Hypotheses on Mechanisms of Action

The mechanisms of action of anxiety medications are unknown. However, two hypotheses on how medications alleviate anxiety symptoms involve the serotonin and GABA-BZ neurotransmission systems.

The serotonin system is supposed to be one of the mediators of a “fear network,” which involves the brainstem, the hypothalamus, and the amygdala. The amygdala is a critical temporal lobe structure associated with the expression of anxiety and mammalian stress responses. It is hypothesized that medications influencing the serotonin system desensitize the “fear network” (Gorman, Kent, Sullivan, & Coplan, 2000).

The GABA system has an inhibitory function on the brain. When its function is enhanced by coupling of the BZs with the GABA-BZ receptors on surfaces of neurons, neurotransmissions are inhibited in most parts of the brain. Thus, some over excitation can be leveled off to aid relaxation.