biostudies-literatureUnknown228(3)Myhre MO<h4>Background</h4>Self-harm, self-poisoning or self-injury, irrespective of the motivation, is a central risk factor for suicide. Still, there is limited knowledge of self-harm among patients with substance use disorders (SUDs) who die by suicide.<h4>Aims</h4>We aimed to describe the prevalence of a history of self-harm and identify the factors associated with self-harm, comparing individuals who died by suicide with and without SUDs.<h4>Method</h4>We used data from the Norwegian Surveillance System for Suicide in Mental Health and Substance Use Services, which is based on a national linkage between the Norwegian Cause of Death Registry and the Norwegian Patient Registry, to identify individuals who died by suicide within 1 year after last contact with mental health or substance use services (<i>n</i> = 1140). A questionnaire was retrieved for 1041 (91.3%) of these individuals. We used least absolute shrinkage and selection operator (LASSO) regression to select variables and compared patients with and without SUDs. Conditional selective inference was used to improve 90% confidence intervals and <i>p</i>-values.<h4>Results</h4>The prevalence of self-harm was 55% in patients with SUDs and 52.6% in patients without SUDs. Suicidal ideation (odds ratio 2.98 (95% CI 1.74-5.10)) emerged as a factor shared with patients without SUDs, while personality disorders (odds ratio 1.96 (1.12-3.40)) and a history of violence (odds ratio 1.86 (1.20-2.87)) were unique factors for patients with SUDs.<h4>Conclusions</h4>A history of self-harm is prevalent in patients with SUDs who die by suicide and is associated with suicidal ideation, a history of violence and personality disorders in patients with SUDs.The British journal of psychiatry : the journal of mental science229-235https://www.ebi.ac.uk/biostudies/studies/S-EPMC12912876biostudies-literatureFactors associated with self-harm in patients with substance use disorders who died by suicide: national hybrid questionnaire registry study.PMC12912876Mehlum LBramness JGWalby FAKlungsoyr OMyhre MOfalseFactors associated with self-harm in patients with substance use disorders who died by suicide: national hybrid questionnaire registry study.<h4>Background</h4>Self-harm, self-poisoning or self-injury, irrespective of the motivation, is a central risk factor for suicide. Still, there is limited knowledge of self-harm among patients with substance use disorders (SUDs) who die by suicide.<h4>Aims</h4>We aimed to describe the prevalence of a history of self-harm and identify the factors associated with self-harm, comparing individuals who died by suicide with and without SUDs.<h4>Method</h4>We used data from the Norwegian Surveillance System for Suicide in Mental Health and Substance Use Services, which is based on a national linkage between the Norwegian Cause of Death Registry and the Norwegian Patient Registry, to identify individuals who died by suicide within 1 year after last contact with mental health or substance use services (<i>n</i> = 1140). A questionnaire was retrieved for 1041 (91.3%) of these individuals. We used least absolute shrinkage and selection operator (LASSO) regression to select variables and compared patients with and without SUDs. Conditional selective inference was used to improve 90% confidence intervals and <i>p</i>-values.<h4>Results</h4>The prevalence of self-harm was 55% in patients with SUDs and 52.6% in patients without SUDs. Suicidal ideation (odds ratio 2.98 (95% CI 1.74-5.10)) emerged as a factor shared with patients without SUDs, while personality disorders (odds ratio 1.96 (1.12-3.40)) and a history of violence (odds ratio 1.86 (1.20-2.87)) were unique factors for patients with SUDs.<h4>Conclusions</h4>A history of self-harm is prevalent in patients with SUDs who die by suicide and is associated with suicidal ideation, a history of violence and personality disorders in patients with SUDs.2026-01-01T00:00:00Z2026 Mar2026-07-16T00:31:08.15Z2026-07-09T13:09:43.201ZS-EPMC129128764014367810.1192/bjp.2025.22