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.