Exploring the endocannabinoid system and the biological roots of addiction

What if a medical test could reveal a patient’s risk of developing an addiction, or help identify the best methods to treat them? Dr. Isabelle Boileau’s research into the endocannabinoid system could help us understand the biological underpinnings of addiction, and new ways to treat it.

An Associate Professor in the Department, Boileau has been a researcher at CAMH since 2009 and is currently Scientist and Head, Addiction Imaging Research Group, at CAMH’s Campbell Family Mental Health Research Institute. She has a long history of researching addiction, and most of her work has focused on the dopamine system. The dopamine system is a group of nerve cells that essentially acts as a reward system in the brain, causing sensations of pleasure in response to certain stimuli.

Recent advances in positron emission tomography (PET) scan technology have opened up new possibilities for exploring the mechanics behind addiction in the brain, and allowed researchers like Boileau to go beyond the dopamine system and explore other systems in order to gain a fuller picture of how addiction functions in the brain.

Boileau is now examining the endocannabinoid system and its interactions with the dopamine system. Endocannabinoids are lipid-signaling molecules, chemicals in the brain that are similar in composition to cannabis. Brain endocannabinoid signaling influences the motivation for rewards (such as food and sex) and is believed to modulate the rewarding effects of addictive drugs. It may drive a person to use an addictive substance more or less, and may offer a potential pathway to treatment.

To explore this possibility further, Boileau is measuring the amount of a major enzyme that’s part of the Endocannaboid system, called “FAAH”. FAAH metabolizes cannabis-like substances in the brain, and FAAH levels may contribute to the development of addictions.

“Changes in FAAH levels most likely have complex effects on behavior,” says Boileau, “Lower FAAH may increase the motivation to use drugs, while at the same time it could also reduce symptoms experienced during withdrawal or symptoms that co-occur with addictions, including anxiety and depressed mood.”

Boileau and her team are measuring the amounts of FAAH in people with addictions and people undergoing withdrawal, and attempting to relate FAAH levels with addiction symptoms. Eventually they hope to be able to determine who will benefit from FAAH targeted therapies - for example, if a patient with an addiction should be receiving FAAH inhibitors.

This knowledge could allow physicians to treat patients with addiction or withdrawal more effectively, reducing suffering, cutting costs, and potentially improving outcomes. Ultimately, it could also open the door to developing new treatments, giving us additional options to help people with addictions.