Which symptom is unlikely to be associated with hyperthyroidism caused by Graves' disease?

In the context of hyperthyroidism, particularly caused by Graves' disease, the body experiences an overproduction of thyroid hormones, leading to an increased metabolic rate. This condition is typically associated with a range of symptoms reflecting this hypermetabolic state.

Increased sweating, palpitations, and nervousness are all common symptoms of hyperthyroidism. Increased sweating occurs due to heightened metabolism and thermogenesis. Palpitations are a consequence of an increased heart rate often seen in hyperthyroid patients. Nervousness or anxiety is frequently reported, as the overstimulation of the nervous system from elevated thyroid hormone levels can lead to heightened anxiety and restlessness.

In contrast, weight gain is unlikely to be associated with hyperthyroidism caused by Graves' disease. In fact, patients with this condition typically experience weight loss despite an increased appetite due to the accelerated metabolic processes. Therefore, weight gain does not fit the symptom profile of hyperthyroidism, making it the correct answer in this scenario.