PURPOSE: Previous studies have shown that tetrahydrocannabinol (THC), the main psychoactive component of cannabis, can impair cognitive abilities. There is also some evidence that cannabidiol (CBD), the most abundant non-intoxicating constituent of cannabis, can attenuate these effects. The purpose of this study was to investigate the effects of THC, CBD oromucosal spray (with equal parts THC and CBD) on cognition compared with control conditions in human studies.
METHODS: A systematic literature search was performed on four major bibliographic databases. Studies were included in the present review if they evaluated the cognitive effects of THC, CBD oromucosal spray compared with a control condition.
RESULTS: Ten studies were identified (7 on patients with multiple sclerosis, 1 on those with Huntington, and 2 on healthy volunteers) with 510 participants in total. There was considerable heterogeneity among the studies in terms of dose and duration of administration. All studies have used an equal or nearly equal dose of THC and CBD.
CONCLUSIONS: Although the results across studies were somewhat inconsistent, most evidence revealed that there is no significant difference between THC, CBD oromucosal spray and control treatments in terms of cognitive outcomes. However, more trials are needed with longer follow-up periods, and dose considerations, particularly comparing lower and higher doses of the spray.
BACKGROUND: Cannabis-based medicines are widely used in the treatment of a number of medical conditions. Unfortunately, cognitive disturbances are often reported as adverse events, although conversely, cognitive improvements have been reported. Hence, the objective of the present study was to identify, critically appraise and synthesise research findings on the potential impact of cannabis-based medicines on cognitive functioning.
METHODS: Four databases (EMBASE, PsycINFO, PubMed and Scopus) were systematically searched. Studies were included if they provided findings on the impact of cannabis-based medicines in controlled settings on cognitive functioning measured by recognised cognitive tests in human adults. Study participants were required to be their own case-control, and neither studies on abuse, abstinences, patients with severe neurodegenerative diseases nor cancer-related pain conditions were included. Screening, risk of bias assessment and data extraction were conducted independently by two researchers. Findings were tabulated and synthesised by outcome.
FINDINGS: Twenty-three studies were included, comprising a total of N = 917. Eight studies used Sativex as the cannabis-based medicine two used Epidiolex, two other studies used sprays, three studies used gelatine capsules, five smoked cannabis, two other and finally one studied cannabis withdrawal. Fifteen studies reported non-significant findings; six reported cognitive impairments; one study found cognitive improvement and a single study found improvement following withdrawal. Thirteen studies had cognitive or neuropsychological functioning as the primary outcome.
CONCLUSIONS: Due to a large heterogeneity and methodological limitations across studies, it is not possible to make any definite conclusions about the impact of cannabis-based medicines on cognitive functioning. However, the majority of high-quality evidence points in the direction that the negative impact of cannabis-based medicines on cognitive functioning is minor, provided that the doses of THC are low to moderate. On the other hand, long-term use of cannabis based medicines may still adversely affect cognitive functioning. In the studies that found impaired cognitive functioning to be significant, all of the test scores were either within the normal range or below what would be characterised as a neuropsychologically cognitive impairment.
Objective: To compile and synthesize the available literature describing medical cannabis use across various disease states. Data Sources: PubMed, EBSCO, and Google Scholar searches were conducted using MeSH and/or keywords. Study Selection and Data Extraction: Studies were included if they described the use of cannabis-based products and medications in the treatment of a predefined list of disease states in humans and were published in English. The extraction period had no historical limit and spanned through April 2019. Data Synthesis: Evidence was compiled and summarized for the following medical conditions: Alzheimer disease, amyotrophic lateral sclerosis, autism, cancer and cancer-associated adverse effects, seizure disorders, human immunodeficiency virus, inflammatory bowel disease, multiple sclerosis (MS), nausea, pain, posttraumatic stress disorder, and hospice care. Relevance to Patient Care and Clinical Practice: Based on identified data, the most robust evidence suggests that medical cannabis may be effective in the treatment of chemotherapy-induced nausea and vomiting, seizure disorders, MS-related spasticity, and pain (excluding diabetic neuropathy). Overall, the evidence is inconsistent and generally limited by poor quality. The large variation in cannabis-based products evaluated in studies limits the ability to make direct comparisons. Regardless of the product, a gradual dose titration was utilized in most studies. Cannabis-based therapies were typically well tolerated, with the most common adverse effects being dizziness, somnolence, dry mouth, nausea, and euphoria. Conclusions: As more states authorize medical cannabis use, there is an increasing need for high-quality clinical evidence describing its efficacy and safety. This review is intended to serve as a reference for clinicians, so that the risks and realistic benefits of medical cannabis are better understood.
Background: For patients with chronic, non-cancer pain, traditional pain-relieving medications include opioids, which have shown benefits but are associated with increased risks of addiction and adverse effects. Medical cannabis has emerged as a treatment alternative for managing these patients and there has been a rise in the number of randomized clinical trials in recent years; therefore, a systematic review of the evidence was warranted. Objective: To analyze the evidence surrounding the benefits and harms of medical cannabinoids in the treatment of chronic, non-cancer-related pain. Design: Systematic review with meta-analysis. Data sources: Medline, Embase, CINAHL, SCOPUS, Google Scholar, and Cochrane Databases. Eligibility criteria: English language randomized clinical trials of cannabinoids for the treatment of chronic, non-cancer-related pain. Data extraction and synthesis: Study quality was assessed using the Cochrane risk of bias tool. All stages were conducted independently by a team of 6 reviewers. Data were pooled through meta-analysis with different durations of treatment (2 weeks, 2 months, 6 months) and stratified by route of administration (smoked, oromucosal, oral), conditions, and type of cannabinoids. Main outcomes and measures: Patient-reported pain and adverse events (AEs). Results: Thirty-six trials (4006 participants) were included, examining smoked cannabis (4 trials), oromucosal cannabis sprays (14 trials), and oral cannabinoids (18 trials). Compared with placebo, cannabinoids showed a significant reduction in pain which was greatest with treatment duration of 2 to 8 weeks (weighted mean difference on a 0-10 pain visual analogue scale −0.68, 95% confidence interval [CI], −0.96 to −0.40, I2 = 8%, P <.00001; n = 16 trials). When stratified by route of administration, pain condition, and type of cannabinoids, oral cannabinoids had a larger reduction in pain compared with placebo relative to oromucosal and smoked formulations but the difference was not significant (P[interaction] >.05 in all the 3 durations of treatment); cannabinoids had a smaller reduction in pain due to multiple sclerosis compared with placebo relative to other neuropathic pain (P[interaction] =.05) within 2 weeks and the difference was not significant relative to pain due to rheumatic arthritis; nabilone had a greater reduction in pain compared with placebo relative to other types of cannabinoids longer than 2 weeks of treatment but the difference was not significant (P[interaction] >.05). Serious AEs were rare, and similar across the cannabinoid (74 out of 2176, 3.4%) and placebo groups (53 out of 1640, 3.2%). There was an increased risk of non-serious AEs with cannabinoids compared with placebo. Conclusions: There was moderate evidence to support cannabinoids in treating chronic, non-cancer pain at 2 weeks. Similar results were observed at later time points, but the confidence in effect is low. There is little evidence that cannabinoids increase the risk of experiencing serious AEs, although non-serious AEs may be common in the short-term period following use.
There is growing interest in using cannabinoids for chronic pain. We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain. PubMed, EMBASE, Web of Science, Cochrane CENTRAL and clinicaltrials.gov were searched up to December 2018. Information on the type, dosage, route of administration, pain conditions, pain scores, and adverse events were extracted for qualitative analysis. Meta-analysis of analgesic efficacy was performed. Meta-regression was performed to compare the analgesic efficacy for different pain conditions (neuropathic versus non-neuropathic pain). Risk of bias was assessed by The Cochrane Risk of Bias tool, and the strength of the evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Forty-three randomized controlled trials were included. Meta-analysis was performed for 33 studies that compared cannabinoids to placebo, and showed a mean pain score (scale 0-10) reduction of -0.70 (p < 0.001, random effect). Meta-regression showed that analgesic efficacy was similar for neuropathic and non-neuropathic pain (Difference = -0.14, p = 0.262). Inhaled, oral, and oromucosal administration all provided statistically significant, but small reduction in mean pain score (-0.97, -0.85, -0.45, all p < 0.001). Incidence of serious adverse events was rare, and non-serious adverse events were usually mild to moderate. Heterogeneity was moderate. The GRADE level of evidence was low to moderate. Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption, but effect sizes were small. Efficacy for neuropathic and non-neuropathic pain was similar.
Indications of cannabis use are numerous although the indication to relief pain remains a major research interest and clinical application. Studies investigating the effect of herbal cannabis and cannabis-based medicine on neuropathic, non-neuropathic pain, acute pain and experimentally induced pain were reviewed. A search was performed in PubMed and Cochrane library for articles published in English between January 1, 2000 and May 8, 2020. The search terms used were related to cannabis and pain in adults. We identified 34 studies, of which 30 were randomized controlled clinical trials (RCTs). Varying effects were identified from the RCTs, and as expected more promising effects from non-RCTs. Cannabis-based medications were found most effective as an adjuvant therapy in refractory multiple sclerosis, and weak evidence was found to support the treatment of cancer pain especially in advanced stages. Chronic rheumatic pain showed promising results. Adverse events of cannabis-based treatment were found to be more frequent with tetrahydrocannabinol herbal strains compared to other cannabis-derived products.
OBJECTIVES: To determine the effects of cannabis, cannabinoids, and their administration routes on pain and adverse euphoria events.
DATA SOURCES: A systematic search was performed in PubMed, ScienceDirect, ClincalTrials.gov, Scopus, Cochrane Library, and Embase from inception until June 2017.
STUDY SELECTION: Randomized controlled trials investigating the effects of cannabis or cannabinoids on pain reduction.
DATA EXTRACTION: Two reviewers extracted and assessed the quality of studies by means of Cochrane risk of bias. Standardized mean difference (SMD) was calculated. Random-effects model was undertaken to pool the treatment effects.
RESULTS: A total of 25 studies involving 2270 patients were included. We found that delta-9-tetrahydrocannabinol/cannabidiol (THC/CBD) (oromucosal route), THC (oromucosal route), and standardized dried cannabis (with THC; SCT; inhalation route) could reduce neuropathic pain score (SMD -0.41, 95% CI -0.7 to -0.1; -0.61, 95% CI -1.2 to -0.02; and -0.77, 95% CI -1.4 to -0.2; respectively). For nociceptive pain, only standardized cannabis extract (with THC; SCET) via oral route could reduce pain score (SMD -1.8, 95% C; -2.4 to -1.2). In cancer pain, THC/CBD via oromucosal route and THC via oral or oromucosal route could reduce pain score (SMD -0.7, 95% CI -1.2 to -0.2; and -2.1, 95% CI -2.8 to -1.4; respectively). No study was observed for THC/CBD via oral route or inhalation or THC via inhalation for cancer and nociceptive pain, SCET via oromucosal route or inhalation for neuropathic and cancer pain, THC via oromucosal route for nociceptive pain, and SCT via oromucosal or oral route for neuropathic, cancer, and nociceptive pain. Statistically significant increased risks of euphoria were observed in THC/CBD (oromucosal), THC (oromucosal), and SCT (inhalation).
CONCLUSION: The use of cannabis and cannabinoids via certain administration routes could reduce different types of pain. Product developers could consider our findings as part of their product design so that the effective route of cannabis and cannabinoids for pain control can be achieved.
Background: Pain is the most frequent indication for which medical cannabis treatment is sought.Objectives: The clinical potential of cannabis and cannabis-derived products (CDPs) relies on their efficacy to treat an indication and potential adverse effects that impact outcomes, including abuse liability and neurocognitive effects. To ascertain the extent to which these effects impact therapeutic utility, studies investigating cannabis and CDPs for pain were reviewed for analgesic efficacy and assessments of abuse liability and neurocognitive effects.Methods: A comprehensive review of placebo-controlled studies investigating cannabis and CDP analgesia was performed. Methods and findings related to adverse effects, abuse liability, and neurocognitive effects were extracted.Results: Thirty-eight studies were reviewed; 29 assessed cannabis and CDPs for chronic pain, 1 for acute pain, and 8 used experimental pain tests. Most studies ascertained adverse effects through self-report (N = 27). Fewer studies specifically probed abuse liability (N = 7) and cognitive and psychomotor effects (N = 12). Many studies related to chronic and experimental pain (N = 18 and N = 5, respectively) found cannabis and CDPs to reduce pain. Overall, adverse effects were mild to moderate, and dose-related. Studies investigating the impact of cannabis and CDPs on abuse liability and neurocognitive endpoints were mostly limited to inhaled administration and confirmed dose-related effects.Conclusion: Few studies investigating cannabis and CDP analgesia assess abuse liability and cognitive endpoints, adverse effects that impact the long-term clinical utility of these drugs. Future studies should include these measures to optimize research and clinical care related to cannabis-based therapeutics.
Cannabis and its pharmacologically active constituents, phytocannabinoids, have long been reported to have multiple medicinal benefits. One association often reported by users is sedation and subjective improvements in sleep. To further examine this association, we conducted a critical review of clinical studies examining the effects of cannabinoids on subjective and objective measures of sleep. PubMED, Web of Science, and Google Scholar were searched using terms and synonyms related to cannabinoids and sleep. Articles chosen included randomized controlled trials and open label studies. The Cochrane risk of bias tool was used to assess the quality of trials that compared cannabinoids with control interventions. The current literature focuses mostly on the use of tetrahydrocannabinol (THC) and/or cannabidiol (CBD) in the treatment of chronic health conditions such as multiple sclerosis, posttraumatic stress disorder (PTSD), and chronic pain. Sleep is often a secondary, rather than primary outcome in these studies. Many of the reviewed studies suggested that cannabinoids could improve sleep quality, decrease sleep disturbances, and decrease sleep onset latency. While many of the studies did show a positive effect on sleep, there are many limiting factors such as small sample sizes, examining sleep as a secondary outcome in the context of another illness, and relatively few studies using validated subjective or objective measurements. This review also identified several questions that should be addressed in future research. These questions include further elucidation of the dichotomy between the effects of THC and CBD, as well as identifying any long-term adverse effects of medicinal cannabinoid use. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Chronic pain states have resulted in an overreliance on opioid pain relievers, which can carry significant risks when used long term. As such, alternative pain treatments are increasingly desired. Although emerging research suggests that cannabinoids have therapeutic potential regarding pain, results from studies across pain populations have been inconsistent. To provide meta-analytic clarification regarding cannabis's impact on subjective pain, we identified studies that assessed drug-induced pain modulations under cannabinoid and corresponding placebo conditions. A literature search yielded 25 peer-reviewed records that underwent data extraction. Baseline and end-point data were used to compute standardized effect size estimates (Cohen's d) across cannabinoid administrations (k = 39) and placebo administrations (k = 26). Standardized effects were inverse-variance weighted and pooled across studies for meta-analytic comparison. Results revealed that cannabinoid administration produced a medium-to-large effect across included studies, Cohen's d = -0.58, 95% confidence interval (CI) [-0.74, -0.43], while placebo administration produced a small-to-medium effect, Cohen's d = -0.39, 95% CI [-0.52, -0.26]. Meta-regression revealed that cannabinoids, β = -0.43, 95% CI [-0.62, -0.24], p < .05, synthetic cannabinoids, β = -0.39, 95% CI [-0.65, -0.14], p < .05, and sample size, β = 0.01, 95% CI [0.00, 0.01], p < .05, were associated with marked pain reduction. These outcomes suggest that cannabinoid-based pharmacotherapies may serve as effective replacement/adjunctive options regarding pain, however, additional research is warranted. Additionally, given demonstrated neurocognitive side effects associated with some constituent cannabinoids (i.e., THC), subsequent work may consider developing novel therapeutic agents that capitalize on cannabis's analgesic properties without producing adverse effects. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Previous studies have shown that tetrahydrocannabinol (THC), the main psychoactive component of cannabis, can impair cognitive abilities. There is also some evidence that cannabidiol (CBD), the most abundant non-intoxicating constituent of cannabis, can attenuate these effects. The purpose of this study was to investigate the effects of THC, CBD oromucosal spray (with equal parts THC and CBD) on cognition compared with control conditions in human studies.
METHODS:
A systematic literature search was performed on four major bibliographic databases. Studies were included in the present review if they evaluated the cognitive effects of THC, CBD oromucosal spray compared with a control condition.
RESULTS:
Ten studies were identified (7 on patients with multiple sclerosis, 1 on those with Huntington, and 2 on healthy volunteers) with 510 participants in total. There was considerable heterogeneity among the studies in terms of dose and duration of administration. All studies have used an equal or nearly equal dose of THC and CBD.
CONCLUSIONS:
Although the results across studies were somewhat inconsistent, most evidence revealed that there is no significant difference between THC, CBD oromucosal spray and control treatments in terms of cognitive outcomes. However, more trials are needed with longer follow-up periods, and dose considerations, particularly comparing lower and higher doses of the spray.
