Contents lists available at ScienceDirect Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad Research paper Impulsive suicide attempts among young people–A prospective multicentre cohort study in Sweden K. Beckman a, ⁎ , A.U. Lindh a , M. Waern b , L. Stromsten c , E.S. Renberg c , B. Runeson a , M. Dahlin a a Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, & Stockholm Health Care Services, Stockholm City Council, St. Goran, SE-112 61, Stockholm b Department of Psychiatry and Neurochemistry, University of Göteborg, Sweden c Department of Clinical Sciences, University of Umeå, Sweden ARTICLE INFO Keywords: Suicide Young Suicide attempt Cohort study Mental illness ABSTRACT Background: We aimed to compare the prevalence of impulsive suicide attempts (ISA) among young adults and those over 25 who present at hospital in connection with attempted suicide. We also aimed to identify factors associated with ISA in young adults and to assess medical severity as well as the probability of repeated suicide attempts in this age group. Method: A prospective multicentre cohort study included hospital known cases of suicide attempt (N = 666). The prevalence of ISA was compared between young adults (18–25) and adults aged > 26. We used logistic regression models to identify factors associated with ISA, associations of ISA with high medical severity and prediction of new fatal or non-fatal suicide attempts within 6 months. Results: 43.7% of the young patients had made an ISA, and 30.2% among those aged > 26 (p = 0.001). Among the young, substance use disorder was associated with ISA; crude odds ratio (OR) 2.0 (1.0–4.2), and adjusted OR 2.1 (0.99–4.4). Affective disorder and unemployment/ sickness absence implied lower odds of ISA. ISA resulted in injuries of high medical severity as often as more planned attempts and non-fatal or fatal repetition within 6 months was equally common (30%) in both groups. Limitations: The study was set in psychiatric emergency services, which limits the generalizability. Conclusions: Clinicians should acknowledge that suicide attempts among youth often occur without previous planning and may result in medically severe injuries. The probability of new fatal or non-fatal suicide attempts should be kept in mind also after an impulsive suicide attempt. 1. Introduction Self-harm and suicidal behaviour are common in young people; hence, prevention of fatal and non-fatal suicidal events is a target for mental health improvement strategies. When performing risk assess- ments, clinicians often focus on the presence of suicidal planning where the suicidal act is considered to be the end of a pathway, through a continuum of suicidal feelings (Paykel et al., 1974; O'Connell et al., 2004). However, many suicidal acts have not been planned, and should be considered as impulsive acts (Rimkeviciene et al., 2015). There are indications that impulsive suicidal behaviour is more common among young people (Conner et al., 2005; Conwell et al., 1998; Hawton et al., 2005). These findings are, however, contradicted by other studies (Deisenhammer et al., 2009; Conner et al., 2007; Baca-Garcia et al., 2001). Research on the prevalence of impulsive suicidal behaviour in young people can inform the development of targeted preventive stra- tegies. In clinical assessment, it would be useful to distinguish between those who are at risk of making impulsive suicide attempts (ISA) from those with a longer duration of ideation prior to the act, where there is likely to be a longer window of intervention possibilities. Impulsive attempts are associated with lower levels of depression in most studies (Simon et al., 2001; Brown et al., 1991; Baca-Garcia et al., 2005), but not other (Conner et al., 2005). Female gender (Conner et al., 2005) and experience of physical fights (Simon et al., 2001) have been associated with impulsive attempts, while the evidence is mixed regarding alcohol intake (Bagge et al., 2013; Baca-Garcia et al., 2001). Impulsivity is as- sociated with self-harm in young people (Lockwood et al., 2016; https://doi.org/10.1016/j.jad.2018.09.070 Received 28 May 2018; Received in revised form 12 August 2018; Accepted 16 September 2018 Abbreviations: ISA, impulsive suicide attempt; NSSI, non-suicidal self-injury; SIS, suicide intent scale; C-SSRS, Columbia suicide severity rating scale; KIVS, Karolinska interpersonal violence scale ⁎ Corresponding author. E-mail address: karin.beckman@ki.se (K. Beckman). Journal of Affective Disorders 243 (2019) 421–426 Available online 17 September 2018 0165-0327/ © 2018 Elsevier B.V. All rights reserved. T