Most neurologists treating Parkinson's patients were unaware of contaminants in medical cannabis products | Research

The takeaway

A survey of neurologists treating Parkinson's disease found 65% were unaware of any contaminants in cannabis products, despite PD patients using cannabis at rates 1.5 to 2 times higher than the general population and being potentially more susceptible to environmental toxins.

Neurologists treating Parkinson's disease; medical cannabis program administrators developing safety standards.

65% of neurologists unaware of cannabis product contaminants

What the researchers found

The number of states including PD-related qualifying conditions for medical cannabis increased from 28 to 36 between 2019 and 2023. Among surveyed neurologists, 65% were unaware of any cannabis contaminants. Only 25% knew about pesticide contamination, 15% about toxic elements, and 15% about solvents. PD patients use cannabis at 25-40% compared to 18% in the general population.

Why it matters

Parkinson's patients may be uniquely vulnerable to cannabis contaminants because their neurological condition can be worsened by environmental toxins. If the physicians recommending or discussing cannabis with these patients are unaware of contamination risks, patients cannot make informed decisions.

The numbers in context

PD qualifying conditions: 28 to 36 states (2019-2023). PD-specific states: 14 to 16. Pain qualifying: 17 to 35 states. 45 neurologists surveyed, 44% response. 65% unaware of contaminants. 25% aware of pesticides. 15% aware of toxic elements/solvents. PD cannabis use: 25-40% vs 18% general population.

How the study worked

Two-part study: (1) regulatory analysis of PD-related qualifying conditions across US states from 2019-2023, and (2) online survey of 45 neurologists/movement disorder specialists with 44% response rate.

What this study cannot tell us

Very small survey sample (response from ~20 neurologists). Self-selected respondents. Nine states represented, not nationally comprehensive. Low response rate. Cannot determine whether physician awareness affects patient outcomes.

How to read the evidence

Exploratory survey with very small sample. Highlights a knowledge gap but cannot quantify its clinical impact.

When this study was published

2024 study

The bigger picture

As medical cannabis access expands for neurological conditions, the gap between increasing patient use and physician knowledge about product safety represents a growing risk that extends beyond Parkinson's to all neurology patients.

Questions still open

Are cannabis contaminants actually worsening PD outcomes? Would physician education about cannabis product safety change prescribing behavior?

Common questions

What contaminants are found in cannabis?

Common contaminants include pesticides, heavy metals (lead, cadmium, arsenic), residual solvents from extraction processes, mold, bacteria, and mycotoxins. Testing requirements vary significantly between states.

Why are Parkinson's patients at special risk?

PD patients have compromised neurological function and may be more susceptible to neurotoxic contaminants. Their higher-than-average cannabis use rate increases cumulative exposure. Additionally, PD medication interactions with cannabis are poorly understood.

Read the original research

Cannabis use in Parkinson's disease: Patient access to medical cannabis and physician perspective on product safety.

Neurotoxicology, 103, 198-205

View on PubMed ↗Publisher’s paper ↗

Citation

Griffith, Symone T; Conrow, Kendra D; Go, Michael; McEntee, Mindy L; Daniulaityte, Raminta; Nadesan, Majia H; Swinburne, Mathew R; Shill, Holly A; Leung, Maxwell C K. (2024). Cannabis use in Parkinson's disease: Patient access to medical cannabis and physician perspective on product safety.. Neurotoxicology, 103, 198-205. https://doi.org/10.1016/j.neuro.2024.05.008