What is a key characteristic of anti-anxiety medications?

A key characteristic of anti-anxiety medications is that they are habit-forming. These medications, particularly benzodiazepines, are often prescribed for their calming effects and can lead to physical dependence if used over a prolonged period or at high doses. When patients rely on these medications to manage anxiety, they may experience withdrawal symptoms if they attempt to stop taking them suddenly, reinforcing the potential for habit formation.

The other choices, while related to different types of medications or physiological responses, do not accurately describe the primary concern associated with anti-anxiety medications. For instance, enhancing the body's physical response to stress is contrary to the purpose of these medications, which aim to reduce such responses. Blocking neurotransmitter synthesis is not a typical mechanism of anti-anxiety medications, as they usually function by enhancing the effect of neurotransmitters like GABA to produce a calming effect. Inducing hyperactivity does not align with the intended use of these medications, as they are designed to alleviate anxiety and promote relaxation, not increase activity levels.