Which of the following is a hallmark symptom of diabetes mellitus?

Increased thirst, or polydipsia, is indeed a hallmark symptom of diabetes mellitus. This occurs as a result of elevated blood glucose levels, which lead to osmotic diuresis. When glucose spills over into the urine, it draws water along with it, resulting in increased urine production (polyuria). This loss of water leads to dehydration, which in turn stimulates the thirst center in the brain, causing individuals to experience excessive thirst.

This symptom often arises alongside other classic symptoms of diabetes, such as increased urination and increased hunger. Understanding this symptom is crucial for recognizing diabetes and initiating timely management to prevent possible complications related to the condition.