title: Short-term and long-term effects of psychosocial therapy for people after deliberate self-harm: a register-based, nationwide multicentre study using propensity score matching.
abstract: BACKGROUND
  Although deliberate self-harm is a strong predictor of suicide, evidence for effective interventions is missing. The aim of this study was to examine whether psychosocial therapy after self-harm was linked to lower risks of repeated self-harm, suicide, and general mortality.
  
  
  METHODS
  In this matched cohort study all people who, after deliberate self-harm, received a psychosocial therapy intervention at suicide prevention clinics in Denmark during 1992-2010 were compared with people who did not receive the psychosocial therapy intervention after deliberate self-harm. We applied propensity score matching with a 1:3 ratio and 31 matching factors, and calculated odds ratios for 1, 5, 10, and 20 years of follow-up. The primary endpoints were repeated self-harm, death by suicide, and death by any cause.
  
  
  RESULTS
  5678 recipients of psychosocial therapy (followed up for 42·828 person-years) were matched with 17,034 individuals with no psychosocial therapy in a 1:8 ratio. During 20 year follow-up, 937 (16·5%) recipients of psychosocial therapy repeated the act of self-harm, and 391 (6·9%) died, 93 (16%) by suicide. The psychosocial therapy intervention was linked to lower risks of self-harm than was no psychosocial therapy (odds ratio [OR] 0·73, 95% CI 0·65-0·82) and death by any cause (0·62, 0·47-0·82) within a year. Long-term effects were identified for repeated self-harm (0·84, 0·77-0·91; absolute risk reduction [ARR] 2·6%, 1·5-3·7; numbers needed to treat [NNT] 39, 95% CI 27-69), deaths by suicide (OR 0·75, 0·60-0·94; ARR 0·5%, 0·1-0·9; NNT 188, 108-725), and death by any cause (OR 0·69, 0·62-0·78; ARR 2·7%, 2·0-3·5; NNT 37, 29-52), implying that 145 self-harm episodes and 153 deaths, including 30 deaths by suicide, were prevented.
  
  
  CONCLUSIONS
  Our findings show a lower risk of repeated deliberate self-harm and general mortality in recipients of psychosocial therapy after short-term and long-term follow-up, and a protective effect for suicide after long-term follow-up, which favour the use of psychosocial therapy interventions after deliberate self-harm.
  
  
  BACKGROUND
  Danish Health Insurance Foundation; the Research Council of Psychiatry, Region of Southern Denmark; the Research Council of Psychiatry, Capital Region of Denmark; and the Strategic Research Grant from Health Sciences, Capital Region of Denmark.
authors.affiliation: Research Unit, Mental Health Centre Copenhagen, University of Copenhagen, Copenhagen, Capital Region of Denmark, Denmark; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: annette.Erlangsen@regionh.dk.
authors.forename: Annette
authors.initials: A
authors.lastname: Erlangsen
authors.affiliation: Clinic of Suicide Prevention and Treatment for Adults, Department of Psychiatry, Region of Southern Denmark, Denmark.
authors.forename: Bertel Dam
authors.initials: BD
authors.lastname: Lind
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stuart
authors.affiliation: National Centre for Suicide Research and Prevention, University of Oslo, Oslo, Norway.
authors.forename: Ping
authors.initials: P
authors.lastname: Qin
authors.affiliation: Department of Psychiatry, University of Southern Denmark, Odense, Region of Southern Denmark, Denmark.
authors.forename: Elsebeth
authors.initials: E
authors.lastname: Stenager
authors.affiliation: Department of Child and Adolescent Psychiatry, Clinic of Suicide Prevention and Treatment for Children and Adolescents, Region of Southern Denmark, Denmark.
authors.forename: Kim Juul
authors.initials: KJ
authors.lastname: Larsen
authors.affiliation: Competence Centre for Suicide Prevention, Amager, Capital Region of Denmark, Denmark.
authors.forename: August G
authors.initials: AG
authors.lastname: Wang
authors.affiliation: Competence Centre for Suicide Prevention, Amager, Capital Region of Denmark, Denmark.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hvid
authors.affiliation: Competence Centre for Suicide Prevention, Copenhagen, Capital Region of Denmark, Denmark.
authors.forename: Ann Colleen
authors.initials: AC
authors.lastname: Nielsen
authors.affiliation: Clinic for Suicide Prevention, Aarhus University Hospital Risskov, Aarhus, Central Denmark Region, Denmark.
authors.forename: Christian Møller
authors.initials: CM
authors.lastname: Pedersen
authors.affiliation: Unit for Suicide Prevention, Aalborg University Hospital, North Denmark Region, Denmark.
authors.forename: Jan-Henrik
authors.initials: JH
authors.lastname: Winsløv
authors.affiliation: Clinic for Suicide Prevention, Herning, Central Denmark Region, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Langhoff
authors.affiliation: Clinic for Suicide Prevention, Aarhus University Hospital Risskov, Aarhus, Central Denmark Region, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Mühlmann
authors.affiliation: Research Unit, Mental Health Centre Copenhagen, University of Copenhagen, Copenhagen, Capital Region of Denmark, Denmark.
authors.forename: Merete
authors.initials: M
authors.lastname: Nordentoft
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D000072858:Psychosocial Support Systems; D016728:Self-Injurious Behavior / Q000401:mortality / Q000523:psychology / Q000628:therapy*; D013405:Suicide / Q000523:psychology / Q000706:statistics & numerical data; D055815:Young Adult; D000092864:Suicide Prevention