Category Archives: Addiction

Falling rates of marijuana dependence among heavy users.

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“Marijuana use has become increasingly popular in the United States since the turn of the century, and typical use patterns among past-month marijuana users have intensified, raising concerns for an increase in cannabis use disorders (CUDs). Yet the population prevalence of CUDs has mostly remained flat. We analyzed trends in DSM-IV marijuana dependence among Daily/Near-Daily (DND) users, both overall and by age and gender, and considered potential explanations.

RESULTS:

Dependence among DND users fell by 39% (26.5%-16.1%; p < .001), with significant trend. No significant change is detected at the population level. Sub-group analysis shows a steep gradient for age but not for gender. Declines are robust to sub-group analysis, except for users over 50 years old. Among dependence symptoms, most showed significant declines: reducing important activities (p < .001); use despite emotional, mental, or physical problems (p < .001); failing attempts to cutback (p < .001); lots of time getting, using, or getting over marijuana (p < .01); and failing to keep limits set on use (p < .05). Reported tolerance showed no significant change.

CONCLUSIONS:

Though it is unclear why, the risk of dependence formation among heavy marijuana users appear to have declined since 2002. Further research is warranted regarding explanations related to state marijuana policies, product forms, or social context.”

https://www.ncbi.nlm.nih.gov/pubmed/30077891

https://www.drugandalcoholdependence.com/article/S0376-8716(18)30389-2/fulltext

Brain activity of anandamide: a rewarding bliss?

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“Anandamide is a lipid mediator that acts as an endogenous ligand of CB1 receptors. These receptors are also the primary molecular target responsible for the pharmacological effects of Δ9-tetrahydrocannabinol, the psychoactive ingredient in Cannabis sativa.

Several studies demonstrate that anandamide exerts an overall modulatory effect on the brain reward circuitry. Several reports suggest its involvement in the addiction-producing actions of other abused drugs, and it can also act as a behavioral reinforcer in animal models of drug abuse.

Importantly, all these effects of anandamide appear to be potentiated by pharmacological inhibition of its metabolic degradation. Enhanced brain levels of anandamide after treatment with inhibitors of fatty acid amide hydrolase, the main enzyme responsible for its degradation, seem to affect the rewarding and reinforcing actions of many drugs of abuse.

In this review, we will provide an overview from a preclinical perspective of the current state of knowledge regarding the behavioral pharmacology of anandamide, with a particular emphasis on its motivational/reinforcing properties. We will also discuss how modulation of anandamide levels through inhibition of enzymatic metabolic pathways could provide a basis for developing new pharmaco-therapeutic tools for the treatment of substance use disorders.”

 https://www.ncbi.nlm.nih.gov/pubmed/30050084
https://www.nature.com/articles/s41401-018-0075-x

Cannabidiol does not display drug abuse potential in mice behavior.

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“Recent evidence suggests that cannabidiol (CBD) may be useful for the treatment of different neuropsychiatric disorders.

However, some controversy regarding its profile as a drug of abuse hampers the further development of basic and clinical studies.

In this study, the behavioral profile of CBD as a potential drug of abuse was evaluated in C57BL/6J mice.

Taken together, these results show that CBD lacks activity as a drug of abuse and should stimulate the development of the basic and clinical studies needed to elucidate its potential therapeutic use for the treatment of neuropsychiatric and drug use disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/30022153
https://www.nature.com/articles/s41401-018-0032-8

Medical Cannabis Legalization and Opioid Prescriptions: Evidence on US Medicaid Enrollees during 1993-2014.

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“While the US has been experiencing an opioid epidemic, 29 states and Washington DC have legalized cannabis for medical use. This study examined whether statewide medical cannabis legalization was associated with reduction in opioids received by Medicaid enrollees.

FINDINGS:

For Schedule III opioid prescriptions, medical cannabis legalization was associated with a 29.6% (p=0.03) reduction in number of prescriptions, 29.9% (p=0.02) reduction in dosage, and 28.8% (p=0.04) reduction in related Medicaid spending. No evidence was found to support the associations between medical cannabis legalization and Schedule II opioid prescriptions. Permitting medical cannabis dispensaries was not associated with Schedule II or Schedule III opioid prescriptions after controlling for medical cannabis legalization. It was estimated that, if all the states had legalized medical cannabis by 2014, Medicaid annual spending on opioid prescriptions would be reduced by 17.8 million dollars.

CONCLUSION:

Statewide medical cannabis legalization appears to have been associated with reductions in both prescriptions and dosages of Schedule III (but not Schedule II) opioids received by Medicaid enrollees in the US.”

https://www.ncbi.nlm.nih.gov/pubmed/29989239

https://onlinelibrary.wiley.com/doi/abs/10.1111/add.14382

Neural correlates of interactions between cannabidiol and Δ(9) -tetrahydrocannabinol in mice: implications for medical cannabis.

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BPS (Pharm)

“It has been proposed that medicinal strains of cannabis and therapeutic preparations would be safer with a more balanced concentration ratio of Δ(9) -tetrahydrocannabinol (THC) to cannabidiol (CBD), as CBD reduces the adverse psychotropic effects of THC.

The aim of this study was to investigate whether CBD modulated the functional effects and c-Fos expression induced by THC, using a 1:1 dose ratio that approximates therapeutic strains of cannabis and nabiximols.

These data confirm that CBD modulated the pharmacological actions of THC and provide new information regarding brain regions involved in the interaction between CBD and THC.”

https://www.ncbi.nlm.nih.gov/pubmed/26377899

“A number of studies now support the view that cannabidiol (CBD) may reduce the negative psychotropic effects of THC while enhancing its positive therapeutic actions. Our results are consistent with the notion that cannabis plant strains that contain THC and CBD at 1:1 ratios may be preferable to street cannabis for medicinal applications because they maximize therapeutic efficacy while minimizing the adverse effects of THC.”  https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1111/bph.13333

Reinforcing effects of opioid/cannabinoid mixtures in rhesus monkeys responding under a food/drug choice procedure.

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Psychopharmacology

“Cannabinoid receptor agonists such as delta-9-tetrahydrocannabinol (Δ9-THC) enhance the antinociceptive potency of mu opioid receptor agonists such as morphine, indicating that opioid/cannabinoid mixtures might be effective for treating pain. However, such enhancement will be beneficial only if cannabinoids do not also enhance adverse effects of opioids, including those related to abuse.

In rhesus monkeys, cannabinoids fail to enhance and often decrease self-administration of the mu opioid receptor agonist heroin, suggesting that opioid/cannabinoid mixtures do not have greater reinforcing effects (abuse potential) compared with opioids alone. Previous studies on the self-administration of opioid/cannabinoid mixtures used single-response procedures, which do not easily differentiate changes in reinforcing effects from other effects (e.g., rate decreasing).

CONCLUSION:

Overall, these results extend previous studies to include choice behavior and show that cannabinoids do not substantially enhance the reinforcing effects of mu opioid receptor agonists.”

 https://www.ncbi.nlm.nih.gov/pubmed/29860612
https://link.springer.com/article/10.1007%2Fs00213-018-4932-6

Effects of cannabidiol plus naltrexone on motivation and ethanol consumption.

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“The aim of this study was to explore if the administration of naltrexone (NTX) together with cannabidiol (CBD) may improve the efficacy in reducing alcohol consumption and motivation rather than any of the drugs given separately.

The administration of CBD + NTX significantly reduced motivation and ethanol intake in the oral self-administration procedure in a greater proportion than the drugs given alone. Only the combination of both drugs significantly reduced Oprm1, TH and 5-HT1A gene expressions in the NAc, VTA and DR, respectively. Interestingly, the administration of WAY100635 significantly blocked the actions of CBD + NTX but had no effects by itself.

CONCLUSION AND IMPLICATIONS:

The combination of low doses of CBD plus NTX resulted more effective to reduce ethanol consumption and motivation to drink. These effects, appears to be mediated, at least in part, by 5-HT1A receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/29859012

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.14380

“Naltrexone belongs to a class of drugs known as opiate antagonists. It works in the brain to prevent opiate effects (e.g., feelings of well-being, pain relief). It also decreases the desire to take opiates. This medication is also used to treat alcohol abuse. It can help people drink less alcohol or stop drinking altogether. It also decreases the desire to drink alcohol when used with a treatment program that includes counseling, support, and lifestyle changes.” https://www.webmd.com/drugs/2/drug-7399/naltrexone-oral/details

“Cannabidiol reduces ethanol consumption, motivation and relapse in mice. Taken together, these results reveal that the administration of CBD reduced the reinforcing properties, motivation and relapse for ethanol. These findings strongly suggest that CBD may result useful for the treatment of alcohol use disorders.”   https://www.ncbi.nlm.nih.gov/pubmed/28194850

Ventilatory-depressant effects of opioids alone and in combination with cannabinoids in rhesus monkeys.

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“Pain is a serious health problem that is commonly treated with opioids, although the doses of opioids needed to treat pain are often similar to those that decrease respiration. Combining opioids with drugs that relieve pain through non-opioid mechanisms can decrease the doses of opioids needed for analgesia, resulting in an improved therapeutic window, but only if the doses of opioids that decrease respiration are not similarly decreased. Using small doses of opioids to treat pain has the potential to reduce the number of overdoses and deaths.

This study investigated whether the cannabinoid receptor agonists Δ9-tetrahydrocannabinol (Δ9-THC) and CP 55,940 modify the ventilatory-depressant effects of morphine and fentanyl in three monkeys.

In summary, cannabinoid receptor agonists, which increase the potency of opioids to produce antinociception, did not increase their potency to depress ventilation. Thus, the therapeutic window is greater for opioids when they are combined with cannabinoid receptor agonists, indicating a possible advantage for these drug mixtures in treating pain.”

https://www.ncbi.nlm.nih.gov/pubmed/29807027

https://www.sciencedirect.com/science/article/pii/S0014299918303108

Computational investigation on the binding modes of Rimonabant analogues with CB1 and CB2.

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“The human cannabinoid G protein coupled receptor 1 (CB1) is highly expressed in central nervous system. CB1-selective antagonists show therapeutic promise in a wide range of disorders, such as obesity-related metabolic disorders, dyslipidemia, drug abuse and type 2 diabetes.

Rimonabant (SR141716A), MJ08 and MJ15 are selective CB1 antagonists with selectivity >1000 folds over CB2 despite of 42% sequence identity between CB1 and CB2. The integration of homology modeling, automated molecular docking and molecular dynamics simulation were used to investigate the binding modes of these selective inverse agonists/antagonists with CB1 and CB2 and their selectivity.

Our analyses showed that the hydrophobic interactions between ligands and hydrophobic pockets of CB1 account for the main binding affinity. In addition, instead of interacting with ligands directly as previously reported, the Lys1923.28in CB1 was engaged in indirect interactions with ligands to keep inactive-state CB1 stable by forming the salt bridge with Asp1762.63 . Lastly, our analyses indicated that the selectivity of these antagonists came from the difference in geometry shapes of binding pockets of CB1 and CB2.

The present study could guide future experimental works on these receptors and has the guiding significance for the design of functionally selective drugs targeting CB1 or CB2 receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/29797785

https://onlinelibrary.wiley.com/doi/abs/10.1111/cbdd.13337

Randomised Controlled Trial (RCT) of cannabinoid replacement therapy (Nabiximols) for the management of treatment-resistant cannabis dependent patients: a study protocol.

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“The cannabis extract nabiximols (Sativex®) effectively supresses withdrawal symptoms and cravings in treatment resistant cannabis dependent individuals, who have high relapse rates following conventional withdrawal treatments.

This study examines the efficacy, safety and cost-effectiveness of longer-term nabiximols treatment for outpatient cannabis dependent patients who have not responded to previous conventional treatment approaches.

This is the first outpatient community-based randomised controlled study of nabiximols as an agonist replacement medication for treating cannabis dependence, targeting individuals who have not previously responded to conventional treatment approaches. The study and treatment design is modelled upon an earlier study with this population and more generally on other agonist replacement treatments (e.g. nicotine, opioids).”

https://www.ncbi.nlm.nih.gov/pubmed/29776349

“There is a need for more effective treatment approaches for cannabis dependent patients who are unable to discontinue their illicit use through psychosocial interventions alone. Longer-term agonist replacement treatment approaches rather than acute withdrawal management are likely to be more effective, with the combination of THC:CBD nabiximols preparation being potentially advantageous over synthetic THC analogues. This is the first large-scale outpatient RCT of nabiximols for this population, and has required the development of clinical and research methods specific to agonist treatment with a plant-derived cannabinoid formulation, building upon clinical research models previously used in opioid agonist treatment approaches.”

https://bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-018-1682-2