What type of effect does drug use have at an individual level?

The answer identifies health effects as the type of impact drug use has at an individual level, which is fundamentally correct. Drug use can significantly affect an individual's physical health, leading to medical conditions such as addiction, respiratory issues, cardiovascular problems, and in severe cases, overdose. Additionally, there are mental health implications, including anxiety, depression, or exacerbation of pre-existing mental health issues.

When focusing on individual health, drug use may result in a cascade of consequences that can affect one's overall well-being, ability to function in daily life, and long-term health prospects. Health effects not only encompass the immediate consequences but can also include chronic health issues that emerge from prolonged substance use. The emphasis on health captures the intimate and often personal ramifications that drugs can have on an individual, distinguishing it from broader cultural, environmental, or economic effects that, while relevant, do not directly address individual experiences.