A patient presents with euphoria, glassy red eyes, loud talking, dry mouth, excessive hunger, and sleepiness. What is the likely substance of intoxication?

The symptoms described in the scenario—euphoria, glassy red eyes, loud talking, dry mouth, excessive hunger, and sleepiness—are indicative of marijuana intoxication. One of the hallmark signs of marijuana use is the presence of glassy or bloodshot eyes due to its effects on the blood vessels. Euphoria is also a common psychosocial effect associated with marijuana, often paired with increased sociability, which can explain the loud talking.

The dry mouth, often referred to as "cottonmouth," and the increased appetite, commonly known as "the munchies," further solidify the likelihood of marijuana as the substance involved. Additionally, the sleepiness can occur due to the sedative properties of marijuana, especially in higher doses.

In contrast, other substances listed produce different symptom profiles. Alcohol may present with euphoria and impaired judgment but would more typically be associated with slurred speech and lack of coordination. PCP can cause significant agitation or dissociation that does not align with the sleepy behavior observed here. Cocaine is a stimulant that typically leads to increased energy, alertness, and hyperactivity, differing significantly from the sleepiness noted in the patient. Thus, the overall presentation aligns most closely with intoxication from marijuana.