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  1. Good Science Digest

  2. Oct 2, 2018

Cannabis Research in Rats? We Wish We Were Kidding

Recently, researchers from Washington State University reported “breaking” research that found that cannabis use alters eating behaviors, findings which they claim may lead to treatments for appetite loss in chronic illness. 

The study exposed rats to cannabis vapor to assess how the drug affects appetite and triggers hunger hormones. When the rats were forced to inhale cannabis, their brains released a flow of ghrelin, the hunger hormone, which stimulated their appetites and triggered them to eat. The researchers conducted this study in hopes that it would lead to new treatments for illness-induced appetite loss that is common in many chronic illnesses like cancer and HIV/AIDS.

Not only is this research inefficient and unethical, it’s utterly insignificant. Animal research does not translate to knowledge about humans. Not only that, but we already know that, when exposed to cannabis, a human’s hypothalamus triggers the release of ghrelin, which stimulates the appetite. This isn’t new science; this is another example of researchers taking advantage of animals who aren’t protected by the Animal Welfare Act

Unfortunately, studies of this type aren’t isolated events. In 2017, the National Institutes of Health (NIH) supported 330 cannabinoid research projects totaling almost $140 million. Many of these studies involved the use of animals for experimentation, including mice, rats, dogs, and non-human primates. It’s common in these studies that, after being trapped inside inhalation chambers, the animals are killed so that researchers can extract the animal’s organs (typically the brain) to study more closely.  

There are currently 30 states where cannabis is available for use as a therapeutic agent and nine that have approved cannabis for recreational use. With cannabis policy shifting, the number of studies and amount of funding dedicated to scientific research in this area will increase. However, that doesn’t mean animals have to suffer. There are numerous humane and human-relevant alternatives that can be used to address the current research gaps.

In 2017, the National Academy of Sciences (NAS) conducted an extensive review of the current evidence regarding the health effects of using cannabis and cannabis-derived products. In its report, The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research, the committee presents nearly a hundred research conclusions and outlines recommendations to improve future cannabis research. The report concludes that there is limited evidence that cannabis is effective at increasing appetite and decreasing weight loss associated with HIV/AIDS and insufficient evidence that cannabis is an effective treatment for cancer-associated anorexia nervosa.

The NAS committee formulated recommendations to improve the quality and advancement of cannabis research. The experts endorse prioritizing a research agenda to support the investigation of the long- and short-term health effects of cannabis use, using human clinical and epidemiological studies. They also recommend the development of novel diagnostic technologies that permit rapid, accurate, and noninvasive assessment of cannabis exposure. This report demonstrates the need for more human-based research (such as this report) in order to advance our knowledge of cannabis.

Opportunely, other researchers have identified the benefits of conducting more efficient research in humans. According to, there are 437 and 732 current or recently concluded human clinical and observational studies in the United States and worldwide, respectively, investigating cannabis. These types of studies use human volunteers who consent to participate in research in order to make advancements in medical knowledge.

With technology continuously advancing, there is no justification to explain the use of animals to study human diseases. The research at Washington State University that used animals to study how brain changes from cannabis exposure are responsible for changes in eating behavior could have been done with human volunteers. Advanced neuroimaging techniques like functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and positron emission tomography (PET) are able to reveal functional brain activity in response to stimuli, including peripheral signals with central effects (like ghrelin).

With cannabis studies on the rise, researchers and funding bodies must prioritize the use of humans and human-based methods for more promising scientific research.

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