Improvement of antipsychotic-induced sexual dysfunction after switching from paliperidone to lurasidone: A case report

Background Sexual dysfunction (SD) is a distressing adverse effect of antipsychotic treatment and is often related to hyperprolactinemia. Paliperidone is a prolactin-elevating agent, whereas lurasidone is relatively prolactin-sparing and has low affinity for receptors implicated in sexual side effects. Because antipsychotic-associated SD is multifactorial, prolactin-independent mechanisms may also contribute. However, case-based evidence documenting outcomes after switching from paliperidone to lurasidone using standardized quantitative measures remains limited. Case Report A 23-year-old man with schizophrenia developed clinically significant SD (reduced libido, erectile dysfunction, and impaired orgasm) while receiving paliperidone 9 mg/day. Baseline serum prolactin was 49.30 ng/mL and the Arizona Sexual Experience Scale (ASEX) total score was 20. A structured cross-titration to lurasidone was completed over 12 weeks. After switching to lurasidone 60 mg/day monotherapy, prolactin was within the reference range at 7.53 ng/mL and the ASEX total score improved to 12, with psychiatric stability maintained. Conclusion This case documents a clinically meaningful improvement in SD during a paliperidone-to-lurasidone switch, accompanied by prolactin normalization. Prolactin normalization may have contributed substantially to the overall improvement, although the domain-specific pattern and single-case design preclude causal attribution and suggest that additional prolactin-independent factors may also have contributed.