Completed and attempted suicides among 18,154 subjects with schizophrenia included in a large simple trial

To characterize subgroups of subjects with schizophrenia from the Ziprasidone Observational Study of Cardiac Outcomes (ZODIAC) trial who either completed or attempted suicide and those who did not.

The ZODIAC, conducted between February 2002 and March 2007, was an open-label, randomized, large simple trial of patients with schizophrenia (N = 18,154) followed up for 1 year by unblinded investigators providing usual care in 18 countries; the primary outcome measure was nonsuicide mortality. Every report on a completed or attempted suicide was independently adjudicated using a predefined algorithm. Primary analysis for the current report examined the association between completed or attempted suicides and the baseline variables using descriptive statistics and multivariate logistic regression models. Usage of "hard" or "soft" methods for attempted or completed suicide and distribution of suicide-related events by geographical region were also summarized.

Overall incidences of subjects who either completed (35/18,154) or attempted (108/18,154) suicide were low, as were rates per person-time on assigned treatment analysis (0.24 for completed and 0.74 for attempted suicides per 100 person-years of exposure). The highest suicide-related mortality was seen among subjects recently diagnosed with schizophrenia. Among all potential baseline risk factors for completed suicide examined, the variables most associated with completed suicide were history of suicide attempts (OR = 2.6; 95% CI, 1.33-5.12) and usage of antidepressant medication (OR = 3.5; 95% CI, 0.84-14.85). History of > 5 hospitalizations in the past (OR = 2.1; 95% CI, 1.35-3.31) and history of suicide attempts (OR = 5.0; 95% CI, 3.21-7.76) were the variables most associated with attempted suicide among potential baseline risk factors for suicide attempts.

Our results, obtained in a large prospective randomized study, confirm current clinical understanding regarding completed or attempted suicide in schizophrenia and the associated risk factors.

ClinicalTrials.gov identifier: NCT00418171.