Most epilepsy patients using marijuana in Oregon did so for seizures and believed it helped, but almost none knew their dose

Among 39 epilepsy patients surveyed in Oregon, 87% used cannabis specifically for seizures, 82% agreed it improved seizure control, but only 2 of 39 could state their actual dose in milligrams, and most used multiple cannabis forms.

Kerr, Alysse et al.·Epilepsy & behavior : E&B·2019·Preliminary EvidenceCross-Sectional
RTHC-02101Cross SectionalPreliminary Evidence2019RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

87.2% used cannabis to treat epilepsy. 82% agreed it improved seizure control. Most common strains: high-CBD (30.8%) or multiple types (30.8%). Methods: smoking (66.7%), edibles (48.7%), concentrates (43.6%). Only 2/39 knew their dose. Fewer women used primarily THC (10% vs 47% of men).

Key Numbers

39 cannabis-using epilepsy patients. 87.2% used for seizures. 82% agreed it helped. Only 2/39 knew their dose. High-CBD: 30.8%. Multiple types: 30.8%. Smoking: 66.7%. Edibles: 48.7%. Women vs men using THC-dominant: 10% vs 47%.

How They Did This

Nine-item survey of patients seen in an epilepsy clinic over 9 months at a tertiary care center in Oregon, where recreational cannabis was legalized in 2015.

Why This Research Matters

Even as pharmaceutical CBD (Epidiolex) gained FDA approval, epilepsy patients were already self-treating with dispensary products. The near-universal inability to state doses highlights a fundamental safety gap between pharmaceutical and dispensary cannabis.

The Bigger Picture

The fact that only 5% of epilepsy patients using cannabis could specify their dose is a stark illustration of the gap between medical claims about cannabis and medical-grade practice. This is the fundamental tension of cannabis as medicine: patients believe it works, but they cannot dose it like a medicine.

What This Study Doesn't Tell Us

Small convenience sample from one clinic. Self-reported seizure improvement without objective seizure diary data. Survey design limits depth of response. Oregon-specific population.

Questions This Raises

  • ?How does patient-perceived seizure improvement compare to objectively measured seizure frequency?
  • ?Would standardized dosing guidance improve outcomes?
  • ?Should epilepsy clinics provide cannabis counseling alongside seizure management?

Trust & Context

Key Stat:
87% used cannabis for seizures; only 2 of 39 knew their dose in milligrams
Evidence Grade:
Preliminary: small single-clinic survey with self-reported outcomes.
Study Age:
Published in 2019.
Original Title:
Marijuana use among patients with epilepsy at a tertiary care center.
Published In:
Epilepsy & behavior : E&B, 97, 144-148 (2019)
Database ID:
RTHC-02101

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

Do epilepsy patients find cannabis helpful?

In this survey, 82% of cannabis-using epilepsy patients agreed it improved seizure control. However, this is self-reported without objective seizure counting, and almost none could specify their dose, making it impossible to evaluate dosing relationships.

What cannabis products do epilepsy patients use?

Most commonly high-CBD strains or multiple types. Two-thirds smoked cannabis, about half used edibles, and 44% used concentrates. There was a notable sex difference: far fewer women used THC-dominant products compared to men.

Read More on RethinkTHC

Cite This Study

RTHC-02101·https://rethinkthc.com/research/RTHC-02101

APA

Kerr, Alysse; Walston, Victoria; Wong, Victoria S S; Kellogg, Marissa; Ernst, Lia. (2019). Marijuana use among patients with epilepsy at a tertiary care center.. Epilepsy & behavior : E&B, 97, 144-148. https://doi.org/10.1016/j.yebeh.2019.05.037

MLA

Kerr, Alysse, et al. "Marijuana use among patients with epilepsy at a tertiary care center.." Epilepsy & behavior : E&B, 2019. https://doi.org/10.1016/j.yebeh.2019.05.037

RethinkTHC

RethinkTHC Research Database. "Marijuana use among patients with epilepsy at a tertiary car..." RTHC-02101. Retrieved from https://rethinkthc.com/research/kerr-2019-marijuana-use-among-patients

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.