What is a potential consequence of combining stimulants with other substances?

Combining stimulants with other substances can significantly increase the likelihood of overdose, making this the correct answer. Stimulants, such as amphetamines or cocaine, increase heart rate, blood pressure, and can lead to heightened psychological effects. When these are mixed with other substances—especially those that also affect the central nervous system, such as alcohol, sedatives, or other stimulants—the risk of adverse effects is compounded.

For example, using stimulants alongside depressants can lead the individual to consume more of either substance, as the depressant may mask the stimulant's effects. This can result in an overstimulation of the heart or nervous system, which might lead to cardiovascular issues or even fatal overdoses. Therefore, the interaction of stimulants with other drugs poses a significant threat due to unpredictable responses in the body and heightened potential for serious complications.

The other potential outcomes listed, such as enhanced therapeutic effects, reduction in side effects, or no significant effects, tend to underestimate the risks associated with such combinations. In many cases, the combination of substances can lead to dangerous and unintended consequences rather than the beneficial effects that some may anticipate.