In psychology and substance use research, when an individual such as Dhruv reports needing to consume more alcohol to achieve the same euphoric effect, this phenomenon is known as Tolerance. Tolerance develops when the body adapts to a substance through extended use, requiring a higher dosage to produce the original effects. This physiological adaptation is characteristic of continued substance use and signifies a decreasing bodily response to the substance over time.
Evaluating the provided options:
Therefore, the phenomenon Dhruv is experiencing is best described as tolerance.