Which characteristic defines medications classified under Schedule 3?

Medications classified under Schedule 3 are defined by their potential for moderate to low physical dependence and high psychological dependence. This classification accounts for substances that have legitimate medical uses but also pose a risk for abuse.

The moderate to low physical dependence means that, while withdrawal symptoms can occur, they are generally less severe than those seen with Schedule 1 or 2 substances. The high psychological dependence indicates that patients can become psychologically reliant on these medications, which can lead to misuse.

In contrast, the other options indicate characteristics that do not apply to Schedule 3 medications. For instance, these medications can indeed be prescribed by healthcare providers, and they are not illegal, as they have recognized medical applications. While some Schedule 3 medications may be obtained with a prescription, they are not available without one, making the option about availability without a prescription inaccurate in this context.