However, when patients were grouped according to their prolactin level, the score for short-term memory was 0.98 ± 0.01 in patients with normoprolactinemia, 0.75 ± 0.25 in patients with hyperprolactinemia and 0.63 ± 0.51 in patients with hypoprolactinemia (p = 0.005). This evidence concerns the gene PRL and hyperprolactinemia.