Why Most ‘Game Changing’ Cannabis Studies Can’t Be Trusted

Reason why most cannabis studies aren't reliable

While it’s tempting to jump to conclusions about cannabis’ usefulness based on a single study — it doesn’t give us a clear understanding of the plant’s potential risks and benefits. Image Credit: By HQuality

Trying to keep pace with the suddenly fast-paced world of cannabis research often feels like chasing a rollercoaster. One moment, you’re reading about how a single dose of CBD could reduce psychosis symptoms. The next, you’re looking at a study that says there’s little proof cannabinoids can treat mental disorders. What exactly are you supposed to believe?

Some legalization proponents have a tendency to inflate the importance of every pro-cannabis study that manages to get published in an academic journal. If research shows a (relatively) massive dose of CBD leads to reduced aggression in lab mice, this might be touted as proof the non-intoxicating cannabinoid is the answer to road rage or toxic masculinity in humans — regardless of how big a logical leap that might be.

The same holds true (perhaps even truer) for opponents of legalization. A study that shows teens who use synthetic cannabis have a higher risk of neuropsychiatric side effects can be blown out of proportion by those who believe the plant is dangerous and should be illegal, regardless of the fact that “real” cannabis has little in common with K2, Spice, or other synthetic cannabinoids.

Interestingly, both sides of this debate over cannabis research often ignore the verdicts of the researchers themselves, who usually qualify their findings with “more studies are needed” or similar disclaimers. Any scientist worth their lab coat knows that a single positive (or negative) result doesn’t mean much until it’s replicated time and again by other researchers who aren’t personally invested in seeing a certain outcome.

As a result, while it’s tempting to jump to conclusions about cannabis’ usefulness/uselessness for a given condition based on a single study — especially when that study is covered extensively in the media — you’re more likely to end up with mental whiplash rather than a clear understanding of the plant’s potential risks and benefits.

Case Study: The New Research Into Cannabis and Dementia

To illustrate, it’s helpful to look at one of the most interesting cannabis studies currently in progress.

Recently, researchers at the University of Notre Dame Australia’s Institute for Health Research announced that they were finally ready to begin a study into cannabis and dementia that has been in the works for two years. Their research will investigate how cannabis could improve the symptoms and quality of life for individuals with conditions like Alzheimer’s.

Although the actual clinical trials aren’t slated to start until 2020, they’ve already the subject of immense media buzz, inspiring headlines like “Medicinal cannabis could hold key to treating dementia sufferers” and “Cannabis could be used in dementia treatment after world-first trial in Perth.”

There’s little wonder why the study has attracted so much attention. An estimated 50 million people around the world are suffering from dementia, according to the World Health Organization (WHO). And while studies show the prevalence of dementia has dropped in recent years, the number of people who actually have the condition continues to increase.

If you’re wondering how that’s possible, it’s because the number of aging adults is on the rise. As a result, there are more overall cases of dementia despite the fact that a lower percentage of people are being diagnosed with it. The Centers for Disease Control and Prevention (CDC) has estimated that 3.3 percent of Americans could have dementia by 2060.

Could Cannabis Replace Conventional Dementia Medications? It’s a Stretch (for Now)

This is especially worrisome because there’s no cure for dementia, through drugs like cholinesterase inhibitors can be useful in treating cognitive symptoms for people with certain types of the condition. Unfortunately, these medications have been linked with a wide range of side effects. According to the U.K.’s Alzheimer’s Society, these include:

  • Hallucinations
  • Aggression or agitation
  • Muscle pain
  • Loss of appetite
  • Sleep problems
  • Nausea and/or diarrhea
  • Headaches

Dementia is already a qualifying condition for medical cannabis in a number of U.S. states. Given the severe impact on quality of life for both patients and their families, it’s understandable that many people would have high hopes for this study (or conversely, look forward to seeing it debunk the notion of cannabis as a dementia treatment so that more effective options could be explored).

However, no matter which side you’re on, you might want to temper your expectations a bit.

Conflicting Evidence Is Common in Cannabis Research

Cannabis research has been hamstrung for the better part of a century, both in the United States and around the world. Today, governments are beginning to relax restrictions on studying the plant, but there’s still a lot of ground to make up — and a lot of thorny questions to be answered (or re-answered).

Since researchers have traditionally found it hard to get permission, funding, and/or study material in the form of cannabis itself, many previous studies have faced significant limitations, such as:

  • Small sample sizes and/or study durations
  • Lack of human subjects
  • Low-quality study material

But even assuming that scientists could study cannabis as easily as they study corn or soybeans, they would still often arrive at different conclusions depending on their methodologies and other factors. This variability is just more pronounced when it comes to cannabis because the overall pool of studies is much smaller.

For example, even the seemingly-niche research subject of cannabis and dementia has yielded widely different results.

Some Studies Show Cannabis Could Be Useful in Treating Dementia

In 2019, a human study in the journal Medical Cannabis and Cannabinoids found that a cannabinoid-based medication could be effective in treating patients with dementia. Using an oral medication with a roughly 2:1 CBD-to-THC ratio, researchers observed that the subjects — ten women with severe dementia — showed a significant improvement in their symptoms over an extended period (two months). Half of the patients were able to reduce or eliminate their use of other medications, with no major side effects from the new one. As a result, the researchers concluded that the cannabis-based medication “was well tolerated and greatly improved behavior problems, rigidity, and daily care in severely demented patients.”

This echoed the findings of a 2016 study in the Journal of Alzheimer’s Disease. In that study, 11 patients with Alzehimer’s were treated with medical cannabis oil containing THC. Over the four week course of the trial, the researchers noted that “[delusions], agitation/aggression, irritability, apathy, sleep and caregiver distress” were all significantly decreased. This led them to suggest that medical cannabis oil “is safe and a promising treatment option” for people living with Alzheimer’s disease.

Despite these encouraging findings, though, the full picture of cannabis-related dementia research is a bit more complicated.

However, Some Studies Suggest Otherwise

While some studies have found that cannabis can have a positive impact on people with dementia, others have suggested that it doesn’t do much of anything — or in some cases, even worsens side effects.

In 2017, Alzheimer’s and Dementia, the official journal of the Alzheimer’s Association, published a research review of the available studies on cannabis and dementia. What they found was a mixed bag. Out of five total studies, two found that cannabis-based medicine led to no significant improvements in patients’ symptoms, while the other three showed “variable and inconsistent improvements.” In one study, the use of a synthetic cannabis medicine called Dronabinol caused a grand mal seizure and a series of serious infections among patients.

According to the authors of the review, “The currently available examined evidence is weak and limited. It would be premature to say that the cannabis [sic] and related compounds have any effect on dementia symptoms or progression.”

Should you be wondering if things have changed much since 2017, the answer is no. Today when you visit the “Cannabis, CBD oil and dementia” page of the U.K.’s Alzheimer’s Society, the first thing you’ll see is a prominent warning:

“Currently there is no evidence to show that cannabis or cannabis oil (CBD oil) can stop, reverse or prevent dementia.”

The Bottom Line on Cannabis Research

Still, saying that there’s currently a lack of evidence to suggest that cannabis can be useful for treating dementia (or any other condition) is far different from saying that the plant couldn’t potentially be a valuable tool for doctors, patients, and their families. Prior to 2007, there was no evidence to suggest that iPhones would soon change almost every aspect of modern life, yet here we are.

What’s often lost in the high-stakes public discussion over the relative merits (or failings) of a certain cannabis study is the impact on ordinary people. This is why keeping an even-minded view of the latest breaking news is so important — inflating or dismissing the findings of a given study can have consequences for people living with conditions like dementia, as well as those who care for them.

Dr. Amanda Timmler, the lead researcher of the University of Notre Dame Australia’s cannabis and dementia study, described the human impetus behind her work in an email to Cannabis Business Times. “I am interested in how this medication can help to treat dementia as it is a complex condition, with no cure,” she wrote. “The number of family members that I have spoken to since the start of this project who just want someone to talk to is overwhelming as the medication [sic] being used do not always work or make symptoms worse.”

Rome wasn’t built in a day, and neither will the field of cannabis medicine. For now, perhaps the most helpful thing we can do is to quit over-analyzing each new brick as it’s added to the wall.

Mary Sauer
Mary Sauer
Mary Sauer is a Kansas City-based writer with work appearing in Parade, Vice’s Tonic, and Remedy Review. She writes about mental health, cannabis, and parenting.


  1. Alex says:

    Obtaining this approval confirms that an appropriate plan to protect the rights and welfare of human research subjects has been outlined in the proposed research efforts. If a study is being conducted in a clinical research center, a separate review may be required by this entity’s medical or research advisory committee. In summary, basic and clinical researchers seeking to obtain cannabis or cannabinoids from NIDA for research purposes including efforts to determine the value of cannabis or cannabinoids for treating a medical condition or achieving a therapeutic end need must obtain a number of approvals from a range of federal, state, or local agencies, institutions, or organizations. This process can be a daunting experience for researchers. The substantial layers of bureaucracy that emerge from cannabis’s Schedule I categorization is reported to have discouraged a number of cannabis researchers from applying for grant funding or pursuing additional research efforts ( Nutt et al., 2013 ). Given the many gaps in the research of the health effects of cannabis and cannabinoids, there is a need to address these regulatory barriers so that researchers will be better able to address key public health questions about the therapeutic and adverse effects of cannabis and cannabinoid use.

  2. Ramon says:

    The methodological challenges and the regulatory, financial, and access barriers described above markedly affect the ability to conduct comprehensive basic, clinical, and public health research on the health effects of cannabis use, with further consequences for the many potential beneficiaries of such research. In the absence of an appropriately funded and supported cannabis research agenda, patients may be unaware of viable treatment options, providers may be unable to prescribe effective treatments, policy makers may be hindered from developing evidence-based policies, and health care organizations and insurance providers lack a basis on which to revise their care and coverage policies. In short, such barriers represent a public health problem. See Box 15-2 for a summary of the chapter conclusions. Abrams DI, Vizoso HP, Shade SB, Jay C, Kelly ME, Benowitz NL. Vaporization as a smokeless cannabis delivery system: A pilot study.