinal and recreational purposes suggests it to be a friendly plant. However, whether the misuse of Cannabis and the cannabinoids derived from it can hamper normal body physiology is a focus of ongoing research. On the one hand, there is enough evidence to suggest that misuse of marijuana can cause deleterious effects on various organs like the lungs, immune system, cardiovascular system, etc. and also influence fertility and cause teratogenic effects. However, on the other hand, marijuana has been found to offer a magical cure for anorexia, chronic pain, muscle spasticity, nausea, and disturbed sleep. Indeed, most recently, the United Nations has given its verdict in favour of Cannabis declaring it as a non-dangerous narcotic. This review provides insights into the various health effects of Cannabis and its specialized metabolites and indicates how wise steps can be taken to promote good use and prevent misuse of the metabolites derived from this plant.

Impact of Acute and Chronic Cannabis Use on Stress Response Regulation: Challenging the Belief That Cannabis Is an Effective Method for Coping

Although research has only recently started to examine the impact of cannabis use on stress response, there is some evidence that indicates acute and chronic impacts of cannabis on these processes. In this paper, we review processes involved in regulating the stress response and we review the influence of acute and chronic exposure to cannabis on patterns and regulation of the stress response. We also highlight the role of stress as a risk factor for initiation and maintenance of cannabis use. In this context, we examine moderating variables, including sex and life adversity. In light of recent observations indicating increasing prevalence of cannabis use during pregnancy, we provide additional focus on cannabis use in this vulnerable population, including how acute and chronic stress may predispose some individuals to use cannabis during pregnancy. While this line of research is in its infancy, we review available articles that focus on the perinatal period and that examined the association between cannabis use and various life stressors, including partner violence, job loss, and lack of housing. We also review psychiatric co-morbidities (e.g., post-traumatic stress disorder, anxiety). A better understanding of the way stress and cannabis use relate within the general population, as well as within certain subgroups that may be at a greater risk of using and/or at greater risk for adverse outcomes of use, may lead to the development of novel prevention and intervention approaches.

Sex differences in the acute effects of oral and vaporized cannabis among healthy adults

Policy changes have increased access to cannabis for individuals with little or no prior exposure. Few studies have examined sex differences in cannabis effects among individuals with sporadic cannabis use or for nonsmoked routes of cannabis administration. Data from four double-blind, placebo-controlled studies were pooled to compare the acute pharmacodynamic effects of vaporized and oral cannabis in male (n = 27) and female (n = 23) participants who used cannabis infrequently (no use ≥30 days prior to randomization). Analyses compared peak change-from-baseline scores between male and female participants for subjective drug effects, cognitive/psychomotor performance, cardiovascular effects, and blood concentrations of Δ9-tetrahydrocannabinol (THC) and its primary metabolites (11-OH-THC, THC-COOH) after exposure to placebo cannabis or cannabis containing low-dose (5 or 10 mg) or high-dose THC (20 or 25 mg). Overall, cannabis elicited dose-orderly increases in subjective effects, impairment of cognitive/psychomotor performance, heart rate, and blood cannabinoid concentrations. Females exhibited greater peak blood 11-OH-THC concentrations and reported greater peak subjective ratings of "drug effect" that remained when controlling for body weight. When controlling for both body weight and peak blood cannabinoid concentrations, ratings of "anxious/nervous," "heart racing," and "restless" were significantly higher for females than males. Although additional research is needed to elucidate sex differences in responses to cannabis at a wider range of THC doses, other routes of administration, and products with diverse chemical composition, the current data indicate that public health messaging and clinical decision making around the use of cannabinoids should recommend lower starting doses for females and warnings about acute anxiogenic reactions.

Investigating sex differences in acute intoxication and verbal memory errors after ad libitum cannabis concentrate use

BACKGROUND

An innovative naturalistic at-home administration procedure was used to investigate sex differences in subjective drug effects and verbal memory errors after ad libitum use of high potency state legal market Δ9-tetrahydrocannabinol (THC) concentrate.

METHODS

Regular concentrate users were randomly assigned to ad libitum administration of one of two cannabis concentrate products (70 % or 90 % THC) that they purchased from a dispensary. 65 participants (N = 34 men, N = 31 women) were assessed in a mobile pharmacology lab before, immediately after, and 1 -h after ad libitum concentrate use. Plasma cannabinoids (THC, 11-OH-THC, CBD), subjective drug effects, and verbal memory errors were assessed at all three time points.

RESULTS

Although men and women exhibited similar plasma 11-OH-THC levels across time (p = .10), sex differences were found in plasma THC and CBD after legal market concentrate use, with men displaying significantly higher levels of plasma THC and CBD immediately after cannabis concentrate use (plasma THC [ng/mL]: M_men = 489.88, M_women = 135.08, p < .001; plasma CBD [ng/mL]: M_men = 1.14, M_women = 0.53, p = .04). Despite this, sex differences in subjective effects and verbal memory errors did not emerge, although women reported a steeper decrease in drug liking after use (p = .04).

CONCLUSION

These data provide the first look at sex differences after acute naturalistic cannabis concentrate use, and suggest much higher THC exposure in men versus women, but similar acute drug and impairment effects across the sexes. Further studies are needed to determine the mechanisms (e.g. tolerance, cannabinoid metabolism, smoking topography) behind these findings.

'Standard THC units': a proposal to standardize dose across all cannabis products and methods of administration

BACKGROUND AND AIMS

Cannabis products are becoming increasingly diverse, and vary considerably in concentrations of ∆⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD). Higher doses of THC can increase the risk of harm from cannabis, while CBD may partially offset some of these effects. Lower Risk Cannabis Use Guidelines currently lack recommendations based on quantity of use, and could be improved by implementing standard units. However, there is currently no consensus on how units should be measured or standardized among different cannabis products or methods of administration.

ARGUMENT

Existing proposals for standard cannabis units have been based on specific methods of administration (e.g. joints) and these may not capture other methods, including pipes, bongs, blunts, dabbing, vaporizers, vape pens, edibles and liquids. Other proposals (e.g. grams of cannabis) cannot account for heterogeneity in THC concentrations among different cannabis products. Similar to alcohol units, we argue that standard cannabis units should reflect the quantity of primary active pharmacological constituents (dose of THC). On the basis of experimental and ecological data, public health considerations and existing policy, we propose that a 'standard THC unit' should be fixed at 5 mg THC for all cannabis products and methods of administration. If supported by sufficient evidence in future, consumption of standard CBD units might offer an additional strategy for harm reduction.

CONCLUSIONS

Standard ∆⁹ -tetrahydrocannabinol (THC) units can potentially be applied among all cannabis products and methods of administration to guide consumers and promote safer patterns of use.

Sex differences in the acute effects of smoked cannabis: evidence from a human laboratory study of young adults

RATIONALE

Animal studies have found robust sex differences in the pharmacokinetics and pharmacodynamics of Δ⁹-tetrahydrocannabinol (THC). However, the human evidence remains equivocal, despite findings that women may experience more severe consequences of cannabis use than men.

OBJECTIVES

The objective of this secondary analysis was to examine sex differences in THC pharmacokinetics and in acute subjective, physiological, and cognitive effects of smoked cannabis in a sample of regular cannabis users (use 1-4 days per week) aged 19-25 years.

METHODS

Ninety-one healthy young adults were randomized to receive active (12.5% THC; 17 females, 43 males) or placebo (< 0.1% THC; 9 females, 21 males) cannabis using a 2:1 allocation ratio. Blood samples to quantify concentrations of THC, 11-OH-THC, and 11-Nor-carboxy-THC (THC-COOH), as well as measures of subjective drug effects, vital signs, and cognition were collected over a period of 6 h following ad libitum smoking of a 750-mg cannabis cigarette.

RESULTS

Females smoked less of the cannabis cigarette than males (p = 0.008) and had a lower peak concentration of THC and THC-COOH than males (p ≤ 0.01). Blood THC concentrations remained lower in females even when adjusting for differences in estimated dose of THC inhaled. There was very little evidence of sex differences in visual analog scale (VAS) ratings of subjective drug effects, mood, heart rate, blood pressure, or cognitive effects of cannabis.

CONCLUSIONS

Females experienced the same acute effects of smoked cannabis as males at a lower observed dose, highlighting the need for more research on sex differences in the pharmacology of THC, especially when administered by routes in which titrating to the desired effect is more difficult (e.g., cannabis edibles).

Interaction of Cannabis Use and Aging: From Molecule to Mind

Given the aging Baby Boomer generation, changes in cannabis legislation, and the growing acknowledgment of cannabis for its therapeutic potential, it is predicted that cannabis use in the older population will escalate. It is, therefore, important to determine the interaction between the effects of cannabis and aging. The aim of this report is to describe the link between cannabis use and the aging brain. Our review of the literature found few and inconsistent empirical studies that directly address the impact of cannabis use on the aging brain. However, research focused on long-term cannabis use points toward cumulative effects on multimodal systems in the brain that are similarly affected during aging. Specifically, the effects of cannabis and aging converge on overlapping networks in the endocannabinoid, opioid, and dopamine systems that may affect functional decline particularly in the hippocampus and prefrontal cortex, which are critical areas for memory and executive functioning. To conclude, despite the limited current knowledge on the potential interactive effects between cannabis and aging, evidence from the literature suggests that cannabis and aging effects are concurrently present across several neurotransmitter systems. There is a great need for future research to directly test the interactions between cannabis and aging.

Cannabinoid interventions for PTSD: Where to next?

Cannabinoids are a promising method for pharmacological treatment of post-traumatic stress disorder (PTSD). Despite considerable research devoted to the effect of cannabinoid modulation on PTSD symptomology, there is not a currently agreed way by which the cannabinoid system should be targeted in humans. In this review, we present an overview of recent research identifying neurological pathways by which different cannabinoid-based treatments may exert their effects on PTSD symptomology. We evaluate the strengths and weaknesses of each of these different approaches, including recent challenges presented to favourable options such as fatty acid amide hydrolase (FAAH) inhibitors. This article makes the strengths and challenges of different potential cannabinoid treatments accessible to psychological researchers interested in cannabinoid therapeutics and aims to aid selection of appropriate tools for future clinical trials.

Impact of co-administration of oxycodone and smoked cannabis on analgesia and abuse liability

Cannabinoids combined with opioids produce synergistic antinociceptive effects, decreasing the lowest effective antinociceptive opioid dose (i.e., opioid-sparing effects) in laboratory animals. Although pain patients report greater analgesia when cannabis is used with opioids, no placebo-controlled studies have assessed the direct effects of opioids combined with cannabis in humans or the impact of the combination on abuse liability. This double-blind, placebo-controlled, within-subject study determined if cannabis enhances the analgesic effects of low dose oxycodone using a validated experimental model of pain and its effects on abuse liability. Healthy cannabis smokers (N = 18) were administered oxycodone (0, 2.5, and 5.0 mg, PO) with smoked cannabis (0.0, 5.6% Δ⁹ tetrahydrocannabinol [THC]) and analgesia was assessed using the Cold-Pressor Test (CPT). Participants immersed their hand in cold water (4 °C); times to report pain (pain threshold) and withdraw the hand from the water (pain tolerance) were recorded. Abuse-related effects were measured and effects of oxycodone on cannabis self-administration were determined. Alone, 5.0 mg oxycodone increased pain threshold and tolerance (p ≤ 0.05). Although active cannabis and 2.5 mg oxycodone alone failed to elicit analgesia, combined they increased pain threshold and tolerance (p ≤ 0.05). Oxycodone did not increase subjective ratings associated with cannabis abuse, nor did it increase cannabis self-administration. However, the combination of 2.5 mg oxycodone and active cannabis produced small, yet significant, increases in oxycodone abuse liability (p ≤ 0.05). Cannabis enhances the analgesic effects of sub-threshold oxycodone, suggesting synergy, without increases in cannabis's abuse liability. These findings support future research into the therapeutic use of opioid-cannabinoid combinations for pain.

Open-label pilot study of injectable naltrexone for cannabis dependence

BACKGROUND

There are no FDA-approved pharmacotherapies for cannabis use disorders (CUD), despite the evaluation of numerous medications. Notably, chronic dosing of oral naltrexone decreases self-administration of cannabis in human laboratory studies.

OBJECTIVES

To test the feasibility of long-acting injectable naltrexone for the treatment of CUD, while obtaining preliminary safety and efficacy data.

METHODS

Twelve adult participants (seven male) meeting DSM-IV-TR criteria for cannabis dependence enrolled into an 8-week, open-label pilot study conducted at an academic treatment research clinic. They received 380 mg intramuscular injections of long-acting naltrexone on study day 1 and at the start of study week 5. Outcome measures included percentages of study completers and participants who received the second injection, frequency of adverse events (AEs), and cannabis consumption measured by average daily grams, dollars, and using days per week as measured by timeline follow-back and urine oral delta-9-tetrahydrocannabinol (THC) concentrations.

RESULTS

Of the 12 participants enrolled in the study, 9 completed the study and 6 received the second injection. There were no severe AEs but an unexpected AE led to the addition of supportive medications to the protocol. Number of cannabis use days per week significantly decreased over the course of the study (p = .001). Creatinine-corrected urine THC concentrations and average daily cannabis use per study week in grams and in dollars did not decrease over the course of the study.

CONCLUSIONS

Long-acting injectable naltrexone is a feasible intervention for CUD worthy of further study in a placebo-controlled, double-blinded randomized clinical trial.

A Systematic Review and Meta-Analysis of the In Vivo Haemodynamic Effects of Δ⁸-Tetrahydrocannabinol

∆⁹-Tetrahydrocannabinol (THC) has complex effects on the cardiovascular system. We aimed to systematically review studies of THC and haemodynamic alterations. PubMed, Medline, and EMBASE were searched for relevant studies. Changes in blood pressure (BP), heart rate (HR), and blood flow (BF) were analysed using the Cochrane Review Manager Software. Thirty-one studies met the eligibility criteria. Fourteen publications assessed BP (number, n = 541), 22 HR (n = 567), and 3 BF (n = 45). Acute THC dosing reduced BP and HR in anaesthetised animals (BP, mean difference (MD) −19.7 mmHg, p < 0.00001; HR, MD −53.49 bpm, p < 0.00001), conscious animals (BP, MD −12.3 mmHg, p = 0.0007; HR, MD −30.05 bpm, p < 0.00001), and animal models of stress or hypertension (BP, MD −61.37 mmHg, p = 0.03) and increased cerebral BF in murine stroke models (MD 32.35%, p < 0.00001). Chronic dosing increased BF in large arteries in anaesthetised animals (MD 21.95 mL/min, p = 0.05) and reduced BP in models of stress or hypertension (MD −22.09 mmHg, p < 0.00001). In humans, acute administration increased HR (MD 8.16 bpm, p < 0.00001). THC acts differently according to species and experimental conditions, causing bradycardia, hypotension and increased BF in animals; and causing increased HR in humans. Data is limited, and further studies assessing THC-induced haemodynamic changes in humans should be considered.

Sex-Dependent Effects of Cannabis and Cannabinoids: A Translational Perspective

Recent policy changes have led to significant increases in the use of cannabis for both medical and recreational purposes. Although men are more likely to endorse past month cannabis use and are more frequently diagnosed with Cannabis Use Disorder relative to women, a growing proportion of medical cannabis users are reported to be women. The increased popularity of cannabis for medical purposes and the narrowing gap in prevalence of use between men and women raises questions regarding sex-dependent effects related to therapeutic efficacy and negative health effects of cannabis and cannabinoids. The objective of this review is to provide a translational perspective on the sex-dependent effects of cannabis and cannabinoids by synthesizing findings from preclinical and clinical studies focused on sex comparisons of their therapeutic potential and abuse liability, two specific areas that are of significant public health relevance. Hormonal and pharmacological mechanisms that may underlie sex differences in the effects of cannabis and cannabinoids are highlighted.

Preclinical Studies of Cannabinoid Reward, Treatments for Cannabis Use Disorder, and Addiction-Related Effects of Cannabinoid Exposure

Cannabis use has become increasingly accepted socially and legally, for both recreational and medicinal purposes. Without reliable information about the effects of cannabis, people cannot make informed decisions regarding its use. Like alcohol and tobacco, cannabis can have serious adverse effects on health, and some people have difficulty discontinuing their use of the drug. Many cannabis users progress to using and becoming addicted to other drugs, but the reasons for this progression are unclear. The natural cannabinoid system of the brain is complex and involved in many functions, including brain development, reward, emotion, and cognition. Animal research provides an objective and controlled means of obtaining information about: (1) how cannabis affects the brain and behavior, (2) whether medications can be developed to treat cannabis use disorder, and (3) whether cannabis might produce lasting changes in the brain that increase the likelihood of becoming addicted to other drugs. This review explains the tactics used to address these issues, evaluates the progress that has been made, and offers some directions for future research.

Sex and gender differences in substance use disorders

The gender gap in substance use disorders (SUDs), characterized by greater prevalence in men, is narrowing, highlighting the importance of understanding sex and gender differences in SUD etiology and maintenance. In this critical review, we provide an overview of sex/gender differences in the biology, epidemiology and treatment of SUDs. Biological sex differences are evident across an array of systems, including brain structure and function, endocrine function, and metabolic function. Gender (i.e., environmentally and socioculturally defined roles for men and women) also contributes to the initiation and course of substance use and SUDs. Adverse medical, psychiatric, and functional consequences associated with SUDs are often more severe in women. However, men and women do not substantively differ with respect to SUD treatment outcomes. Although several trends are beginning to emerge in the literature, findings on sex and gender differences in SUDs are complicated by the interacting contributions of biological and environmental factors. Future research is needed to further elucidate sex and gender differences, especially focusing on hormonal factors in SUD course and treatment outcomes; research translating findings between animal and human models; and gender differences in understudied populations, such as those with co-occurring psychiatric disorders and gender-specific populations, such as pregnant women.

Mechanisms Underlying Sex Differences in Cannabis Use

Purpose of the Review

Cannabis is the most commonly used illicit substance worldwide. In recent decades, highly concentrated products have flooded the market, and prevalence rates have increased. Gender differences exist in cannabis use, as men have higher prevalence of both cannabis use and cannabis use disorder (CUD), while women progress more rapidly from first use to CUD. This paper reviews findings from preclinical and human studies examining the sex-specific neurobiological underpinnings of cannabis use and CUD, and associations with psychiatric symptoms.

Recent Findings

Sex differences exist in the endocannabinoid system, in cannabis exposure effects on brain structure and function, and in the co-occurrence of cannabis use with symptoms of anxiety, depression and schizophrenia. In female cannabis users, anxiety symptoms correlate with larger amygdala volume and social anxiety disorder symptoms correlate with CUD symptoms. Female cannabis users are reported to be especially vulnerable to earlier onset of schizophrenia, and mixed trends emerge in the correlation of depressive symptoms with cannabis exposure in females and males.

Summary

As prevalence of cannabis use may continue to increase given the shifting policy landscape regarding marijuana laws, understanding the neurobiological mechanisms of cannabis exposure in females and males is key. Examining these mechanisms may help inform future research on sex-specific pharmacological and behavioral interventions for women and men with high-risk cannabis use, comorbid psychiatric disease, and CUD.

Impact of synthetic cannabinoids on the duration of opioid-related withdrawal and craving among patients of addiction clinics in Kazakhstan: A prospective case-control study

OBJECTIVE

The aim of the study was to prospectively assess whether regular use of synthetic cannabinoids (SCs) affects the duration of opioid-related withdrawal and craving symptoms in patients undergoing drug detoxification treatments.

METHODS

Patients (n = 193) with opioid use disorder, among which 47 patients are regularly using SCs, underwent integrated drug detoxification therapies. The Clinical Opiate Withdrawal Scale and a specific visual analogue scale were used to assess opioid withdrawal and craving symptoms over time.

RESULTS

Subjects using SCs had significantly longer duration of withdrawal and craving symptoms (p < .001). Higher intake of SCs in the last 30 days (p = .045), shorter time since the last intake of SCs (p = .033), longer duration of SCs use (p < .001), and higher dosage of SCs (p < .001) were associated with longer duration of symptoms.

DISCUSSION

This is the first study to assess the impact of SCs on the course of opioid withdrawal and craving symptoms. The results (a) suggest that patients with opioid use disorder in combination with regular use of SCs exhibit a significantly longer duration of opioid withdrawal and craving symptoms, (b) add to the accumulating evidence showing clinical and molecular cross talks between cannabinoids and opioids, and (c) underline novel harmful effects of SCs.

Effects of daily delta-9-tetrahydrocannabinol treatment on heroin self-administration in rhesus monkeys

Opioid abuse remains a significant public health problem; together with the greater availability of marijuana in some regions there is an increasing likelihood that opioids and marijuana will be used together. Polydrug abuse is associated with increased toxicity and poorer treatment outcome; thus, a better understanding of the consequences of repeated coadministration of these drugs will facilitate the development of better prevention and treatment strategies. This study examined the effects of daily treatment with the cannabinoid receptor agonist delta-9-tetrahydrocannabinol (Δ-THC) and its discontinuation on self-administration of heroin in rhesus monkeys (n=4) lever-pressing under a fixed-ratio 30 schedule. Heroin self-administration (0.32-32 μg/kg/infusion, intravenously) generated an inverted U-shaped dose-effect curve. Administered acutely, Δ-THC (0.01-0.32 mg/kg, subcutaneously) dose dependently decreased responding for heroin and flattened the self-administration dose-effect curve. Daily treatment with Δ-THC (0.01-0.1 mg/kg/12 h, subcutaneously) either had no effect on or decreased responding for heroin. In addition, daily treatment did not significantly impact extinction of heroin self-administration or resumption of responding for heroin after extinction. Discontinuation of daily Δ-THC treatment did not systematically impact rates of heroin self-administration. These data suggest that repeated administration of a cannabinoid receptor agonist likely does not increase, and possibly decreases, the positive reinforcing effects of a mu opioid receptor agonist.

Tasty THC: Promises and Challenges of Cannabis Edibles

Food products containing cannabis extract (edibles) have emerged as a popular and lucrative facet of the legalized market for both recreational and medicinal cannabis. The many formulations of cannabis extracts used in edibles present a unique regulatory challenge for policy makers. Though edibles are often considered a safe, discreet, and effective means of attaining the therapeutic and/or intoxicating effects of cannabis without exposure to the potentially harmful risks of cannabis smoking, little research has evaluated how ingestion differs from other methods of cannabis administration in terms of therapeutic efficacy, subjective effects, and safety. The most prominent difference between ingestion and inhalation of cannabis extracts is the delayed onset of drug effect with ingestion. Consumers often do not understand this aspect of edible use and may consume a greater than intended amount of drug before the drug has taken effect, often resulting in profoundly adverse effects. Written for the educated layperson and for policy makers, this paper explores the current state of research regarding edibles, highlighting the promises and challenges that edibles present to both users and policy makers, and describes the approaches that four states in which recreational cannabis use is legal have taken regarding regulating edibles.

Are Alcohol Anti-relapsing and Alcohol Withdrawal Drugs Useful in Cannabinoid Users?

Cannabinoids are still classified as illegal psychoactive drugs despite their broad and increasingly acknowledged therapeutic potential. These substances are most famous for their wide recreational use, particularly among young adults to either alter the state of consciousness, intensify pleasure induced by other psychoactive substances or as an alternative to the previously abused drugs. It is important to emphasize that cannabinoids are often taken together with a variety of medications intended for the treatment of alcohol use disorder (AUD) or alcohol withdrawal syndrome (AWS). These medications include disulfiram, acamprosate, and naltrexone. In this paper, we summarize recent advances in the knowledge of possible beneficial effects and interactions between cannabinoids and drugs commonly used for treatment of AUD and AWS either comorbid or existing as a separate disorder.

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users

Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users.

Methods: A large sample (n=2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy.

Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial.

Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes.

Progress toward pharmacotherapies for cannabis-use disorder: an evidence-based review

Cannabis is the most widely used and variably regulated drug in the world, with increasing trends of use being reported in the US, Australia, Asia, and Africa. Evidence has shown a decrease in the age of commencement of cannabis use in some developed countries and a prolongation of risk of initiation to cannabis use beyond adolescence among more recent users. Cannabis use is associated with numerous health risks and long-term morbidity, as well as risk of developing cannabis-use disorders. Cannabis users infrequently seek professional treatment, and normally do so after a decade of use. Cannabis-use disorders are currently treated using a selection of psychosocial interventions. Severity of withdrawal is a factor that increases the risk of relapse, and is the target of pharmacotherapy studies. Currently, there is no approved pharmacotherapy for cannabis-use disorders. A number of approaches have been examined, and trials are continuing to find a safe and effective medication with little abuse liability.

Preclinical studies on the reinforcing effects of cannabinoids. A tribute to the scientific research of Dr. Steve Goldberg

RATIONALE

The reinforcing effects of most abused drugs have been consistently demonstrated and studied in animal models, although those of marijuana were not, until the demonstration 15 years ago that delta-9-tetrahydrocannabinol (THC) could serve as a reinforcer in self-administration (SA) procedures in squirrel monkeys. Until then, those effects were inferred using indirect assessments.

OBJECTIVES

The aim of this manuscript is to review the primary preclinical procedures used to indirectly and directly infer reinforcing effects of cannabinoid drugs.

METHODS

Results will be reviewed from studies of cannabinoid discrimination, intracranial self-stimulation (ICSS), conditioned place preference (CPP), as well as change in levels of dopamine assessed in brain areas related to reinforcement, and finally from self-administration procedures. For each procedure, an evaluation will be made of the predictive validity in detecting the potential abuse liability of cannabinoids based on seminal papers, with the addition of selected reports from more recent years especially those from Dr. Goldberg's research group.

RESULTS AND CONCLUSIONS

ICSS and CPP do not provide consistent results for the assessment of potential for abuse of cannabinoids. However, drug discrimination and neurochemistry procedures appear to detect potential for abuse of cannabinoids, as well as several novel "designer cannabinoid drugs." Though after 15 years transfer of the self-administration model of marijuana abuse from squirrel monkeys to other species remains somewhat problematic, studies with the former species have substantially advanced the field, and several reports have been published with consistent self-administration of cannabinoid agonists in rodents.

Screening Medications for the Treatment of Cannabis Use Disorder

Cannabis use has been increasingly accepted legally and in public opinion. However, cannabis has the potential to produce adverse physical and mental health effects, and cannabis use disorder (CUD) occurs in a substantial percentage of both occasional and daily cannabis users. Many people have difficulty discontinuing use despite receiving treatment. Therefore, it would be beneficial to develop safe and effective medications for treating CUD. To achieve this, methods have been developed for screening and evaluating potential medications using animal models and controlled experimental protocols in human volunteers. In this chapter, we describe: (1) animal models available for assessing the effect of potential medications on specific aspects of CUD, (2) the main findings obtained so far with these animal models, (3) the approaches used to assess potential medications in humans in laboratory experiments and clinical trials, and (4) the effectiveness of several potential pharmacotherapies on particular aspects of CUD modeled in these human studies.

Does Cannabis Cause, Exacerbate or Ameliorate Psychiatric Disorders? An Oversimplified Debate Discussed

There have been extensive policy shifts in the legality of recreational and therapeutic use of cannabis in the United States, as well as a steady increase in the number of people using the drug on a regular basis. Given these rapid societal changes, defining what is known scientifically about the consequences of cannabis use on mental health takes on added public health significance. The purpose of this circumspectives piece is to discuss evidence of cannabis' effects on two psychiatric conditions: post-traumatic stress disorder and psychotic disorders. Dr Haney and Dr Evins will discuss two viewpoints regarding the benefit and harm of cannabis use for these conditions, while outlining what remains unproven and requires further testing to move the field forward.

Safety of oral dronabinol during opioid withdrawal in humans

BACKGROUND

Opioid dependence remains a significant public health problem worldwide with only three FDA-approved treatments, all targeting the mu-opioid receptor. Dronabinol, a cannabinoid (CB) 1 receptor agonist, is currently under investigation as a novel opioid withdrawal treatment. This study reports on safety outcomes of dronabinol among adults in opioid withdrawal.

METHODS

Twelve adults physically dependent on short-acting opioids participated in this 5-week within-subject, randomized, double blind, placebo-controlled inpatient study. Volunteers were maintained on oral oxycodone 30 mg qid. Double-blind placebo substitutions occurred for 21 h before each of 7 experimental sessions in order to produce opioid withdrawal. A single oral test dose was administered each session (placebo, oxycodone 30 and 60 mg, dronabinol 5, 10, 20, and 30 mg [decreased from 40 mg]). Heart rate, blood pressure, respiratory outcomes and pupil diameter were assessed repeatedly.

RESULTS

Dronabinol 40 mg produced sustained sinus tachycardia accompanied by anxiety and panic necessitating dose reduction to 30 mg. Sinus tachycardia and anxiety also occurred in one volunteer after dronabinol 20mg. Compared to placebo, dronabinol 20 and 30 mg produced significant increases in heart rate beginning 1h after drug administration that lasted approximately 2h (p<0.05). Dronabinol 5 and 10mg produced placebo-like effects. Oxycodone produced prototypic mu-opioid agonist effects (e.g., miosis).

CONCLUSION

Dronabinol 20mg and higher increased heart rate among healthy adults at rest who were in a state of opioid withdrawal, raising concern about its safety. These results have important implications for future dosing strategies and may limit the utility of dronabinol as a treatment for opioid withdrawal.

Naltrexone Maintenance Decreases Cannabis Self-Administration and Subjective Effects in Daily Cannabis Smokers

Given that cannabis use is increasing in the United States, pharmacological treatment options to treat cannabis use disorder are needed. Opioid antagonists modulate cannabinoid effects and may offer a potential approach to reducing cannabis use. In this double-blind, placebo-controlled human laboratory study, we assessed the effects of naltrexone maintenance on the reinforcing, subjective, psychomotor, and cardiovascular effects of active and inactive cannabis. Nontreatment-seeking, daily cannabis smokers were randomized to receive naltrexone (50 mg: n=18 M and 5 F) or placebo (0 mg; n=26 M and 2 F) capsules for 16 days. Before, during, and after medication maintenance, participants completed 10 laboratory sessions over 4-6 weeks, assessing cannabis' behavioral and cardiovascular effects. Medication compliance was verified by observed capsule administration, plasma naltrexone, and urinary riboflavin. Relative to placebo, maintenance on naltrexone significantly reduced both active cannabis self-administration and its positive subjective effects ('good effect'). Participants in the placebo group had 7.6 times (95% CI: 1.1-51.8) the odds of self-administering active cannabis compared with the naltrexone group. This attenuation of reinforcing and positive subjective effects also influenced cannabis use in the natural ecology. Naltrexone had intrinsic effects: decreasing ratings of friendliness, food intake, and systolic blood pressure, and increasing spontaneous reports of stomach upset and headache, yet dropout rates were comparable between groups. In summary, we show for the first time that maintenance on naltrexone decreased cannabis self-administration and ratings of 'good effect' in nontreatment-seeking daily cannabis smokers. Clinical studies in patients motivated to reduce their cannabis use are warranted to evaluate naltrexone's efficacy as a treatment for cannabis use disorder.

Cannabis and psychopathology: The meandering journey of the last decade

Since its inception cannabis has been observed to be associated with various psycho-pathology. In this paper, the authors have reviewed the advancement made in this area over the last decade. The association between cannabis and schizophrenia has been researched more intensively. The controversy regarding the reliability, clinical utility, and the existence of a cannabis withdrawal syndrome has also been settled. Recent studies also buttressed the possibility of acute and chronic effect of cannabis on various cognitive functions. There has been a plethora of research regarding the treatment for cannabis use disorders. But the new and most interesting area of research is concentrated on the endocannabinoid system and its contribution in various psychiatric disorders.

Existe-t-il des différences entre les hommes et les femmes en ce qui concerne les problèmes de toxicomanie ?

La consommation et la dépendance aux drogues furent longtemps considérées comme un problème typiquement masculin. Néanmoins, bien que l’abus et la dépendance à l’alcool, au cannabis et à la nicotine soient encore plus répandus chez les hommes, les différences de genre en ce qui concerne les stimulants et les opiacés ont largement disparu. Il semblerait également que les motivations pour commencer à consommer, l’escalade vers la dépendance et les taux de cessation diffèrent chez les hommes et les femmes. Les raisons qui expliquent ces différences sont multiples et complexes. Nous allons examiner ici les données des études épidémiologiques et cliniques concernant la consommation de diverses drogues chez des hommes et chez des femmes en contexte des facteurs socioculturels, psychologiques et neurobiologiques.

Chronic Δ⁹-tetrahydrocannabinol administration may not attenuate simian immunodeficiency virus disease progression in female rhesus macaques

Persons living with HIV/AIDS (PLWHA) frequently use cannabinoids, either recreationally by smoking marijuana or therapeutically (delta-9-tetrahydrocannabinol; Δ(9)-THC dronabinol). Previously, we demonstrated that chronic Δ(9)-THC administration decreases early mortality in male simian immunodeficiency virus (SIV)-infected macaques. In this study, we sought to examine whether similar protective effects resulted from chronic cannabinoid administration in SIV-infected female rhesus macaques. Clinical and viral parameters were evaluated in eight female rhesus macaques that received either Δ(9)-THC (0.18-0.32 mg/kg, intramuscularly, twice daily) or vehicle (VEH) starting 28 days prior to intravenous inoculation with SIVmac251. SIV disease progression was assessed by changes in body weight, mortality, viral levels in plasma and mucosal sites, and lymphocyte subsets. In contrast to our results in male animals, chronic Δ(9)-THC did not protect SIV-infected female rhesus macaques from early mortality. Markers of SIV disease, including viral load and CD4(+)/CD8(+) ratio, were not altered by Δ(9)-THC compared to control females; however, females that received chronic Δ(9)-THC did not gain as much weight as control animals. In addition, Δ(9)-THC administration increased total CXCR4 expression in both peripheral and duodenal CD4(+) and CD8(+) T lymphocytes prior to SIV inoculation. Although protection from early mortality was not evident, chronic Δ(9)-THC did not affect clinical markers of SIV disease progression. The contrasting effects of chronic Δ(9)-THC in males versus females remain to be explained, but highlight the need for further studies to explore the sex-dependent effects of Δ(9)-THC and other cannabinoids on the HIV disease course and their implications for virus transmission.

Sex differences in outcomes of methadone maintenance treatment for opioid addiction: a systematic review protocol

BACKGROUND

Use of methadone for the treatment of opioid addiction is an effective harm-reduction approach, although variability in treatment outcomes among individuals has been reported. Men and women with opioid addiction have been known to differ in factors such as opioid use patterns and characteristics at treatment entry; however, little has been reported about differences in methadone treatment outcomes between men and women. Therefore, we present a protocol for a systematic review which aims to provide a summary of existing literature on sex differences in outcomes of methadone treatment for opioid addiction.

METHODS/DESIGN

Electronic search of PubMed/MEDLINE, EMBASE, PsycINFO, and CINAHL databases will be conducted using a priori defined search strategy. Two authors (MB and BBD) will independently screen potential articles for eligibility using pre-determined inclusion and exclusion criteria and extract key information using a data extraction form designed for this study. Discrepancies will be resolved using a third party (ZS). The primary outcome will be sex differences in response to treatment defined as abstinence from illicit opioid use. We will also assess sex differences in treatment outcomes including treatment retention, remission status post-treatment, polysubstance abuse, methadone dose, drug-related adverse events, health status, psychological status, mortality, criminal activity, high risk sexual behavior, social support/relations, and employment. A meta-analysis will be conducted if possible; risk of bias and overall quality of evidence will be assessed to determine confidence in the estimates.

DISCUSSION

We anticipate that this review will highlight how men and women differ in methadone treatment outcomes and allow us to generate conclusions that can be applied to treatment in a clinical setting.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42013006549.