PRL and hyperprolactinemia: Further, two forms of potential bias may occur in association with risperidone treatment: (1) patients may be more likely to undergo testing for prolactin elevation, regardless of the prior presence of PPAEs, leading to a diagnosis of hyperprolactinemia that otherwise may have remained clinically silent; and (2) risperidone-treated patients, particularly those with PPAEs, may be more likely to undergo investigation that could result in an incidental diagnosis of benign pituitary tumors.