Risk factors for suicide in schizophrenia: Findings from a Swedish population-based case-control study
Introduction
Schizophrenia is a serious mental disorder with life-time prevalence estimates of about 0.4% to 0.5% (Goldner et al., 2002, Saha et al., 2005). Mortality is two- to threefold higher in schizophrenia patients than in the general population (McGrath et al., 2008), suicide being one of the main causes of excess death (Ösby et al., 2000). In recent meta-analyses, the risk of suicide in schizophrenia was found to be 13 times greater than in the general population (Saha et al., 2007), and the life-time risk of suicide in schizophrenia was estimated to be 4.9% (Palmer et al., 2005).
A meta-analysis reported that the suicide risk in schizophrenia is robustly associated with previous depressive disorder, hopelessness, history of suicide attempt, and poor adherence to treatment (Hawton et al., 2005). However, although some studies have also reported that the suicide risk in schizophrenia is associated with male gender (Breier and Astrachan, 1984), higher educational attainment (Drake et al., 1984), substance use disorders (Pompili et al., 2007), and a family history of suicide (De Hert et al., 2001), the findings regarding these and a number of other factors have been inconclusive (Hawton et al., 2005). Moreover, although the suicide risk is known to be greatest early in the time period following the first diagnosis of the disorder (Palmer et al., 2005), data are inconclusive as to how the age at onset of symptoms affects the suicide risk (Hawton et al., 2005). Previous studies in this field have been relatively small, not population-based, and limited by a lack of adjustment for potential confounders. We performed a population-based matched case-control study to assess clinical and demographic risk factors for suicide, selecting as cases 84 consecutive in-patients diagnosed with schizophrenia for the first time in Stockholm County, Sweden, who died from suicide within five years from the index diagnosis, and as controls the same number of living schizophrenia patients from the same population matched by date and age at index diagnosis.
Section snippets
Study subjects
The National Patient Register contains individual-based information on in-patient treatment with complete coverage of psychiatric hospitals in Stockholm County since 1973. For each hospitalization, the register includes the patient's unique civic registration number, dates of admission and discharge, diagnoses at discharge, psychiatric department, and hospital. It is compulsory for all in-patient facilities to submit data on discharge and the register is therefore population-based.
We defined a
Results
Patients who died by suicide (cases) and matched controls were similar regarding the matching criteria (Table 1). Both groups had a mean age of 32.8 (SD 9.7) years and a median age of 29 (range 18–64) years at diagnosis. The suicides occurred between 1987 and 2000 at a mean age of 34.1 years (SD 9.8) and a median age of 31 (range 18–65) years. Suicide by ‘jumping’ and ‘other method’ (including jumping in front of a vehicle) were more frequent than in the general population, while poison was
Discussion
The main findings of this study were that higher educational attainment, age ≥ 30 years at onset of symptoms and a history of a suicide attempt were associated with an increased risk of suicide within five years after a first clinical schizophrenia in-patient diagnosis. There were also tendencies for an increased risk of suicide being associated with having been married or cohabiting, and with a longer total duration of hospitalization. Gender did not significantly affect the suicide risk, nor
Role of the funding source
This study was supported by grants from Stockholm County Council, Gävle County Hospital, Stiftelsen Söderström Königska Sjukhemmet, Psykiatrifonden, and Bror Gadelius stiftelse. Erik Jönsson was supported by the Swedish Research Council (K2007-62X-15078-04-3, K2008-62P-20597-01-3). The funding agencies played no role in the design, data acquisition, analysis, or interpretation of the results.
Contributors
Johan Reutfors, M.D. was responsible for collecting the data; managed the literature review and searches; designed the study protocol; and wrote the first draft of the report. He also participated in the development of the study design, the statistical analyses and the interpretation of data. Lena Brandt, M.Sc. was responsible for the statistical analyses; assisted in the development of the study design, interpretation of data and writing the report. Erik G. Jönsson, M.D., Ph.D. assisted in
Conflict of interest
UÖ has received grant/research support from Bristol-Myers Squibb and Janssen-Cilag; has been a consultant for AstraZeneca, Bristol-Myers Squibb, Ely Lilly, and Pfizer; has been reimbursed by Bristol-Myers Squibb, Ely Lilly, and Pfizer for attending conferences; has received fees for speaking from Bristol-Myers Squibb, Ely Lilly, Organon, and Pfizer. Nothing has been reported by the other authors.
Acknowledgement
We thank Marianne Ask for invaluable assistance in the handling of the clinical records.
References (38)
- et al.
Risk factors for suicide in young people suffering from schizophrenia: a long-term follow-up study
Schizophr Res
(2001) - et al.
Mortality and causes of death in schizophrenia in Stockholm county, Sweden
Schizophr. Res.
(2000) - et al.
Suicide risk in relation to family history of completed suicide and psychiatric disorders: a nested case-control study based on longitudinal registers
Lancet
(2002) - et al.
Effect of barriers on the Clifton suspension bridge, England, on local patterns of suicide: implications for prevention
Br. J. Psychiatry
(2007) - et al.
Characterization of schizophrenic patients who commit suicide
Am. J. Psychiatry
(1984) Suicide in the Western World
- et al.
Risk factors of suicide among schizophrenics
Acta Psychiatr. Scand.
(1990) - et al.
Young cases of schizophrenia identified in a national inpatient register — are the diagnoses valid?
Soc. Psychiatry Psychiatr. Epidemiol.
(2002) - et al.
Suicide among schizophrenics. Who is at risk?
J. Nerv. Ment. Dis.
(1984) - et al.
Evaluation of diagnostic procedures in Swedish patients with schizophrenia and related psychoses
Nord. J. Psychiatry
(2005)
Prevalence and incidence studies of schizophrenic disorders: a systematic review of the literature
Can. J. Psychiatry
Causes and consequences of the gender difference in age at onset of schizophrenia
Schizophr. Bull.
Suicide as an outcome for mental disorders. A meta-analysis
Br. J. Psychiatry
Schizophrenia and suicide: systematic review of risk factors
Br. J. Psychiatry
Suicide and schizophrenia: a nationwide psychological autopsy study on age- and sex-specific clinical characteristics of 92 suicide victims with schizophrenia
Am. J. Psychiatry
Suicide in schizophrenia: findings from a national clinical survey
J. Psychiatr. Pract.
Is the earlier age at onset of schizophrenia in males a confounded finding? Results from a cross-cultural investigation
Br. J. Psychiatry
Suicide among schizophrenic adolescents in the long-term course of illness
Psychopathology
Validity of the diagnosis schizophrenia in a psychiatric inpatient register
Nord. Psykiatr. Tidskr.
Cited by (73)
A systematic review and meta-analysis of suicidality in psychotic disorders: Stratified analyses by psychotic subtypes, clinical setting and geographical region
2022, Neuroscience and Biobehavioral ReviewsA systematic review of suicide and suicide attempts in adolescents with psychotic disorders
2021, Schizophrenia ResearchCitation Excerpt :More recent research suggests a marked increase shortly after diagnosis (Simon et al., 2018) or after the first admission (Kuo et al., 2005; Canal-Rivero et al., 2016). However, in all studies, age of onset is considered the single independent risk factor for suicide, increasing by 1.1% per year (Castelein et al., 2015; Kuo et al., 2005; Reutfors et al., 2009). Consequently, there seems to be general agreement that the greatest time of risk is in the early stages of the disorder.
The processing of angry faces in schizophrenia patients with a history of suicide: An fMRI study examining brain activity and connectivity
2021, Progress in Neuro-Psychopharmacology and Biological Psychiatry