Repetition risk for adolescent self-poisoning: a multiple event survival analysis

Authors

  • David Martin Reith,

    Corresponding author
      David Martin Reith, Senior Lecturer
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  • Ian Whyte,

    1. David Martin Reith, Senior Lecturer
      Discipline of Paediatrics, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand. Email: david.reith@stonebow.otago.ac.nz

      Ian Whyte, Associate Professor
      School of Population Health Sciences, Faculty of Health, University of Newcastle, Newcastle, Australia

      Greg Carter, Senior Lecturer
      Discipline of Psychiatry, University of Newcastle, Newcastle, Australia
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  • Greg Carter

    1. David Martin Reith, Senior Lecturer
      Discipline of Paediatrics, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand. Email: david.reith@stonebow.otago.ac.nz

      Ian Whyte, Associate Professor
      School of Population Health Sciences, Faculty of Health, University of Newcastle, Newcastle, Australia

      Greg Carter, Senior Lecturer
      Discipline of Psychiatry, University of Newcastle, Newcastle, Australia
    Search for more papers by this author

David Martin Reith, Senior Lecturer

Abstract

Objectives: To examine risk factors associated with re-presentation (event rates) following an initial episode of hospital treated self-poisoning.

Method: A longitudinal cohort study using the Hunter Area Toxicology Service (HATS) database of all presentations to hospital of self-poisoned patients aged 10−19 in Newcastle and Lake Macquarie Regions of New South Wales from January 1991 to December 1995. The study factors were: age, gender, employment status, ‘substance abuse’ and psychiatric diagnosis at index (first documented episode during the study time-period) admission. The main outcome measure was re-presentations per unit time. Time-event analysis (multivariate) was used to compare re-presentation rates per person-year exposure to the study factors.

Results: There were 450 patients who presented on a total of 551 occasions. The median and modal age at initial presentation was 17. Three hundred and nine (69%) were female and 141 (31%) were male. The probability (95% CI) of a patient re-presenting within one year of an index admission with self poisoning was 0.09 (0.07−0.12) and within 5 years was 0.16 (0.12−0.21). The adjusted rate ratios for episodes of re-presentation were: any ‘substance abuse (ever)’ 3.87 (2.08−7.21), ‘alcohol abuse’ 2.32 (1.15−4.68),‘benzodiazepine abuse’ 4.89 (1.63−14.62), schizophrenia and other psychotic disorders (DSM-IV) 2.85 (1.2−6.79), and any personality disorder (DSM-IV) 2.68 (1.73−4.16).

Conclusions: Interventions to decrease recurrence rates for adolescent self poisoning should be directed towards substance (particularly alcohol or benzodiazepine) abuse, non-affective psychoses and personality disorder.

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