What is one key characteristic of cross-tolerance?

One key characteristic of cross-tolerance is that it involves increased tolerance to a drug class. This means that if an individual develops tolerance to one substance within a particular group of drugs, that individual may also experience an increased tolerance to other substances in the same group. For instance, if a person becomes tolerant to the effects of alcohol, they may also find that they have a greater tolerance to benzodiazepines, as both belong to the central nervous system depressants category. This phenomenon occurs because the body adapts to the effects of these drugs in similar ways.

The other options do not accurately describe cross-tolerance. Strong emotional dependence on a drug pertains more to addiction and psychological aspects rather than tolerance. Tolerance developing only with one specific drug would contradict the concept of cross-tolerance, which implies a relationship between multiple drugs. Lastly, the absence of physical withdrawal symptoms is not characteristic of cross-tolerance, as withdrawal symptoms are tied to dependence and might still occur when switching between substances in cases of cross-tolerance.