Objective: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.Method: 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.
Results: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.
Conclusions: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.
Suicide is a major cause of death among patients with schizophrenia, 1 with lifetime prevalence estimates over 10 times higher than the general population 2 and a relatively higher suicide risk found in younger age groups of patients.3,4 The risk is particularly high in the first episode of the illness and decreases with time after the first hospital admission. 5 Different studies, using different populations and methods, have yielded varying estimates of the suicide rate in schizophrenia. 6,7 While earlier research has suggested that up to 13% of patients with schizophrenia commit suicide, 2 more recent studies that take into account the variable suicide risk during the life span (a higher risk close to illness onset and thereafter a declining risk) have reported a lifetime suicide mortality of 4%-5%. 6-9 Nevertheless, this figure remains significantly higher than estimates for the general population, with the mortality gap between the 2 populations increasing over the la...