Which of the following can be classified directly under substance misuse?

The classification of substance misuse encompasses actions that involve the inappropriate or harmful use of substances, particularly those that can lead to negative consequences for the individual or society. The option referring to the inappropriate use of prescribed medications fits this definition well. It highlights a scenario where medication, which may be intended to treat a medical condition, is taken in a manner not prescribed by a healthcare provider, potentially leading to misuse and harmful effects.

In contrast, casual drinking in social settings typically does not indicate misuse if it falls within low-risk guidelines. Regular exercise and balanced nutrition are positive lifestyle choices that promote health and wellness, and do not relate to the concept of misuse at all. Therefore, the option regarding the inappropriate use of prescribed medications is the only choice that clearly aligns with the definition of substance misuse, making it the correct answer.