Dr. Matthew Hill: How Cannabis Impacts Health & the Potential Risks

Cannabis: A Deeper Dive with Dr. Matthew Hill

In this fascinating episode of the Huberman Lab podcast, Andrew Huberman dives into the world of cannabis with Dr. Matthew Hill, a professor of Cell Biology and Anatomy at the University of Calgary. Dr. Hill, known for his expertise in the biology of cannabis, brings a wealth of knowledge and research experience to the conversation, offering valuable insights into the complex effects of this widely used substance.

Core Concepts and Philosophies

The podcast centers around the intricate biological mechanisms of cannabis, focusing on how it interacts with the brain and body. Key concepts discussed include:

• The Endocannabinoid System: Dr. Hill emphasizes the importance of the endocannabinoid system, a network of receptors and neurotransmitters naturally present in the body, responsible for regulating various functions like mood, appetite, and pain. He explains that THC mimics the actions of these endogenous cannabinoids, leading to the psychoactive effects associated with cannabis.
• Retrograde Signaling: He highlights the unique retrograde signaling mechanism of endocannabinoids, where they are produced in the postsynaptic neuron and travel back to the presynaptic neuron to regulate neurotransmitter release. This contrasts with traditional anterograde signaling, where neurotransmitters are released from the presynaptic neuron and act on the postsynaptic neuron.
• Homeostasis and Plasticity: Dr. Hill explains how the endocannabinoid system plays a critical role in maintaining homeostasis, ensuring that brain circuits remain in a balanced state. This regulatory function extends to neuroplasticity, allowing for the strengthening or weakening of synapses based on experience and learning.

Practical Strategies and Advice

Dr. Hill offers crucial advice for understanding and navigating cannabis use:

• Proceed with Caution: Due to the complex and variable nature of cannabis effects, Dr. Hill strongly advocates for a cautious approach, emphasizing the importance of starting with low doses and gradually increasing as needed. He stresses the unpredictability of high THC concentrations and the potential for adverse reactions, particularly in individuals with pre-existing conditions like schizophrenia or bipolar disorder.
• Understand Dose and Time Course: He emphasizes the significant differences in dosage and time course between inhalation and oral consumption. Inhalation leads to rapid absorption and a relatively short-lived high, allowing for easier titration. Oral consumption, on the other hand, results in slower absorption and a prolonged high, making overconsumption more likely and potentially leading to unexpected and unwanted effects.
• Be Aware of Potential Harms: Dr. Hill outlines the potential harms of cannabis use, including the risk of psychosis in individuals with a predisposition to schizophrenia or bipolar disorder, impaired cognitive function, particularly memory, and cardiovascular issues. He advises individuals with these conditions to avoid cannabis altogether.
• Consider Alternatives: He suggests exploring alternative methods for managing anxiety and sleep issues, such as breathwork, meditation, or cognitive behavioral therapy, which have strong scientific support and may offer a safer and more effective approach.
• Question Unverified Claims: Dr. Hill highlights the abundance of anecdotal evidence and marketing claims surrounding cannabis strains and the Entourage Effect. He emphasizes the need for blinded studies and controlled trials to validate these claims and provide reliable information about the potential benefits and risks of specific cannabinoids and terpene combinations.
• Be Informed about CBD: He points out that CBD is largely absent from street cannabis due to breeding practices favoring THC production. He explains that CBD has limited interactions with the CB1 receptor and its effects are likely mediated through other mechanisms, including adenosine inhibition. He cautions against overreliance on CBD products, particularly those with high doses, due to the potential for liver enzyme saturation and interactions with other medications.

Supporting Evidence

Dr. Hill references numerous studies, including those conducted by his own lab, to support his insights. He specifically mentions:

• Research on the Endocannabinoid System: He refers to studies that have established the crucial role of the endocannabinoid system in maintaining homeostasis and modulating brain activity, particularly in areas related to mood, appetite, pain, and memory.
• Studies on the Effects of THC: He highlights research demonstrating the psychoactive effects of THC, its interactions with CB1 receptors, and the potential for THC to induce psychosis in individuals with a predisposition to mental health disorders. He also mentions research investigating the effects of THC on appetite, sleep, and pain perception.
• Studies on the Effects of CBD: Dr. Hill cites research highlighting the efficacy of high doses of CBD in managing certain types of pediatric epilepsy. He also refers to studies that have investigated CBD's interactions with the adenosine system and its potential for reducing inflammation.
• Research on the Entourage Effect: He acknowledges emerging research exploring the potential impact of terpene combinations on THC's effects, such as the study by Ryan Vandrey et al. showing that limonene can reduce anxiety associated with high doses of THC.

Personal Application

Dr. Hill applies his knowledge of cannabis to his own life by:

• Avoiding Cannabis: Dr. Hill personally avoids cannabis due to his awareness of the potential risks associated with its use, especially given his research interests in areas like stress, anxiety, and mental health.
• Promoting Informed Choice: He leverages his understanding of the complex biology of cannabis to inform his approach to research, patient education, and public health communication. He strives to promote informed decision-making regarding cannabis use, emphasizing the need for caution, balanced information, and awareness of potential harms.

Recommendations for Tools and Techniques

Dr. Hill recommends the following tools and techniques for navigating cannabis use:

• Lower Risk Cannabis Use Guidelines: He suggests consulting the Lower Risk Cannabis Use Guidelines developed by the Centre for Addiction and Mental Health in Canada, which provide evidence-based recommendations for reducing potential harms associated with cannabis use.
• Start Low and Go Slow: He encourages individuals considering cannabis use to begin with low doses and gradually increase as needed, allowing for proper titration and minimizing the risk of adverse effects.
• Explore Alternatives: He recommends exploring evidence-based alternatives to cannabis for managing anxiety and sleep issues, such as breathwork, meditation, and cognitive behavioral therapy. He believes these approaches may offer greater safety and effectiveness.
• Question Marketing Claims: Dr. Hill urges consumers to approach marketing claims about specific strains and the Entourage Effect with skepticism, seeking evidence-based information from reputable sources.