Differences in incidence of suicide attempts between bipolar I and II disorders and major depressive disorder

Authors

  • K Mikael Holma,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Psychiatry, City of Helsinki Health Centre, Helsinki, Finland
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  • Jari Haukka,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Department of Public Health, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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  • Kirsi Suominen,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Psychiatry, City of Helsinki Health Centre, Helsinki, Finland
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  • Hanna M Valtonen,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Psychiatry, City of Helsinki Health Centre, Helsinki, Finland
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  • Outi Mantere,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Department of Psychiatry, Helsinki University Central Hospital, District of Helsinki and Uusimaa, Helsinki, Finland
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  • Tarja K Melartin,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Department of Psychiatry, Helsinki University Central Hospital, District of Helsinki and Uusimaa, Helsinki, Finland
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  • T Petteri Sokero,

    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
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  • Maria A Oquendo,

    1. Department of Psychiatry, New York State Psychiatric Institute and Columbia University, New York, NY, USA
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  • Erkki T Isometsä

    Corresponding author
    1. Mood, Depression, and Suicidal Behaviour Unit, National Institute for Health and Welfare, Helsinki, Finland
    2. Department of Psychiatry, Helsinki University Central Hospital, District of Helsinki and Uusimaa, Helsinki, Finland
    • Corresponding author:

      Erkki T. Isometsä, M.D., Ph.D.

      Department of Psychiatry

      Institute of Clinical Medicine

      University of Helsinki

      P.O. Box 22 (Välskärinkatu 12 A)

      Helsinki 00014

      Finland

      Fax: +358-9-47163735

      E-mail: erkki.isometsa@hus.fi

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Abstract

Objectives

Whether risk of suicide attempts (SAs) differs between patients with bipolar disorder (BD) and patients with major depressive disorder (MDD) is unclear. We investigated whether cumulative risk differences are due to dissimilarities in time spent in high-risk states, incidence per unit time in high-risk states, or both.

Methods

Incidence rates for SAs during various illness phases, based on prospective life charts, were compared between patients from the Jorvi Bipolar Study (n = 176; 18 months) and the Vantaa Depression Study (n = 249; five years). Risk factors and their interactions with diagnosis were investigated with Cox proportional hazards models.

Results

By 18 months, 19.9% of patients with BD versus 9.5% of patients with MDD had attempted suicide. However, patients with BD spent 4.6% of the time in mixed episodes, and more time in major depressive episodes (MDEs) (35% versus 21%, respectively) and in subthreshold depression (39% versus 31%, respectively) than those with MDD. Compared with full remission, the combined incidence rates of SAs were 5-, 25-, and 65-fold in subthreshold depression, MDEs, and BD mixed states, respectively. Between cohorts, incidence of attempts was not different during comparable symptom states. In Cox models, hazard was elevated during MDEs and subthreshold depression, and among patients with preceding SAs, female patients, those with poor social support, and those aged < 40 years, but was unrelated to BD diagnosis.

Conclusions

The observed higher cumulative incidence of SAs among patients with BD than among those with MDD is mostly due to patients with BD spending more time in high-risk illness phases, not to differences in incidence during these phases, or to bipolarity itself. BD mixed phases contribute to differences involving very high incidence, but short duration. Diminishing the time spent in high-risk phases is crucial for prevention.

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