Actions of delta-9-tetrahydrocannabinol in cannabis: Relation to use, abuse, dependence

Summary & key facts

This paper reviews research on how THC, the main psychoactive part of smoked cannabis, works in the brain and how it can lead to dependence. It explains that THC’s pleasurable effects are driven by a brain protein called the CB1 receptor. The same CB1 receptor is linked to withdrawal symptoms when use stops, a pattern seen in different species. The review also notes that the brain’s opioid system can change how THC causes reward and dependence. Together, these findings help explain why some people try to quit cannabis but have trouble staying abstinent.

Key facts:

• Some people who smoke cannabis seek treatment, but only a small number manage to stay abstinent in the long term.
• The pleasurable and reinforcing effects of THC are caused by activity at the brain’s CB1 receptor. The CB1 receptor is a protein on brain cells that responds to THC.
• The CB1 receptor also plays a role in dependence and in the appearance of withdrawal symptoms when cannabis use stops.
• Withdrawal linked to stopping cannabinoids has been observed across species, meaning researchers have seen similar signs in different animals and models.
• The brain’s opioid system can modify how THC produces reward and dependence, so these two brain systems interact.
• The paper reviews behavioral studies of externally supplied cannabinoids, focusing on dependence and reinforcement — the factors that help explain continued cannabis smoking despite harm.

Abstract

Cannabis use disorders have been recently identified as a relevant clinical issue: a subset of cannabis smokers seeks treatment for their cannabis use, yet few succeed in maintaining long-term abstinence. The rewarding and positive reinforcing effects of the primary psychoactive component of smoked cannabis, delta-9-tetrahydrocannabinol (THC) are mediated by the cannabinoid CB1 receptor. The CB1 receptor has also been shown to mediate cannabinoid dependence and expression of withdrawal upon cessation of drug administration, a phenomenon verified across species. This paper will review findings implicating the CB1 receptor in the behavioural effects of exogenous cannabinoids with a focus on cannabinoid dependence and reinforcement, factors that contribute to the maintenance of chronic cannabis smoking despite negative consequences. Opioidergic modulation of these effects is also discussed.

Topics

Cannabis and Cannabinoid Research Forensic Toxicology and Drug Analysis Neurotransmitter Receptor Influence on Behavior

Categories

Health Sciences Medicine Pharmacology

Tags

Abstinence Addiction Antagonist Cannabidiol Cannabinoid Cannabinoid receptor Cannabis Cannabis Dependence Delta-9-tetrahydrocannabinol Drug Endocannabinoid system Internal medicine Medicine Neuroscience Pharmacology Psychiatry Psychology Receptor Tetrahydrocannabinol

Substances

Cannabis

Conditions & symptoms

Addiction Substance abuse disorder Addiction or harmful habbits