# Chronic effects of different THC:CBD ratios on executive function and emotional processing in people with multiple sclerosis

> **NIH NIH R21** · UNIVERSITY OF IOWA · 2022 · $231,750

## Abstract

Project Summary
Approximately 70% of people with multiple sclerosis (PwMS) self-medicate their symptoms with cannabis. Δ-9-
tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most abundant cannabis components. THC
exhibits psychoactive effects, may induce acute psychosis, and impacts executive function. CBD is not
psychoactive like THC and has been shown to be emotionally beneficial (i.e., anxiolytic), anti-inflammatory,
and neuroprotective. Critically, there is a vast diversity in the amounts (i.e., ratios) of THC and CBD
commercially available. Therefore, the ratio of THC: CBD of various strains of cannabis may have a pivotal
impact on executive function and emotional processing (i.e., fear, anxiety) in PwMS. Currently, there is a gap
of understanding surrounding the effects of different ratios of THC:CBD on brain activity, executive function,
and emotional processing in PwMS.
The goal of this application is to conduct a unique observational, cross-sectional study that employs real-world
cannabis products of varying THC:CBD ratios currently available to Iowa residents. We will investigate
differences in executive function, emotional processing, and brain activity in PwMS who have been using
different THC:CBD ratios of cannabis for at least 6 months [High CBD group (CBD >THC); 1:1 group (THC =
CBD); High THC group (THC > CBD); Non-Users group (no cannabis)]. Executive function and emotional
processing will be assessed with valid psychiatric and neuropsychological measures. Positron Emission
Tomography (PET) with [18F]-Fluorodeoxyglucose (FDG) will be used as a measure of brain activity.
Our central hypothesis is that the High THC group will have worse executive function and emotional
processing compared to the High CBD, 1:1, and Non-Users groups, and that the High CBD group will have
better emotional processing compared to the High THC, 1:1, and Non-Users groups. These hypotheses were
formulated based on previous studies and our own preliminary data.
This research on PwMS who are currently using cannabis is well-positioned to critically inform our
understanding of the effects of different THC:CBD ratios and highlight avenues for future longitudinal studies
(R01).

## Key facts

- **NIH application ID:** 10369773
- **Project number:** 1R21NS121141-01A1
- **Recipient organization:** UNIVERSITY OF IOWA
- **Principal Investigator:** Thorsten Rudroff
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $231,750
- **Award type:** 1
- **Project period:** 2021-12-01 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10369773

## Citation

> US National Institutes of Health, RePORTER application 10369773, Chronic effects of different THC:CBD ratios on executive function and emotional processing in people with multiple sclerosis (1R21NS121141-01A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10369773. Licensed CC0.

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