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Also known as: Sue Sisley · Susan Sisley

Dr. Sue Sisley

Clinician and researcher who changed federal cannabis research infrastructure through litigation and rigorous trials.

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↯ The honest take

Sisley is often cited as having 'proven cannabis works for PTSD.' She hasn't, and she says so plainly. Her actual contribution is structural: she used a federally approved trial and a DEA lawsuit to force the U.S. government to break a 50-year single-source monopoly on research cannabis. Whether future trials show benefit or harm, they'll use better material because of her work.

Background and early clinical practice

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 [1]. She held a faculty position at the University of Arizona and treated patients through telemedicine programs serving rural and tribal communities [1].

By the early 2010s, Sisley noticed that veterans in her practice were using cannabis to manage PTSD symptoms — sleep disturbances, nightmares, hyperarousal — and many reported better symptom control than from prescribed SSRIs or benzodiazepines Anecdote. She decided the only ethical response was to pursue controlled research rather than continue observing informally [1].

University of Arizona dismissal and institutional conflict (2014)

After years of regulatory negotiation, Sisley's PTSD protocol — sponsored by the Multidisciplinary Association for Psychedelic Studies (MAPS) — received approval from the U.S. Public Health Service in 2014. Within weeks, the University of Arizona declined to renew her contracts [2].

Sisley and MAPS founder Rick Doblin publicly alleged the dismissal was political retaliation, citing pressure from Arizona state senator Kimberly Yee, who had blocked related research funding [2]. The University of Arizona cited budgetary and procedural reasons Strong evidence[2]. The dismissal became a national story and drew attention to how state-level political actors could obstruct federally approved cannabis research [2]. Sisley relocated her trial to the Scottsdale Research Institute (SRI), an independent clinical research site.

The MAPS PTSD trial: design, results and limitations

The trial was a triple-blind, placebo-controlled study that enrolled 76 U.S. military veterans with chronic PTSD. Participants smoked one of four cannabis conditions over three weeks: high-THC, high-CBD, balanced THC/CBD, or placebo [3].

Results published in PLOS ONE in March 2021 showed that all groups — including placebo — improved significantly on standardized PTSD symptom scales, with no statistically significant difference between active cannabis and placebo over the short trial period [3] Strong evidence. This outcome is often misrepresented in cannabis advocacy media as either proof that cannabis works or proof that it doesn't. Neither interpretation is accurate.

Sisley has been publicly critical of the trial's constraints. The cannabis was supplied by the National Institute on Drug Abuse (NIDA) through its monopoly contract with the University of Mississippi. That material was low-potency, often contaminated with mold, and visually and chemically unlike state-legal cannabis — factors Sisley argues compromised both blinding integrity and the ability to test clinically relevant dosing [4] Strong evidence. The trial period of three weeks was also shorter than typical PTSD symptom cycles. Sisley herself has stated plainly that the trial did not prove cannabis treats PTSD, and that further research with better-quality material and longer observation is needed [4].

The NIDA monopoly and the DEA lawsuit

For more than 50 years, the National Institute on Drug Abuse controlled all cannabis available for U.S. federally approved research through a single contract with the University of Mississippi [5]. Researchers — including Sisley — documented that this material was chemically and physically inconsistent with state-legal cannabis: low cannabinoid potency, ground into homogeneous powder, frequently moldy, and unable to answer clinically relevant questions about whole-plant cannabis effects [4][5] Strong evidence.

In 2016, the DEA announced it would accept applications from additional growers to diversify the supply. No applications were processed for years. In 2019, Sisley and the Scottsdale Research Institute sued the DEA in the U.S. Court of Appeals for the Ninth Circuit to compel action on pending applications [6]. The lawsuit, combined with parallel pressure from other researchers and advocates, contributed to the DEA beginning to process applications in 2020. By 2021, the DEA had issued the first new cultivation registrations to additional suppliers, ending the monopoly [5][6] Strong evidence. This structural change affected all downstream federal cannabis research.

Ongoing research and critical voice

Sisley continues to run the Scottsdale Research Institute, which has pursued studies on cannabis flower for chronic pain in veterans, psilocybin-assisted therapy for various indications, and independent cannabis quality testing and contamination analysis No data.

In published commentary and interviews, she has critiqued industry practices around cannabis quality, particularly mislabeling of cannabinoid content, microbial contamination, and the use of irradiation to mask microbial loads while potentially degrading cannabinoid profiles Weak / limited. She has also consistently cautioned against overclaiming efficacy. In public statements, Sisley emphasizes that cannabis is a complex plant pharmacological product, that research is still early, and that sound policy requires rigorous data rather than advocacy framed as evidence [4] Strong evidence.

Legacy: structural change and resisting mythology

Sisley is sometimes described in cannabis media as having "proven cannabis treats PTSD." She has not. The opposite claim — that her trial proved cannabis ineffective — is equally wrong. Both mischaracterizations ignore the actual constraints of the trial design, the substandard research material, and the short observation window [3][4].

Her durable contribution is institutional. Sisley is a rare example of a clinician-researcher who used both rigorous trial design and litigation to change federal research infrastructure. She did not accomplish this through advocacy alone, but by documenting specific failures in the existing system, publishing honest results (including null findings), and using legal pressure to force bureaucratic change. Whether future cannabis-PTSD trials demonstrate benefit or harm, they will be conducted with materially better cannabis and under frameworks she helped establish Strong evidence.

Sources

  1. Reported Ferner M. "Meet The Doctor Fighting To Make Marijuana A Federally Legal Medicine." HuffPost, December 2014.
  2. Reported Wang AB. "University of Arizona fires marijuana researcher." Arizona Republic, June 28, 2014.
  3. Peer-reviewed Bonn-Miller MO, Sisley S, Riggs P, et al. "The short-term impact of 3 smoked cannabis preparations versus placebo on PTSD symptoms: A randomized cross-over clinical trial." PLOS ONE, 2021;16(3):e0246990.
  4. Reported Zhang S. "The Federal Government's Marijuana Is Terrible." The Atlantic, March 20, 2017.
  5. Government U.S. Drug Enforcement Administration. "DEA Continues Its Efforts to Expand Access to Marijuana for Research." Press release, May 14, 2021.
  6. Reported Jaeger K. "DEA Sued Over Marijuana Research Applications." Marijuana Moment, June 2019.

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Oct 31, 2026
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Oct 31, 2026
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