Carlos Zamarripa
Johns Hopkins University, MD·Pharmacology
Laws about drugs are changing much faster than the science that should guide them. Cannabis edibles are sold in retail stores, psilocybin (the active compound in "magic mushrooms") is being decriminalized and allowed for supervised therapeutic use in some jurisdictions, and kratom, a leaf product from a Southeast Asian tree, is sold legally across most of the United States.
- Fields
Pharmacology
Medicine & Clinical Research
Public Health & Epidemiology
- Topics
psilocybin
psilocin
cannabis edibles
- Grants
- 3 known grants, through May 2031
What they work on
- Characterize how psilocybin doses of 1, 5, 15, and 25 mg affect simulated driving and computerized cognitive and psychomotor performance, and test whether impairment at higher doses matches alcohol at 0.08% blood alcohol concentration.
- Measure psilocybin's subjective intoxication and abuse liability using drug-liking ratings, confidence in driving ability, field sobriety tests, and behavioral economic purchase tasks that index how much participants would pay for the drug.
- Relate blood concentrations of psilocybin and its active metabolite psilocin to measured behavioral impairment, and test whether people's perceived intoxication tracks their actual driving deficits.
- Test whether increasing cannabidiol relative to THC in brownies (ratios 1:0 through 1:30 at a fixed 10 mg THC dose) increases plasma THC and metabolite concentrations and the resulting subjective, cognitive, and driving effects.
- Determine dose-dependent effects of 0, 1, 2, and 4 standard THC units given alone or with CBD at a realistic 1:30 ratio, to see whether edible ratios matter alongside standardized THC dosing.
- Establish the safety and tolerability of a standardized whole-leaf kratom product from 0.5 g to 10 g in 88 healthy adults using a triple-blind single ascending dose design with pre-set go/no-go escalation criteria.
- Compare the abuse potential and pharmacokinetics of low and high kratom doses against placebo, oxycodone 10 mg, and methylphenidate 20 mg in 40 healthy adults across randomized outpatient sessions.
More about the research
For all three, basic questions remain unanswered: how much of the drug actually gets into the blood from a given product, how impaired does a person become, how well does someone judge their own impairment, and how likely is the drug to be misused. Work here addresses those questions with controlled human laboratory studies in healthy adults, measuring drug and metabolite concentrations in blood (pharmacokinetics) alongside objective and subjective effects (pharmacodynamics), including performance on a driving simulator and standardized tests of abuse potential.
Why it matters
Policies on driving, product labeling, and dosing for psilocybin, cannabis edibles, and kratom are being written with little controlled human data. These studies could give regulators and clinicians concrete numbers: how psilocybin impairment at specific doses compares with the 0.08% alcohol limit, whether CBD-to-THC ratios in edibles need to be labeled alongside THC content to prevent unexpectedly strong effects, and what kratom doses are well tolerated and how its abuse potential compares with an opioid and a stimulant. Consumers, patients receiving psilocybin therapy, and public safety agencies would be the direct beneficiaries.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
The Impact of Cannabidiol on the Pharmacokinetics and Pharmacodynamics of Oral Delta-9-Tetrahydrocannabinol
NIH · Jul 2026 – May 2031
The Impact of Dose on the Impairing, Intoxicating, and Abuse-Related Effects of Psilocybin
NIH · Aug 2026 – May 2030
Evaluating kratom using a human drug development methodology
NIH · Sep 2025 – May 2030
Closest labs
Chad Brummett
University of Michigan, MI·Medicine & Clinical Research
Test whether cannabidiol (CBD, as the FDA-approved drug Epidiolex) taken around surgery reduces opioid use in the 4 weeks after total knee arthroplasty, in a double-blind, placebo-controlled trial of 380 patients.
Elise Weerts
Johns Hopkins University, MD·Pharmacology
Test whether vaporized cannabis extract produces effects that rats trained on injected THC recognize as similar, and whether a CB1 receptor blocker cancels them, using drug discrimination procedures.
Renee Martin-Willett
University of Colorado Boulder, CO·Psychology·Early-career
Test whether cannabidiol (CBD), a non-intoxicating cannabis compound, improves sleep in adults who report heavy drinking, using a randomized placebo-controlled trial.
The school
Johns Hopkins University: 100 labs on PI Pages, $4.1B a year on research, 622 research doctorates a year.
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