Risk Factors for Suicidality in Patients With Schizophrenia

A Systematic Review, Meta-analysis, and Meta-regression of 96 Studies

Ryan Michael Cassidy; Fang Yang; Flávio Kapczinski; Ives Cavalcante Passos


Schizophr Bull. 2018;44(4):787-797. 

In This Article

Abstract and Introduction


The lifetime risk of suicide and suicide attempt in patients with schizophrenia are 5% and 25%–50%, respectively. The current meta-analysis aims to determine risk factors associated with suicidality in subjects with schizophrenia. We searched Pubmed, Web of Science, EMBASE, and the reference lists of included studies. Inclusion criteria were met if an article reported a dichotomous sample of patients with schizophrenia with suicidal ideation, attempted suicide, or suicide compared to patients without. We also performed a cohort study meta-analysis as a supplemental analysis. A total of 96 studies with 80488 participants were included in our analysis. Depressive symptoms (P < .0001), Positive and Negative Symptom Scale (PANSS) general score (P < .0001) and number of psychiatric hospitalizations (P < .0001) were higher in patients with suicide ideation. History of alcohol use (P = .0001), family history of psychiatric illness (P < .0001), physical comorbidity (P < .0001), history of depression (P < .0001), family history of suicide (P < .0001), history of drug use (P = .0024), history of tobacco use (P = .0034), being white (P = .0022), and depressive symptoms (P < .0001) were the most consistent variables associated with suicide attempts. The first two were also significant in the cohort meta-analysis. Being male (P = .0005), history of attempted suicide (P < .0001), younger age (P = .0266), higher intelligence quotient (P < .0001), poor adherence to treatment (P < .0001), and hopelessness (P < .0001) were the most consistently associated with suicide. The first three were also significant in the cohort meta-analysis. Our findings may help with future development of preventive strategies to combat suicide. Future studies may combine the above-mentioned variables by using multivariate predictive analysis techniques to objectively stratify suicidality in schizophrenia.


Suicide is the 10th leading cause of death in the United States, with 41149 suicides in 2013 at a rate of 13/100000 persons.[1] A total of 1.3 million individuals older than 18 attempted suicide that same year.[2] The prevalence of schizophrenia is estimated to be around 1% worldwide,[3] and a recent meta-analysis has identified a lifetime risk of suicide of 5% in this population.[4,5] It is also known that 25%–50% of patients with schizophrenia attempt suicide in their lifetime.[6] This represents a 50–100-fold increase in suicidality as compared to general population. However, suicide is a highly preventable event,[7] and there are preventative strategies, such as cognitive behavioral therapy and clozapine, to reduce it in patients with schizophrenia.[8]

Suicide is sometimes viewed as an extreme response to a catastrophic event, such as loss of a close relative. However, many individuals, including patients with schizophrenia, go through these kinds of stressors and yet they do not attempt suicide.[9] Consequently, a growing body of knowledge has put forward several risk factors associated with patients with schizophrenia that attempt suicide.[5,10,11] Particularly, the previous meta-analysis assessed categorical risk factors for suicide in patients with schizophrenia.[12] They analyzed 26 articles and identified 7 categorical risk factors associated with increased suicide risk, which were previous depressive disorders, previous suicide attempts, drug misuse, agitation or motor restlessness, fear of mental disintegration, poor treatment adherence, and recent loss. Since the publication of this meta-analysis in 2005, many large scale studies evaluating schizophrenia have been published internationally. Therefore, in this study, our aim is to provide a systematic review and meta-analysis of both categorical and continuous risk factors for suicidal ideation, suicide attempts, and suicide. We will also explore sources of heterogeneity between studies using meta-regression analysis.