Predictors of suicide at time of diagnosis in schizophrenia spectrum disorder: A 20-year total population study in Ontario, Canada

Background: Suicide is a major cause of mortality for individuals with schizophrenia spectrum disorders (SSD). Understanding the risk factors for suicide at time of diagnosis can aid clinicians in identifying people at risk. Methods: Records from linked administrative health databases in Ontario, Canada were used to identify individuals aged 16 through 45 years who received a first lifetime diagnosis of SSD (schizophrenia, schizoaffective disorder, psychotic disorder not otherwise specified (NOS)) using a validated algorithm between 01/01/1993 and 12/31/2010. The main outcome was death by suicide following cohort entry until 12/31/2012. Outcomes: 75,989 individuals with a first SSD diagnosis (60.1% male, 39.9% female) were followed for an average of 9.56 years. During this period, 1.71% of the total sample (72.1% male, 27.9% female) died by suicide, after an average of 4.32 years. Predictors of suicide death included male sex (HR 2.00, 95% CI 1.76-2.27), age at diagnosis between 26 and 35 (HR 1.27, 95% CI 1.10-1.45) or 36-45 (HR 1.34, 95% CI 1.16-1.54), relative to 16-25, and suicide attempt (HR 2.23, 95% CI 1.86-2.66), drug use disorder (HR 1.21, 95% CI 1.04-1.41), mood disorder diagnosis (HR 1.32, 95% CI 1.17-1.50), or mental health hospitalization (HR 1.30 95% CI 1.13-1.49) in the 2 years prior to SSD diagnosis. Interpretation: Death by suicide occurs in 1 out of every 58 individuals and occurred early following first diagnosis of SSD. Psychiatric hospitalizations, mood disorder diagnoses, suicide attempts prior to SSD diagnosis, as well as a later age at first diagnosis, are all predictors of suicide and should be integrated into clinical assessment of suicide risk in this population. (c) 2020 Elsevier B.V. All rights reserved.