Dr. Sue Sisley

Background and early career

Sue Sisley trained in internal medicine and psychiatry and built a clinical practice in Arizona focused on complex cases, including veterans with post-traumatic stress disorder. She spent years at the University of Arizona, where she held a faculty position and treated patients through telemedicine programs serving rural and tribal communities ^[1].

Her interest in cannabis was clinical, not ideological. Veterans in her practice repeatedly told her they were using cannabis to manage PTSD symptoms — sleep, nightmares, hyperarousal — and often getting better results than from prescribed SSRIs or benzodiazepines Anecdote. By the early 2010s she had decided the only honest response was to study it under a controlled protocol ^[1][2].

The University of Arizona firing (2014)

In 2014, after years of regulatory wrangling, Sisley's PTSD protocol — sponsored by the Multidisciplinary Association for Psychedelic Studies (MAPS) — finally received approval from the U.S. Public Health Service. Weeks later, the University of Arizona declined to renew her contracts, effectively firing her ^[2][3].

Sisley and MAPS founder Rick Doblin publicly alleged the dismissal was political, pointing to pressure from Arizona state senator Kimberly Yee, who had blocked a related research funding bill ^[3]. The university cited budgetary and procedural reasons. The episode became a national story and a case study in how state politics could derail federally approved cannabis research Strong evidence. Sisley relocated the trial to the Scottsdale Research Institute (SRI), an independent site she ran.

The MAPS PTSD trial (2016–2019)

The triple-blind, placebo-controlled trial enrolled 76 U.S. military veterans with chronic PTSD. Participants smoked one of four conditions over three weeks: high-THC, high-CBD, balanced THC/CBD, or placebo cannabis ^[4].

Results, published in PLOS ONE in 2021, were honest and underwhelming: all groups — including placebo — improved significantly on PTSD symptom scales, with no statistically significant difference between active cannabis and placebo over the short trial period ^[4]. Sisley has been openly self-critical about study limitations: the NIDA-supplied cannabis was low-potency, often moldy, and visibly different from commercial product, which she argues compromised blinding and ceiling potency Strong evidence^[5].

This is a key point often distorted in cannabis advocacy media: the trial did not prove cannabis works for PTSD. It also did not prove it doesn't. It demonstrated that the research material the federal government provided was inadequate to answer the question.

The NIDA monopoly and the DEA lawsuit

For decades, the National Institute on Drug Abuse held a federal monopoly on cannabis grown for U.S. research, via a single contract with the University of Mississippi ^[6]. Researchers — including Sisley — repeatedly complained the material was chemically and visually unlike state-legal cannabis: low cannabinoid content, ground to a powder, and inconsistent in quality ^[5][6].

In 2016 the DEA announced it would accept applications from additional growers. Years passed with no action. In 2019, Sisley and SRI sued the DEA in the Ninth Circuit to compel a response ^[7]. The case, combined with parallel pressure, contributed to the DEA finally beginning to process applications in 2020 and issuing the first new cultivation registrations in 2021 — ending more than 50 years of single-source supply ^[6][7] Strong evidence.

Ongoing work

Sisley continues to run SRI, which has pursued studies on cannabis flower for chronic pain in veterans, psilocybin for various indications, and cannabis quality testing. She has also been a vocal critic of the cannabis industry itself — particularly around contamination, mislabeling of potency, and the use of irradiation to mask microbial issues ^[8] Weak / limited.

She is notable among cannabis researchers for refusing to oversell. In interviews she has repeatedly said the science is still early, that whole-plant cannabis is a complex pharmacological product, and that good policy requires real data rather than activism dressed as evidence ^[2][5].

Legacy and how she's mischaracterized

Cannabis media sometimes describes Sisley as having "proven cannabis treats PTSD." She has not, and she says so plainly ^[5]. The opposite framing — that her trial "showed cannabis doesn't work" — is equally wrong. The trial was underpowered, the drug was substandard, and the follow-up was short ^[4].

Her durable contribution is structural. She is a rare example of a clinician-researcher who used litigation and public testimony to change federal infrastructure for an entire field of study. Whether future cannabis-PTSD trials show benefit or not, they will be conducted with better material because of work she helped force Strong evidence.

Sources

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