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Physicians and Researchers Shaping Geriatric Cannabis Care

Dr. Ethan Russo, Dr. Donald Abrams, Dr. Dustin Sulak, Dr. Sue Sisley, Dr. Mary Clifton, and the named clinicians whose work informs this site.

The field of cannabis medicine for older adults is small but growing, anchored by clinicians and researchers whose work directly shapes how seniors access, use, and benefit from cannabis. These are the people whose names appear most often in the peer-reviewed literature and clinical practice guidelines that inform this site.

Eloise Theisen, MSN, RN, AGPCNP-BC

Arguably the single most important figure in geriatric cannabis care. A board-certified Adult-Geriatric Nurse Practitioner now at Stanford Medicine's palliative care department, Theisen has treated over 7,000 patients using cannabis, with an average patient age of 76 years. She co-founded Radicle Health and serves as Chief Nursing Officer of Leaf411, the first free national cannabis-trained nurse hotline.

Theisen was among the first clinicians to develop dosing protocols specifically for elderly patients. Her approach reflects a pragmatic reality she witnessed firsthand: "I found that our patients were going to use it whether their providers approved of it or not. Many of our patients were older, and they had risks that needed to be evaluated and addressed before they started using cannabis."

Dr. Dustin Sulak, DO

Founder of Healer.com and Integr8 Health in Maine, Dr. Sulak has followed more than 18,000 patients and authored Handbook of Cannabis for Clinicians (Norton) — considered the first foundational clinical text in the field.

His most influential contribution is the sensitization protocol, a six-day cannabis tolerance reset that helps patients reduce consumption by up to 60% while achieving better therapeutic results. A strong advocate of microdosing for older adults, he estimates that 90% of people find their effective microdose between 1 and 5 mg of THC.

Dr. Sulak has also developed Healer Respite, a full-spectrum hemp gummy specifically designed for dementia-related agitation and sundowning — addressing one of the most distressing symptoms caregivers and families face.

Dr. Donald Abrams

Professor Emeritus of Medicine at UCSF and co-author of the 2024 ASCO Guideline on Cannabis and Cannabinoids in Adults with Cancer. Dr. Abrams has conducted pioneering clinical trials including studies on vaporized cannabis for HIV-related neuropathy and sickle cell disease.

His research found that combining cannabis and morphine improved analgesic effects, possibly through delayed gastrointestinal motility producing a sustained-release effect. He has noted that cannabis is the only antiemetic that also stimulates appetite — a unique advantage for patients experiencing both nausea and cachexia.

Dr. Ethan Russo

A board-certified neurologist and founder of CReDO Science. Dr. Russo served as Medical Director for GW Pharmaceuticals during the development of Epidiolex (FDA-approved CBD for seizures) and Sativex (a nabiximols oromucosal spray).

He is best known for two foundational concepts. The entourage effect — the idea that cannabis compounds work together more effectively than in isolation. And Clinical Endocannabinoid Deficiency — the theory that conditions like migraines, fibromyalgia, and irritable bowel syndrome may result from insufficient endocannabinoid tone. This theory has particular relevance for seniors, since research shows endocannabinoid signaling diminishes with age.

Dr. Rachel Knox

Co-founder of American Cannabinoid Clinics in Portland, Oregon. Dr. Knox has championed "endocannabinology" as a medical discipline — a framework that treats the endocannabinoid system as a legitimate focus of clinical medicine rather than a fringe topic. She chaired the Oregon Cannabis Commission, helping shape state policy around medical cannabis access and regulation.

Dr. Sue Sisley

Director of the Scottsdale Research Institute. Dr. Sisley conducted the first DEA-approved randomized controlled trial of smoked cannabis for veteran PTSD — a landmark 76-veteran study published in PLOS ONE (2021). While the trial found all groups, including placebo, showed significant improvement, Dr. Sisley attributed this partly to the poor quality of NIDA-supplied cannabis, which she described as "homogeneous green dust" far below the potency patients access commercially.

In 2021, she secured a breakthrough DEA Schedule I manufacturing license to grow research-grade cannabis, ending the federal government's monopoly on cannabis for research purposes.

Dr. Benjamin Han

Associate Professor at UC San Diego's Division of Geriatrics and the leading epidemiologist tracking cannabis trends among older adults. His definitive JAMA Internal Medicine studies have documented the surge in senior adoption — including the finding that past-month cannabis use among adults 65 and older reached 7% in 2023, up from just 0.4% in 2006.

Dr. Han's earlier research with Dr. Joseph Palamar at NYU found that 92.9% of adults aged 50 to 64 who used cannabis in 2015-2016 had first tried it before age 21 — revealing that most current senior users are returning to cannabis, not discovering it for the first time.