Post by Asha Powell-Stormberg, undergraduate in Science pursuing an Interdisciplinary Neuroscience minor at Portland State University. Asha is a regular contributor to outreach visits through Northwest Noggin, and is currently interning in Dr. Adie Rae Wilson-Poe’s cannabinoid research lab at Legacy Research Institute.
I am a senior at Portland State University about to graduate in June. For the last few months I’ve been exploring research on the effects of cannabis vaporizers, reviewing all the different studies that have been published not only on the vaporization of cannabis, but also on federal drug regulations, carcinogens found in cannabis, cannabis smoke versus vaping, and much more.
Fred Tomaselli, Super Plant, 1994. Psychoactive plant material, acrylic, resin on wood panel, 74 x 54″
LEARN MORE: Cannabis legalization in the US. Where do we go from here?
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What is Literature Review?
Literature review is an important part of the research process. It is also, I’ve found, a time consuming activity where you read through hundreds of research articles on various subjects related to what you are trying to write a formal review paper about.
LEARN MORE: Approaching literature review for academic purposes
LEARN MORE: Ten Simple Rules for Writing a Literature Review
LEARN MORE: Writing an Effective Review Article
LEARN MORE: Basics of Writing Review Articles
This process starts with an idea.
In my case the researcher I am working with, Dr. Adie Rae Wilson-Poe at Legacy Research Institute in Portland, Oregon, studies the efficacy of cannabis vaporization as a treatment for reducing chronic pain.
“The central hypothesis of Dr. Wilson-Poe’s work is that cannabis and cannabinoids can be leveraged for their pain-relieving and harm-reducing properties, to reduce societal dependence upon opioids.”
— Adie Rae Wilson-Poe
LEARN MORE: Adie Rae (Wilson-Poe), Ph.D.
LEARN MORE: The Nose Knows: Aroma, but Not THC Mediates the Subjective Effects of Smoked and Vaporized Cannabis Flower
LEARN MORE: Emerging Evidence for Cannabis’ Role in Opioid Use Disorder
LEARN MORE: A Legacy of Links
Then it’s time to read!
So…I started diving into various online search engines for research papers such as PUBMED and GOOGLE SCHOLAR to find all the published, peer-reviewed information on cannabis, including analysis of risks versus benefits, vaping versus smoking, abuse liability, inhalation safety, federal bans on e-cigarettes and so much more.
To put it plainly I have reviewed over 200 research articles to pull out about 60 to put into my own review paper to be published.
LEARN MORE: Now More Than Ever: Reflections on the State and Importance of Peer Review
LEARN MORE: Neuroscience Information Network (NIF)
Why is this important?
In order to receive grant funding to research you must show that there is a need for that research to be done. Literature review helps find areas where more research is necessary in a given area of study and allows us to write a review paper that can be used to ask for grants.
Learning to search
Understanding how to use these search engines can increase your success in finding what you are looking for.
These search engines allow you to choose specific types of articles you are looking for. For example, when searching PubMed, if you are in need of some clinical trials you check the clinical trial box on the left hand side of the screen to only see articles for the search topic that are clinical trials. You can also look by year, full paper, abstract only, and so much more.
Another cool tip I learned: If you find an article you like you can also click on the name of the author (use the last name listed as this is usually the primary researcher) to find more articles written by them.
Exploring “similar articles” can offer more information or help you locate older articles that might give you a more complete understanding of your topic. But be careful because this is how you can find those rabbit holes to go down that can take you off track!
For example, while I was looking into the risks of developing a cannabis use disorder I found a ton of additional papers on how cannabis affects fetal development in pregnant women. While this information really interests me and is certainly beneficial, it is not the main focus of my paper.
Keep it organized
Organization is key to keeping track of topics and headings that you have searched for as well as keeping the data for your paper in one accessible location.
You might not use all of the sources you have cataloged in your reviewing quest. That list of articles is a resource for when you are ready to start your paper outline. At that point you must decide which of the hundreds of papers you’ve referenced and read will be the most useful in a published review.
As I went through the articles I would put their findings into a spreadsheet where I listed the search term, the ID# for the article, and its main results. This allowed me to quickly find the article for further review and know what specifically useful information I might add to my own paper.
A REMINDER: it is very, very easy to go down a compelling, intriguing rabbit hole that in the end may not be needed or valuable for the paper you are trying to write!
After weeks of reviewing papers, it was time to produce my outline. This involved two weeks of editing and moving things around until I felt good about the structure of the paper.
I placed the Article ID number next to each line to ensure that I had the resources necessary to write about that particular topic. When I found gaps I would to go back to my online sources to locate more peer-reviewed references to fill them in.
This whole process of getting the correct information for my particular topic of research is not short or easy. It takes many hours of reading research articles, understanding how to pull out the most pertinent information and read graphs in order to convey my own synthesis in the review paper I am writing.
After all of this hard work it is time to put your research into a paper that will provide a whole picture of the topic and what you know versus what you don’t know. What we don’t know is what is most important as it highlights the fact that more research is needed in order to answer the questions at hand.
My Lit Review
My rationale for this literature review is the following: the quick onset of pain relief from vaporizing cannabis, along with the patient’s ability to self administrate and titrate the dose (i.e., maintain the level the patient feels is helpful) of a potentially more effective and safer drug for the population than opioids could be a much better way to treat people’s pain. However, there are still many unanswered questions to fully understand both benefits and risks of cannabis vapor inhalation.
“Indeed, marijuana is less toxic than many of the drugs that physicians prescribe every day.”
— Dr. Jocelyn Elders, U.S. Surgeon General (1993–94)
Some research is showing that concentrates made out of whole flowers have more therapeutic benefits than more limited cannabinoid drug combinations (e.g., Dronabinol) because additional chemicals (terpenes and flavonoids) contained in the concentrate may contribute to better analgesic and anti-inflammatory effects.
“…extraction of medical Cannabis oils to reach a high yield of Δ9-tetrahydrocannabinol (Δ9-THC), but poor attention has been paid to the preservation of the terpene fraction from the plant, which may contribute to the overall bioactivity of the extracts.”
— Marco Ternelli
LEARN MORE: Antinociceptive effects of minor cannabinoids, terpenes and flavonoids in Cannabis
And now I write!
I start with my own words and write the entire paper except for the conclusion and abstract. Then I go back and I put in the evidence that supports my own summary of the research. This also allows me to see where my research may be lacking. Again, it is important to state where research is not abundant as this provides evidence of the need for more research for funding organizations. Once you have all your evidence put in then you can write your abstract (summary of the review) and your conclusion (summary of your findings and stating of what you know versus what you don’t know).
This experience has given me a better understanding of the time and effort it takes to research and report new reviews and how a review can bring in funding for research.
I’ve found this process rewarding and educational. I’ve learned to properly use online research search engines, get a paper ready for publication and also work with an amazing researcher in a field that I believe is going to potentially improve the way we treat pain.
STAY TUNED: My literature review is on the way!
Some additional research on cannabis
Cannabis neurophysiological effects
LEARN MORE: The endocannabinoid system: emotion, learning and addiction
LEARN MORE: Music, Drugs, Brains & The Beatles!
LEARN MORE: Art, Pain & Cannabinoids: Results from Research
Cannabis use during pregnancy
Cannabis use and opioid dependency reduction
LEARN MORE: Emerging Evidence for Cannabis’ Role in Opioid Use Disorder
Benefits of cannabis use
LEARN MORE: Evaluation and Treatment Of Pain With Medicinal Cannabis
LEARN MORE: Cannabinoids, the endocannabinoid system, and pain: a review of preclinical studies
LEARN MORE: Cannabinoids in the treatment of rheumatic diseases: Pros and cons