A preliminary study of the effects of cannabidiol (CBD) on brain structure in patients with epilepsy

Brain temperature and free water increases after mild COVID-19 infection

The pathophysiology underlying the post-acute sequelae of COVID-19 remains understudied and poorly understood, particularly in healthy adults with a history of mild infection. Chronic neuroinflammation may underlie these enduring symptoms, but studying neuroinflammatory phenomena in vivo is challenging, especially without a comparable pre-COVID-19 dataset. In this study, we present a unique dataset of 10 otherwise healthy individuals scanned before and after experiencing mild COVID-19. Two emerging MR-based methods were used to map pre- to post-COVID-19 brain temperature and free water changes. Post-COVID-19 brain temperature and free water increases, which are indirect biomarkers of neuroinflammation, were found in structures functionally associated with olfactory, cognitive, and memory processing. The largest pre- to post-COVID brain temperature increase was observed in the left olfactory tubercle (p = 0.007, 95% CI [0.48, 3.01]), with a mean increase of 1.75 °C. Notably, the olfactory tubercle is also the region of the primary olfactory cortex where participants with chronic olfactory dysfunction showed the most pronounced increases as compared to those without lingering olfactory dysfunction (adjusted pFDR = 0.0189, 95% CI [1.42, 5.27]). These preliminary insights suggest a potential link between neuroinflammation and chronic cognitive and olfactory dysfunction following mild COVID-19, although further investigations are needed to improve our understanding of what underlies these phenomena.

Regional brain atrophy and aberrant cortical folding relate to anxiety and depression in patients with traumatic brain injury and psychogenic nonepileptic seizures

OBJECTIVE

Psychogenic nonepileptic seizures (PNES) are characterized by multifocal and global abnormalities in brain function and connectivity. Only a few studies have examined neuroanatomic correlates of PNES. Traumatic brain injury (TBI) is reported in 83% of patients with PNES and may be a key component of PNES pathophysiology. In this study, we included patients with TBI preceding the onset of PNES (TBI-PNES) and TBI without PNES (TBI-only) to identify neuromorphometric abnormalities associated with PNES.

METHODS

Adults diagnosed with TBI-PNES (n = 62) or TBI-only (n = 59) completed psychological questionnaires and underwent 3-T magnetic resonance imaging. Imaging data were analyzed by voxel- and surface-based morphometry. Voxelwise general linear models computed group differences in gray matter volume, cortical thickness, sulcal depth, fractal dimension (FDf), and gyrification. Statistical models were assessed with permutation-based testing at 5000 iterations with the Threshold-Free Cluster Enhancement toolbox. Logarithmically scaled p-values corrected for multiple comparisons using familywise error were considered significant at p < .05. Post hoc analyses determined the association between structural and psychological measures (p < .05).

RESULTS

TBI-PNES participants demonstrated atrophy of the left inferior frontal gyrus and the right cerebellum VIII. Relative to TBI-only, TBI-PNES participants had decreased FDf in the right superior parietal gyrus and decreased sulcal depth in the left insular cortex. Significant clusters were positively correlated with global assessment of functioning scores, and demonstrated varying negative associations with measures of anxiety, depression, somatization, and global severity of symptoms.

SIGNIFICANCE

The diagnosis of PNES was associated with brain atrophy and reduced cortical folding in regions implicated in emotion processing, regulation, and response inhibition. Cortical folds primarily develop during the third trimester of pregnancy and remain relatively constant throughout the remainder of one's life. Thus, the observed aberrations in FDf and sulcal depth could originate early in development. The convergence of environmental, developmental, and neurobiological factors may coalesce to reflect the neuropathophysiological substrate of PNES.

Cannabidiol (CBD) and cognition in epilepsy

Anecdotal reports of the benefits of cannabis and its components in the treatment of epilepsy have been reported for millennia. However, only recently randomized controlled trial data in support of cannabidiol (CBD) became available resulting in its FDA approval for the treatment of seizures and epilepsy. One of the most common and debilitating comorbidities of epilepsy is cognitive impairment. This impairment has a multifactorial etiology including network dysfunction due to seizures, negative cognitive side effects from anti-seizure medications (ASMs), and mood disturbances. Knowing the effects of a particular ASM (either positive or negative) is vital for providers to counsel patients on expected side effects, and may result in choosing a particular regimen over the other if the patient already suffers from significant cognitive deficits. Unlike most other ASMs and other well-studied cannabinoids such as Δ9-tetrahydrocannabinol, CBD has been shown to have additional mechanisms of action (MOA) that result in neuroprotective, anti-inflammatory, anti-oxidant, and neurogenesis effects. These additional MOAs suggest that the use of CBD could lead to other actions including positive effects on cognition that may be independent of seizure control. This targeted review discusses the currently available data on CBD's effects on cognition in epilepsy. First, we review the proposed mechanisms by which CBD could exert effects on cognition. Then, we present the pre-clinical/animal data investigating cognitive effects of CBD in seizure/epilepsy models. Finally, we discuss the available human data, including the studies in people with epilepsy that included cognitive evaluations pre- and on-CBD, and studies investigating if CBD has any effects on brain structure or function in areas pertinent to memory and cognitive functions.

Long-term safety and efficacy of highly purified cannabidiol for treatment refractory epilepsy

OBJECTIVE

To evaluate the safety, efficacy, and tolerability of highly purified cannabidiol (CBD) for the treatment of seizures in children and adults with treatment-resistant epilepsy (TRE) in an open-label, expanded access program (EAP).

METHODS

One hundred sixty-nine participants (89 children and 80 adults) with TRE received plant-derived highly purified CBD (Epidiolex® in the U.S.; 100 mg/mL oral solution) with a starting dose of 5 mg/kg/day divided twice per day and titrated to a maximum dose of 50 mg/kg/day over the study period to seizure control and tolerability and followed for up to 2 years. Seizure frequency (calendars) and severity (Chalfont Seizure Severity Score; CSSS) were collected at every study visit. Adverse Events were reported at/between study visits as required, and participants also completed Adverse Events Profile (AEP) which generates a numerical representation of AEs. Response to CBD was defined as ≥50% reduction in seizure frequency. Given non-normal distribution of seizure frequency, a log transformation was applied after which the generalized least squares regression model for longitudinal data was used.

RESULTS

Evidence from the adjusted model revealed a significant mean reduction in seizure frequency compared to baseline in children and adults at all time points (1 month and 1 and 2 years). Percentage of children achieving ≥50% seizure frequency reduction was 44% at month 1, and 41% at year 1, and 61% reduction at year 2, while adult responder rates were 34% at month 1, 53% at year 1, and 71% at year 2 (all P < 0.0001). CSSS showed a sustained reduction from baseline to all 3 time points. Children displayed 52% seizure reduction at month 1, a 51% reduction at year 1, and 75% reduction at year 2. Seizure reductions in adults were 60%, 81%, and 85%, respectively (all P < 0.0001). While there were no significant differences between seizure frequency reduction between children and adults at all time points, there was a significant difference in seizure severity reduction at year 1, with adults reporting greater improvement in seizure severity (P < 0.001). The most commonly reported adverse events in the study period were diarrhea, sedation, and decreased appetite. AEP revealed significant improvement from baseline at multiple time points in adults and children, and the mean AEP scores were always lower compared to baseline over the duration of the study.

SIGNIFICANCE

Our study provides further evidence of sustained seizure frequency and severity reduction over two years of treatment with highly purified CBD in TRE. In addition, CBD was generally well tolerated with minority of participants experiencing adverse events resulting in stopping CBD.

White matter integrity after cannabidiol administration for treatment resistant epilepsy

OBJECTIVE

The effects of individual cannabinoids on white matter integrity are unclear. Human studies have shown white matter maturation alterations in regular recreational cannabis users with the magnitude of these effects dependent on the age of exposure. However, studies have yet to determine which phytocannabinoids are most responsible for these changes. In the current study, we analyzed the effects of pharmaceutical grade cannabidiol oral solution (CBD; Epidiolex® in the U.S.; Epidyolex® in the EU; 100 mg/mL oral solution) on white matter integrity using diffusion MRI in patients with treatment resistant epilepsy (TRE).

METHODS

15 patients with TRE underwent 3 T diffusion MRI prior to receiving CBD and then again approximately 12 weeks later while on a stable dose of CBD for at least two weeks. DTI analyzes were conducted using DSI Studio and tract-based spatial statistics (TBSS).

RESULTS

DTI analysis using DSI Studio showed significant increases in fractional anisotropy (FA) in the right medial lemniscus (p = 0.03), right superior cerebellar peduncle (p = 0.03) and the pontine crossing tract (p = 0.04); decreased mean diffusivity (MD) in the left uncinate fasciculus (p = 0.02) and the middle cerebellar peduncle (p = 0.04); decreased axial diffusivity (AD) in the left superior cerebellar peduncle (p = 0.05), right anterior limb of the internal capsule (p = 0.03), and right posterior limb of the internal capsule (p = 0.02); and decreased radial diffusivity (RD) in the middle cerebellar peduncle (p = 0.03) and left uncinate fasiculus (p = 0.01). The follow-up ANCOVA also yielded significant results when controlling for covariates of CBD dosage, age, sex, change in seizure frequency, and scanner type: FA increased in the pontine crossing tract (p = 0.03); RD decreased in the middle cerebellar peduncle (p = 0.04) and left uncinate fasciculus (p = 0.04). Subsequent TBSS analysis controlling for the same variables yielded no significant white matter differences between groups.

CONCLUSION

These findings indicate relatively minor short-term effects of highly-purified plant-derived CBD on white matter structural integrity in patients with TRE.

Highly Purified Cannabidiol for Epilepsy Treatment: A Systematic Review of Epileptic Conditions Beyond Dravet Syndrome and Lennox-Gastaut Syndrome

BACKGROUND

Cannabidiol (CBD), which is one major constituent of the Cannabis sativa plant, has anti-seizure properties and does not produce euphoric or intrusive side effects. A plant-derived, highly purified CBD formulation with a known and constant composition has been approved by the US Food and Drug Administration for the treatment of seizures associated with Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. In the European Union, the drug has been authorized by the European Medicines Agency for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome, in conjunction with clobazam, and is under regulatory review for the treatment of seizures in patients with tuberous sclerosis complex.

OBJECTIVES

This systematic review aimed to summarize the currently available body of knowledge about the use of this US Food and Drug Administration/European Medicines Agency-approved oral formulation of pharmaceutical-grade CBD in patients with epileptic conditions, especially developmental and epileptic encephalopathies other than Dravet syndrome and Lennox-Gastaut syndrome.

METHODS

The relevant studies were identified through MEDLINE and the US National Institutes of Health Clinical Trials Registry in October 2020. There were no date limitations or language restrictions. The following types of studies were included: clinical trials, cohorts, case-control, cross-sectional, clinical series, and case reports. Participants had to meet the following criteria: any sex, any ethnicity, any age, diagnosis of epilepsy, receiving plant-derived, highly purified (> 98% w/w) CBD in a sesame oil-based oral solution for the treatment of seizures. Data extracted from selected records included efficacy, tolerability, and safety outcomes.

RESULTS

Five hundred and seventy records were identified by database and trial register searching. Fifty-seven studies were retrieved for detailed assessment, of which 42 were eventually included for the review. The participants of the studies included patients of both pediatric and adult age. Across the trials, purified CBD was administered at dosages up to 50 mg/kg/day. In a randomized double-blind controlled trial in patients with tuberous sclerosis complex, CBD was associated with a significantly greater percent reduction in seizure frequency than placebo over the treatment period. Open-label studies suggested the effectiveness of CBD in the treatment of children and adults presenting with other epilepsy syndromes than those addressed by regulatory trials, including CDKL5 deficiency disorder and Aicardi, Dup15q, and Doose syndromes, SYNGAP1 encephalopathy, and epilepsy with myoclonic absences. The most common adverse events observed during treatment with CBD included somnolence, decreased appetite, diarrhea, and increased serum aminotransferases.

CONCLUSIONS

The currently available data suggest that response to treatment with a highly purified, plant-derived CBD oil-based solution can be seen in patients across a broad range of epilepsy disorders and etiologies. The existing evidence can provide preliminary support for additional research.

Cognitive function and adaptive skills after a one-year trial of cannabidiol (CBD) in a pediatric sample with treatment-resistant epilepsy

OBJECTIVE

Cannabidiol (CBD) is a nonpsychoactive derivative of cannabis. Studies indicate that it is safe and effective in treating certain types of epilepsy. The present study examined the presence of adverse or beneficial cognitive or functional adaptive effects associated with CBD in the treatment of children, adolescents, and teenagers with treatment-resistant epilepsy (TRE) as part of an ongoing prospective, open-label safety study.

METHODS

Participants (N = 38) between the age of 3 and 19 years with TRE were enrolled in an open-label study of a pharmaceutical formulation of CBD (Epidiolex®; GW Research Ltd.) as an add-on treatment. In addition to baseline physical, neurological, and laboratory testing, cognitive assessment was completed prior to initiating CBD and after one year, both using the NIH Toolbox Cognition Battery (NIHTB-CB). Many participants were unable to complete the NIHTB-CB because of the magnitude of their cognitive impairment (n = 24), and in these cases, the participant's caregiver was asked to complete the Adaptive Behavior Assessment System - Second Edition (ABAS-II) as a measure of functional adaptive skills.

RESULTS

There were no statistically significant changes in cognitive function, as measured by the NIHTB-CB, in those participants who were able to complete such testing, but there was a nonsignificant trend toward improvement in some cognitive domains. For participants who were unable to complete formal standardized cognitive testing because of the magnitude of their cognitive impairment, their functional adaptive skills, as measured by the ABAS-II, were unchanged after a one-year trial of CBD.

SIGNIFICANCE

Our findings suggest that CBD, as an add-on drug for TRE in a pediatric sample, does not appear to cause adverse effects (AEs) involving cognition or adaptive function over one year of treatment.