What is a common potential side effect of long-term corticosteroid use?

Long-term use of corticosteroids is often associated with weight gain due to several factors. Corticosteroids can lead to increased appetite, changes in fat distribution, and alterations in metabolism. These medications cause the body to retain sodium and water, which can lead to edema and increased body weight. Additionally, corticosteroids can stimulate appetite, leading to increased caloric intake. Over time, these effects contribute to significant weight gain, making it a well-recognized side effect of prolonged corticosteroid therapy.

In contrast, the other options do not align with the typical effects seen with long-term corticosteroid use. Insomnia can occur but is not as common as weight gain. Decreased appetite tends to be the opposite of what is seen in many patients using corticosteroids. Increased energy levels are generally not a direct effect of corticosteroid treatment; in fact, patients may feel more fatigued or experience mood changes instead. Therefore, the most common side effect among the choices provided is indeed weight gain.