Biphasic Response
A dose-response relationship where low and high doses of a substance produce opposite or qualitatively different effects.
In Depth
THC exhibits a well-documented biphasic response for anxiety: low doses (2.5–5mg) tend to reduce anxiety through CB1-mediated inhibition of amygdala activity, while higher doses (>10mg) frequently increase anxiety and can trigger panic responses. This biphasic pattern is also observed for THC's effects on memory, appetite, and cardiovascular function. Understanding biphasic responses is critical for clinical dosing and explains why recreational and therapeutic dose ranges often differ substantially.
Related Terms
Further Reading
More in Pharmacology
Endocannabinoid System (ECS)
A lipid-based retrograde neurotransmitter system comprising endogenous cannabinoids (endocannabinoids), their receptors (CB1, CB2), and metabolic enzymes.
CB1 Receptor
Cannabinoid receptor type 1. A G protein-coupled receptor (GPCR) primarily expressed in the central nervous system. The primary target of THC's psychoactive effects.
CB2 Receptor
Cannabinoid receptor type 2. A GPCR primarily expressed in immune tissues and peripheral organs. Less abundant in the CNS than CB1.
Anandamide (AEA)
N-arachidonoylethanolamine. The first endocannabinoid identified. A partial agonist at CB1 and CB2 receptors, named from the Sanskrit word "ananda" meaning bliss.
2-Arachidonoylglycerol (2-AG)
The most abundant endocannabinoid in the brain. A full agonist at both CB1 and CB2 receptors.