Background: Patients with psychiatric disorders have a high rate of suicide. The present study investigated factors influencing hospital stays for Japanese patients with psychiatric disorders attempting suicide by jumping. Methods: We diagnosed all suicide attempts (n = 113) by jumping based on the International Classification of Diseases 10th Revision (ICD-10) and investigated the mean hospital stays of patients with each diagnosis based on the ICD-10 code. We then analyzed differences in the demographic and clinical characteristics between the diagnostic groups to identify factors influencing the duration of hospital stay. Results: Patients diagnosed with schizophrenia (F2 code) were the most frequent (32.7%) of all diagnoses; therefore, we divided the diagnostic groups into schizophrenia group (n = 37) and other psychiatric diagnoses group (n = 76). The patients with schizophrenia showed a significantly longer hospital stay (125.7 +/- 63.9 days) compared with the patients with other psychiatric diagnoses (83.6 +/- 63.2) (beta +/- SE = 42.1 +/- 12.7, p = 0.0013), whereas there was no difference in the jump height between the two groups (the average was the 3rd to 4th floor; p >0.05). The number of injured parts, particularly lower- limb fractures, was significantly higher (p = 0.017) in patients with schizophrenia than in patients with other psychiatric diagnoses. The duration of psychiatric treatment in patients with schizophrenia were significantly longer (z = 3.4, p = 0.001) than in patients with other psychiatric diagnoses. Conclusion: Our findings indicate that the number of injuries and the body parts injured in patients with schizophrenia are associated with a longer duration of hospital stay following a suicide attempt by jumping. The current use of antipsychotics and a longer duration of taking antipsychotics might contribute to the risk of bone fracture via hyperprolactinemia. Further cognitive impairment in patients with schizophrenia might prevent rehabilitation for the management of lower- limb fractures. From these results, we suggest that clinicians should monitor the level of prolactin and cognitive function in patients with schizophrenia in future studies on managing of lower- limb fractures.