Cannabis-related cognitive impairment: a prospective evaluation of possible influences on patients with cancer during chemotherapy treatment as a pilot study

Impact of Low-Dose Dronabinol Therapy on Cognitive Function in Cancer Patients Receiving Palliative Care: A Case-Series Intervention Study

Background

Cannabis may offer therapeutic benefits to patients with advanced cancer not responding adequately to conventional palliative treatment. However, tolerability is a major concern. Cognitive function is a potential adverse reaction to tetrahydrocannabinol containing regimens. The aim of this study was to test cognitive function in patients being prescribed dronabinol as an adjuvant palliative therapy.

Methods

Adult patients with advanced cancer and severe related pain refractory to conventional palliative treatment were included in this case-series study. Patients were examined at baseline in conjunction with initiation of dronabinol therapy and at a two-week follow-up using three selected Wechsler's adult intelligence scale III neurocognitive tests: Processing Speed Index (PSI), Perceptual Organization Index (POI), and Working Memory Index (WMI). Patients were also assessed using pain visual analog scale, Major Depression Inventory, and Brief Fatigue Inventory.

Results

Eight patients consented to take part in the study. Two patients discontinued dronabinol therapy, one due to a complaint of dizziness and another critical progression of cancer disease, respectively. The remaining six patients were successfully treated with a daily dosage of 12.5 mg dronabinol (p = 0.039). PSI (p = 0.020), POI (p = 0.034.), and WMI (p = 0.039).

Conclusions

Cognitive function improved in this group of patients with advanced cancer in conjunction with low-dose dronabinol therapy. The cause is likely multifactorial including reported relief of cancer-associated symptoms. Further clinical investigation is required.

The association between cannabis use and subjective memory complaints in older adults in the United States

OBJECTIVE

The U.S. population is aging and increasing numbers of older adults are using cannabis. Cognitive decline is common in older age and subjective memory complaints (SMC) have been associated with increased risk for dementia. While residual cognitive effects of cannabis use at younger ages are well understood, the links between cannabis use and cognition in older adults is less clear. The present study represents the first population-level analysis of cannabis use and SMC in older adults in the U.S.

METHOD

We used the National Survey of Drug Use and Health (NSDUH) dataset to evaluate SMC in respondents over age 50 (N = 26,399) according to past-year cannabis use.

RESULTS

Results revealed that 13.2% (95%CI: 11.5%-15.0%) of those who reported cannabis use also reported SMC, compared to 6.4% (95%CI: 6.1%-6.8%) among individuals with no cannabis use. Logistic regression revealed a two-fold increase (OR = 2.21, 95%CI: 1.88-2.60) of reporting SMC in respondents who had used cannabis in the past year, which was attenuated (OR = 1.38, 95%CI: 1.10-1.72) when controlling for additional factors. Other covariates, including physical health conditions, misuse of other substances, and mental illness also significantly contributed to SMC outcomes.

CONCLUSIONS

Cannabis use represents a modifiable lifestyle factor that has potential for both risk and protective properties that may impact the trajectory of cognitive decline in older age. These hypothesis generating results are important for characterizing and contextualizing population-level trends related to cannabis use and SMC in older adults.

Cannabis in Palliative Care: A Systematic Review of Current Evidence

CONTEXT

Palliative care aims to improve the quality of life in patients with incurable illness. Medicinal cannabis (MC) has been used in the palliative care setting to address multiple symptoms in patients.

OBJECTIVES

To evaluate the full scope of available literature investigating the effects and potential harms of MC on symptom management and quality of life in palliative care.

METHODS

PubMed, Embase, The Cochrane Library and clinicaltrials.gov were searched for eligible articles, published between 1960 and September 9, 2021. Quality of the evidence was assessed in accordance with Grading of Recommendations, Assessment, Development and Evaluations. Risk of bias was assessed using the RoB 2 tool for randomised controlled trials and the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) tool for non-randomized trials.

RESULTS

Fifty-two studies (20 randomised; 32 non-randomised) with 4786 participants diagnosed with cancer (n = 4491), dementia (n = 43), AIDS (n = 235), spasticity (n = 16), NORSE syndrome (n = 1) were included. The quality of evidence was 'very low' or 'low' for all studies, and low for only two randomised controlled trials. Positive treatment effects (statistical significance with P < 0.05) were seen for some MC products in pain, nausea and vomiting, appetite, sleep, fatigue, chemosensory perception and paraneoplastic night sweats in patients with cancer, appetite and agitation in patients with dementia and appetite, nausea and vomiting in patients with AIDS. Meta-analysis was unable to be performed due to the wide range of cannabis products used and the heterogeneity of the study outcomes.

CONCLUSION

While positive treatment effects have been reported for some MC products in the palliative care setting, further high quality evidence is needed to support recommendations for its use in clinical practice.

The effect of medical cannabis on cognitive functions: a systematic review

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.

Routes of administration, reasons for use, and approved indications of medical cannabis in oncology: a scoping review

INTRODUCTION

Some patients diagnosed with cancer use medical cannabis to self-manage undesirable symptoms, including nausea and pain. To improve patient safety and oncological care quality, the routes of administration for use of medical cannabis, patients' reasons, and prescribed indications must be better understood.

METHODS

Based on the Joanna Briggs Institute guidelines, a scoping review was conducted to map the current evidence regarding the use of medical cannabis in oncological settings based on the experiences of patients diagnosed with cancer and their healthcare providers. A search strategy was developed with a scientific librarian which included five databases (CINAHL, Web of Science, Medline, Embase, and PsycINFO) and two grey literature sources (Google Scholar and ProQuest). The inclusion criteria were: 1) population: adults aged 18 and over diagnosed with cancer; 2) phenomena of interest: reasons for cannabis use and/or the prescribed indications for medical cannabis; 3) context: oncological setting. French- or English-language primary empirical studies, knowledge syntheses, and grey literature published between 2000 and 2021 were included. Data were extracted by two independent reviewers and subjected to a thematic analysis. A narrative description approach was used to synthesize and present the findings.

RESULTS

We identified 5,283 publications, of which 163 met the eligibility criteria. Two main reasons for medical cannabis use emerged from the thematic analysis: limiting the impacts of cancer and its side effects; and staying connected to others. Our results also indicated that medical cannabis is mostly used for three approved indications: to manage refractory nausea and vomiting, to complement pain management, and to improve appetite and food intake. We highlighted 11 routes of administration for medical cannabis, with oils and oral solutions the most frequently reported.

CONCLUSION

Future studies should consider the multiple routes of administration for medical cannabis, such as inhalation and edibles. Our review highlights that learning opportunities would support the development of healthcare providers' knowledge and skills in assessing the needs and preferences of patients diagnosed with cancer who use medical cannabis.

Clinical Characteristics and Quality of Life in Adults Initiating Medical Marijuana Treatment

INTRODUCTION

Despite the rising availability and use of medical marijuana (MM) in the USA, little is known about the demographics, clinical characteristics, or quality of life of MM patients. This study describes the demographic characteristics and health-related quality of life (HRQoL) of MM patients who are initiating treatment in Pennsylvania.

METHODS

Two-hundred adults naive to MM and referred for any of the 23 state-approved qualifying conditions were recruited at three MM dispensaries in Pennsylvania between September 2020 and March 2021. All participants consented to the study; completed semi-structured interviews that included demographic questionnaires, the Short Form-36 (SF-36), and Generalized Anxiety Disorder-7 (GAD-7); provided height and weight measurements; and allowed access their dispensary medical records.

RESULTS

Participants had a mean age of 48.5 ± 15.6 years, predominantly identified as female (67.5%), and were most commonly referred for chronic pain (63.5%) and/or anxiety (58.5%). Additionally, 46.0% were living with obesity as determined by BMI. Relative to a normative sample, participants reported diminished HRQoL in several domains, most notably in role limitations due to physical health (M = 46.0 ± 42.0), role limitations due to emotional problems (M = 52.5 ± 42.3), energy and fatigue (M = 39.8 ± 20.2), and pain (M = 49.4 ± 26.0).

DISCUSSION/CONCLUSION

Patients initiating MM treatment experienced low HRQoL in multiple domains. Future studies could evaluate the relationship between HRQoL and patients' decisions to pursue MM treatment, as well as changes in HRQoL with MM use over time.

Associations among marijuana use, health-related quality of life, exercise, depression and sleep in cancer survivors

AIMS

To assess associations among cannabis use, health-related quality of life, exercise, depression and sleep among a nationally representative sample of US adults living with cancer.

DESIGN

A cross-sectional correlational study.

METHODS

We used survey data from the 2016-2018 Behavioral Risk Factor Surveillance System. Analyses were considered for sample weights and the complex designs. Logistic regression was performed to assess associations among cannabis use (0, 1-19, vs. 20-30 [frequent] days), health-related quality of life (0-13 vs. ≥14 mentally or physically unhealthy days in the past 30 days; 0-13 vs. ≥14 functionally limited days), exercise, depression, and sleep after accounting for covariates. Reason for cannabis use (medical vs. non-medical) was also assessed.

RESULTS

Frequent users had significantly more physically unhealthy days (adjusted odds ratio [OR]: 1.79, 95% CI: 1.28-2.51, p < .01) and reported ≥ 14 mentally unhealthy days (adjusted OR: 2.43, 95% CI: 1.78-3.32, p < .001) and depression (adjusted OR: 2.65, 95% CI: 1.97-3.57, p < .001) compared with non-users. A positive relationship between frequency of cannabis use and depression existed only among non-medical cannabis users.

CONCLUSION

Cancer survivors using cannabis frequently (20 days+ in the past month) had poorer mental health-related quality of life. The reason for cannabis use as well as frequency of use may be important considerations in predicting depression.

IMPACT

This is the first study that evaluates the associations among cannabis use, the purpose of cannabis use, HRQoL, exercise, depression and sleep in a nationally representative sample of US adults living with cancer. Frequent cannabis users are likely vulnerable to poorer mental health-related quality of life and depression, and non-medical cannabis use in frequent users was associated with depression. Given expanding medical cannabis legalization, these findings warrant further attention so that this information can be used by people living with cancer in decision-making for symptom self-management.

Use of Medical Cannabis to Treat Traumatic Brain Injury

There is not a single pharmacological agent with demonstrated therapeutic efficacy for traumatic brain injury (TBI). With recent legalization efforts and the growing popularity of medical cannabis, patients with TBI will inevitably consider medical cannabis as a treatment option. Pre-clinical TBI research suggests that cannabinoids have neuroprotective and psychotherapeutic properties. In contrast, recreational cannabis use has consistently shown to have detrimental effects. Our review identified a paucity of high-quality studies examining the beneficial and adverse effects of medical cannabis on TBI, with only a single phase III randomized control trial. However, observational studies demonstrate that TBI patients are using medical and recreational cannabis to treat their symptoms, highlighting inconsistencies between public policy, perception of potential efficacy, and the dearth of empirical evidence. We conclude that randomized controlled trials and prospective studies with appropriate control groups are necessary to fully understand the efficacy and potential adverse effects of medical cannabis for TBI.

Medical Cannabis in Oncology: a Valuable Unappreciated Remedy or an Undesirable Risk?

OPINION STATEMENT

The use of the cannabis plant by cancer patients has been rising significantly in the past few years worldwide, primarily driven by public demand. There is an obvious need for more reliable scientific data, pharmacology information, a better understanding of its mode of action, and available clinical evidence supporting its robust use. Physicians must complete a thorough medical assessment, screening for potential drugs, or treatment contraindications before allowing its consumption. In light of the growing popularity of cannabis usage, it is highly essential that, in the near future, the medical community will be able to provide practical recommendations and explicit guidelines, including doses, and that cannabinoid concentrations in the used products are defined regarding its prescription before any medical procedure involving its usage is authorized. Here, we review and describe the favorable outcomes demonstrating the benefits of cannabis as an adjunctive treatment to conventional medicines for chemotherapy-induced nausea, vomiting, and cancer-related pain (primarily refractory chronic or neuropathic pain). Although not yet substantial enough, the treatment of anorexia, insomnia, depression, and anxiety is also seemingly favorable. To date, reports regarding its anti-neoplastic effects or its potent immunosuppressive properties influencing response to immunotherapy are still very conflicting and controversial. Thus, with the current state of evidence, cannabis use is not advisable as initial treatment, as an adjunct or an advanced line of care. In the coming years, we expect that preclinical data and animal models will shift to the clinical arena, and more patients will be recruited for clinical trials, and their reports will advance the field. Thus, physicians should prescribe cannabis only if careful clarification and consideration is provided together with a follow-up response evaluation.

Medical cannabis and cognitive performance in middle to old adults treated for chronic pain

INTRODUCTION AND AIMS

Cannabis exposure is becoming more common in older age but little is known about how it is associated with brain health in this population. This study assesses the relationship between long-term medical cannabis (MC) use and cognitive function in a sample of middle-aged and old chronic pain patients.

DESIGN AND METHODS

A cross-sectional study was conducted among chronic pain patients aged 50+ years who had MC licenses (n = 63) and a comparison group who did not have MC licenses (n = 62). CogState computerised brief battery was used to assess cognitive performance of psychomotor reaction, attention, working memory and new learning. Regression models and Bayesian t-tests examined differences in cognitive performance in the two groups. Furthermore, the associations between MC use patterns (dosage, cannabinoid concentrations, length and frequency of use and hours since last use) with cognition were assessed among MC licensed patients.

RESULTS

Mean age was 63 ± 6 and 60 ± 5 years in the non-exposed and MC patients, respectively. Groups did not significantly differ in terms of cognitive performance measures. Furthermore, none of the MC use patterns were associated with cognitive performance.

DISCUSSION AND CONCLUSIONS

These results suggest that use of whole plant MC does not have a widespread impact on cognition in older chronic pain patients. Considering the increasing use of MC in older populations, this study could be a first step towards a better risk-benefit assessment of MC treatment in this population. Future studies are urgently needed to further clarify the implications of late-life cannabis use for brain health.

The implications of late-life cannabis use on brain health: A mapping review and implications for future research

While medical and recreational cannabis use is becoming more frequent among older adults, the neurocognitive consequences of cannabis use in this age group are unclear. The aim of this literature review was to synthesize and evaluate the current knowledge on the association of cannabis use during older-adulthood with cognitive function and brain aging. We reviewed the literature from old animal models and human studies, focusing on the link between use of cannabis in middle- and old-age and cognition. The report highlights the gap in knowledge on cannabis use in late-life and cognitive health, and discusses the limited findings in the context of substantial changes in attitudes and policies. Furthermore, we outline possible theoretical mechanisms and propose recommendations for future research. The limited evidence on this important topic suggests that use in older ages may not be linked with poorer cognitive performance, thus detrimental effects of early-life cannabis use may not translate to use in older ages. Rather, use in old ages may be associated with improved brain health, in accordance with the known neuroprotective properties of several cannabinoids. Yet, firm conclusions cannot be drawn from the current evidence-base due to lack of research with strong methodological designs.

A Systematic Review of the Neurocognitive Effects of Cannabis Use in Older Adults

Purpose of Review

Older adults currently represent the fastest growing demographic of cannabis users, yet few studies have investigated the effects of cannabis use on cognitive functioning in aging. We conducted a systematic review of the recent literature examining cognitive outcomes associated with cannabis use in older adults, with and without neurocognitive disorders, to clarify the potential neuroprotective benefits and risks of cognitive decline in this population.

Recent Findings

We identified 26 studies examining cognitive outcomes associated with medical and recreational use of cannabis in healthy aging, dementia, Parkinson's disease, multiple sclerosis, HIV, and pain populations. Although variability in the cannabis products used, outcomes assessed, and study quality limits the conclusions that can be made, modest reductions in cognitive performance were generally detected with higher doses and heavier lifetime use.

Summary

This review highlights the need for additional high-quality research using standardized, validated assessments of cannabis exposure and cognitive outcomes. Reliable measures and longitudinal data are necessary to better characterize the effects of cannabis use on cognitive aging, as well as differential effects of recreational and medical cannabis.

Opportunities for cannabis in supportive care in cancer

Cannabis has the potential to modulate some of the most common and debilitating symptoms of cancer and its treatments, including nausea and vomiting, loss of appetite, and pain. However, the dearth of scientific evidence for the effectiveness of cannabis in treating these symptoms in patients with cancer poses a challenge to clinicians in discussing this option with their patients. A review was performed using keywords related to cannabis and important symptoms of cancer and its treatments. Literature was qualitatively reviewed from preclinical models to clinical trials in the fields of cancer, human immunodeficiency virus (HIV), multiple sclerosis, inflammatory bowel disease, post-traumatic stress disorder (PTSD), and others, to prudently inform the use of cannabis in supportive and palliative care in cancer. There is a reasonable amount of evidence to consider cannabis for nausea and vomiting, loss of appetite, and pain as a supplement to first-line treatments. There is promising evidence to treat chemotherapy-induced peripheral neuropathy, gastrointestinal distress, and sleep disorders, but the literature is thus far too limited to recommend cannabis for these symptoms. Scant, yet more controversial, evidence exists in regard to cannabis for cancer- and treatment-related cognitive impairment, anxiety, depression, and fatigue. Adverse effects of cannabis are documented but tend to be mild. Cannabis has multifaceted potential bioactive benefits that appear to outweigh its risks in many situations. Further research is required to elucidate its mechanisms of action and efficacy and to optimize cannabis preparations and doses for specific populations affected by cancer.