Short-Term Cannabidiol with Δ-9-Tetrahydrocannabinol in Parkinson's Disease: A Randomized Trial

BACKGROUND

Cannabis use is frequent in Parkinson's disease (PD), despite inadequate evidence of benefits and risks.

OBJECTIVE

The aim is to study short-term efficacy and tolerability of relatively high cannabidiol (CBD)/low Δ-9-tetrahydrocannabinol (THC) to provide preliminary data for a longer trial.

METHODS

Persons with PD with ≥20 on motor Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) who had negative cannabis testing took cannabis extract (National Institute of Drug Abuse) oral sesame oil solution for 2 weeks, increasing to final dose of 2.5 mg/kg/day. Primary outcome was change in motor MDS-UPDRS from baseline to final dose.

RESULTS

Participants were randomized to CBD/THC (n = 31) or placebo (n = 30). Mean final dose (CBD/THC group) was 191.8 ± 48.9 mg CBD and 6.4 ± 1.6 mg THC daily. Motor MDS-UPDRS was reduced by 4.57 (95% CI, -8.11 to -1.03; P = 0.013) in CBD/THC group, and 2.77 (-4.92 to -0.61; P = 0.014) in placebo; the difference between groups was non-significant: -1.80 (-5.88 to 2.27; P = 0.379). Several assessments had a strong placebo response. Sleep, cognition, and activities of daily living showed a treatment effect, favoring placebo. Overall adverse events were mild and reported more in CBD/THC than placebo group. On 2.5 mg/kg/day CBD plasma level was 54.0 ± 33.8 ng/mL; THC 1.06 ± 0.91 ng/mL.

CONCLUSIONS

The brief duration and strong placebo response limits interpretation of effects, but there was no benefit, perhaps worsened cognition and sleep, and there was many mild adverse events. Longer duration high quality trials that monitor cannabinoid concentrations are essential and would require improved availability of research cannabinoid products in the United States. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cognitive Safety Data from a Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Phase IIb Study of the Effects of a Cannabidiol and Δ9-Tetrahydrocannabinol Drug on Parkinson's Disease-Related Motor Symptoms

BACKGROUND

Cannabis is increasingly available worldwide but its impact on cognition in Parkinson's disease (PD) is unknown.

OBJECTIVE

Present cognitive safety data from study of an oral high-dose cannabidiol (CBD; 100 mg) and low-dose Δ9-tetrahydocannabinol (THC; 3.3 mg) drug in PD.

METHODS

Randomized, double-blind, parallel-group, placebo-controlled study of a CBD/THC drug administered for 16.3 (SD: 4.2) days, with dosage escalating to twice per day. Neuropsychological tests were administered at baseline and 1-1½ hours after final dose; scores were analyzed with longitudinal regression models (alpha = 0.05). Cognitive adverse events were collected.

RESULTS

When adjusted for age and education, the CBD/THC group (n = 29) performed worse than the placebo group (n = 29) on Animal Verbal Fluency. Adverse cognitive events were reported at least twice as often by the CBD/THC than the placebo group.

CONCLUSION

Data suggest this CBD/THC drug has a small detrimental effect on cognition following acute/short-term use in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Higher risk, higher reward? Self‐reported effects of real‐world cannabis use in Parkinson's disease

Background

Objective

Methods

Results

Conclusions

Are Established Embedded Performance Validity Test Cut-Offs Generalizable to Patients With Multiple Sclerosis?

Objective

Data for the use of embedded performance validity tests (ePVTs) with multiple sclerosis (MS) patients are limited. The purpose of the current study was to determine whether ePVTs previously validated in other neurological samples perform similarly in an MS sample.

Methods

In this retrospective study, the prevalence of below-criterion responding at different cut-off scores was calculated for each ePVT of interest among patients with MS who passed a stand-alone PVT.

Results

Previously established PVT cut-offs generally demonstrated acceptable specificity when applied to our sample. However, the overall cognitive burden of the sample was limited relative to that observed in prior large-scale MS studies.

Conclusion

The current study provides initial data regarding the performance of select ePVTs among an MS sample. Results indicate most previously validated cut-offs avoid excessive false positive errors in a predominantly relapsing remitting MS sample. Further validation among MS patients with more advanced disease is warranted.

The impact of cannabis use on intracarotid amobarbital testing

Chronic cannabis use impacts memory functioning, even while users are not acutely intoxicated. The impact of cannabis use on Wada or intracarotid amobarbital testing (IAT) has not previously been described. We reviewed cannabis consumption in epilepsy patients undergoing IAT during pre-surgical work-up. Of 58 patients reviewed, 16 patients (28%) indicated regular use. During IAT, five regular cannabis users with suspected temporal lobe epilepsy exhibited poor memory while testing their presumptively healthy temporal lobe (i.e., the side opposite that targeted for epilepsy surgery), indicating the potential for an amnestic syndrome post-operatively. It was suspected that the pattern of IAT results for these patients was attributable to the deleterious impact of cannabis use on cognition. Thus, three of the five underwent repeat IAT after a period of enforced abstinence. On repeat IAT, each of the three patients exhibited improved memory performance while testing their healthy temporal lobe, suggesting that the healthy temporal lobe of each mediated sufficient memory ability to allow for epilepsy surgery. These findings raised concerns that frequent cannabis use may alter IAT results, leading to incorrect assessments regarding potential post-operative cognitive deficits, and led to a mandate at our institution that patients must stop cannabis use before IAT.

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28% of patients with suspected temporal lobe epilepsy who underwent intracarotid amobarbital testing over a two year period endorsed regular cannabis use.

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Regular cannabis use may adversely impact intracarotid amobarbital test performance.

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We recommend inquiring about cannabis use in all patients scheduled for IAT and to consider delaying the procedure until they abstain for four weeks from using cannabis products containing THC.

Comparing two models of performance validity assessment in patients with Parkinson's disease who are candidates for deep brain stimulation surgery

Utility of standalone and embedded performance validity tests (PVTs) as well as the decision-making algorithms used to reach clinical conclusions about credible and noncredible performance can be population specific. To better understand PVT utility in Parkinson's disease candidates for deep brain stimulation (DBS) we present on two aims: 1) establishing the frequency data of below-criterion responding for the Medical Symptom Validity Test and three embedded PVTs in a sample of 47 patients with Parkinson's disease, and 2) comparing the efficacy of two models for clinical-decision making regarding noncredible performance. Consistent with expectations from previous studies and desired specificity values, our retrospective analysis indicated that in this sample of presumably well-motived patients, the rate of below-criterion responding was less than 10% for all PVTs administered. Regarding our model comparison, we compared a typical PVT battery that required administration of a standalone measure in all cases against a recently proposed low risk algorithm that attempts to lower testing burden by relying more heavily on embedded PVTs with administration of a standalone measure only in the event of below-criterion performance on an embedded indicator. Results suggest that for patients with Parkinson's disease judged to be at limited risk for noncredible performance, a low risk PVT model may prove both more efficient and less prone to error than a more typical model. Implications for clinical decision-making are discussed, as are limitations of the study and its generalizability.