Psychological Medicine

Original Article

A risk index for 12-month suicide attempts in the National Comorbidity Survey Replication (NCS-R) 1

a1 National Institute of Psychiatry and Universidad Autonoma Metropolitana, Mexico City, Mexico
a2 Zurich University Psychiatric Hospital, Zurich, Switzerland
a3 Department of Psychology, Harvard University, Cambridge, MA, USA
a4 Department of Health Care Policy, Harvard Medical School, Boston, MA, USA

Article author query
borges g   [PubMed][Google Scholar] 
angst j   [PubMed][Google Scholar] 
nock mk   [PubMed][Google Scholar] 
ruscio am   [PubMed][Google Scholar] 
walters ee   [PubMed][Google Scholar] 
kessler rc   [PubMed][Google Scholar] 


Background. Clinical judgments about the likelihood of suicide attempt would be aided by an index of risk factors that could be quickly assessed in diverse settings. We sought to develop such a risk index for 12-month suicide attempts among suicide ideators.

Method. The National Comorbidity Survey Replication (NCS-R), a household survey of adults aged 18+, assessed the 12-month occurrence of suicide ideation, plans and attempts in a subsample of 5692 respondents. Retrospectively assessed correlates include history of prior suicidality, sociodemographics, parental psychopathology and 12-month DSM-IV disorders.

Results. Twelve-month prevalence estimates of suicide ideation, plans and attempts are 2·6, 0·7 and 0·4% respectively. Although ideators with a plan are more likely to make an attempt (31·9%) than those without a plan (9·6%), 43% of attempts were described as unplanned. History of prior attempts is the strongest correlate of 12-month attempts. Other significant correlates include shorter duration of ideation, presence of a suicide plan, and several sociodemographic and parental psychopathology variables. Twelve-month disorders are not powerful correlates. A four-category summary index of correlates is strongly related to attempts among ideators [area under the receiver operator characteristic curve (AUC)=0·88]. The distribution (conditional probability of attempt) of the risk index is: 19·0% very low (0·0%), 51·1% low (3·5%), 16·2% intermediate (21·3%), and 13·7% high (78·1%). Two-thirds (67·1%) of attempts were made by ideators in the high-risk category.

Conclusions. A short, preliminary risk index based on retrospectively reported responses to fully structured questions is strongly correlated with 12-month suicide attempts among ideators, with a high concentration of attempts among high-risk ideators.

(Published Online August 29 2006)

c1 Department of Health Care Policy, Harvard Medical School, 180 Longwood Avenue, Boston, MA 02115, USA. (Email:


1 The views and opinions expressed in this report are those of the authors and should not be construed to represent the views of any of the sponsoring organizations, agencies, or the US Government.