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Genetic risk of suicidal behavior in bipolar spectrum disorder: analysis of 737 pedigrees

Authors

Errata

This article is corrected by:

  1. Errata: Corrigendum Volume 16, Issue 2, e1, Article first published online: 5 March 2014

Corresponding author:

Martin Alda, MD, FRCPC

Department of Psychiatry

Dalhousie University

5909 Veterans' Memorial Lane

Abbie J. Lane Building, Room 3088

Halifax

Nova Scotia B3H 2E2

Canada

Fax: +1-902-473-4877

E-mail: malda@dal.ca

Abstract

Objectives

Suicide is a significant cause of mortality in patients with major affective disorders (MAD), and suicidal behavior and MAD co-aggregate in families. However, the transmission of suicidal behavior is partially independent from that of MAD. We analyzed the lifetime prevalence of completed and attempted suicides in a large sample of families with bipolar disorder (BD), its relation to family history of MAD and BD, and the contribution of clinical and treatment factors to the risk of suicidal behavior.

Methods

We studied 737 families of probands with MAD with 4919 first-degree relatives (818 affected, 3948 unaffected, and 153 subjects with no information available). Lifetime psychiatric diagnoses and suicidal behavior in first-degree relatives were assessed using semi-structured interviews, family history methods, and reviews of clinical records. Cox proportional hazard and logistic regression models were used to investigate the role of clinical covariates in the risk of suicidal behavior, and in the prevalence of MAD and BD.

Results

The estimated lifetime prevalence of suicidal behavior (attempted and completed suicides) in 737 probands was 38.4 ± 3.0%. Lithium treatment decreased suicide risk in probands (p = 0.007). In first-degree relatives, a family history of suicidal behavior contributed significantly to the joint risk of MAD and suicidal behavior (p = 0.0006).

Conclusions

The liability to suicidal behavior is influenced by genetic factors (particularly family history of suicidal behavior and MAD). Even in the presence of high genetic risk for suicidal behavior, lithium treatment decreases suicide rates significantly.

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