Background: To investigate whether schizophrenia patients with both suicide attempts and non-suicidal self-harm have earlier age of onset of psychotic and depressive symptoms and higher levels of clinical symptoms compared to patients with only suicide attempts or without suicide attempt. Methods: Using a cross-sectional design, 251 patients (18–61 years old, 58% men) with schizophrenia treated at hospitals in Oslo and Innlandet Hospital Trust, Norway, were assessed with a comprehensive clinical research protocol and divided into three groups based on their history of suicide attempts and non-suicidal self-harm. Results: Suicide attempts were present in 88 patients (35%); 52 had suicide attempts only (29%) and 36 had both suicide attempts and non-suicidal self-harm (14%). When compared with nonattempters and those with suicide attempts without non-suicidal self-harm, patients with both suicide attempts and non-suicidal self-harm were more frequently women, younger at the onset of psychotic symptoms, had longer duration of untreated psychosis, and had higher levels of current impulsivity/aggression and depression. Patients with both suicide attempts and non-suicidal self-harm were more likely to repeat suicide attempts than patients with suicide attempts only. Conclusions: Patients with both suicide attempts and non-suicidal self-harm had different illness history and clinical characteristics compared to patients with only suicide attempts or patients without suicidal behavior. Our study suggests that patients with both suicide attempts and non-suicidal self-harm represent a distinct subgroup among patients with schizophrenia and suicidal behavior with their early onset of psychotic symptoms, high rate of repeated suicidal behavior and significant treatment delay. © 2013 Mork et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License.