Conjunctival injection and increased appetite are symptoms commonly associated with which substance?

Conjunctival injection, or redness of the eyes, along with increased appetite, are symptoms that are commonly associated with marijuana use. THC, the psychoactive compound in marijuana, causes vasodilation of the conjunctival blood vessels, leading to the characteristic red eyes. Additionally, marijuana is well-known for its effect on appetite stimulation, often referred to as "the munchies," where users experience an increased desire to eat.

This combination of eye redness and increased appetite is particularly distinct to marijuana, making it a key indicator when evaluating potential substance use. Other substances listed, like heroin, cocaine, and LSD, present with different signs and symptoms; for instance, heroin may cause sedation, while cocaine is associated with increased energy and pupil dilation. This specificity makes marijuana the correct choice for the symptoms described.