Department of Psychiatry, University of Rochester, New York, USA
University Health Network, Women's Health Program and University of Toronto, Canada
Sunnybrook Health Sciences Centre, Toronto, Canada
Centre for Psychiatry, Barts and the London Queen Mary's School of Medicine and Dentistry, London, UK
University Health Network, Women's Health Program and University of Toronto, Canada
Department of Psychiatry, University of Rochester, New York, USA
Correspondence: Dr Emma Robertson Blackmore, Department of Psychiatry, BOX PSYCH 4-9200, University of Rochester Medical Centre, Rochester, New York 14642-8409, USA. Email: emma_robertsonblackmore{at}urmc.rochester.edu
None. Funding detailed in Acknowledgements.
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Clinical samples have identified a number of psychosocial risk factors for suicidal acts but it is unclear if these findings relate to the general population.
Aims
To describe the prevalence of and psychosocial risk factors for suicidal acts in a general adult population.
Method
Data were obtained from a Canadian epidemiological survey of 36 984 respondents aged 15 years and older (weighted sample n=23 662 430).
Results
Of these respondents, 0.6% (weighted n=130 143) endorsed a 12-month suicidal act. Female gender (OR=4.27, 95% CI 4.05–4.50), being separated (OR=37.88, 95% CI 33.92–42.31) or divorced (OR=7.79, 95% CI 7.22–8.41), being unemployed (OR=1.70, 95% CI 1.50–1.80), experiencing a chronic physical health condition (OR=1.70, 95% CI 1.67–1.86) and experiencing a major depressive episode in the same 12-month period as the act (OR=9.10, 95% CI 8.65–9.59) were significantly associated with a suicidal act.
Conclusions
The psychosocial correlates of suicidal acts in this sample are consistent with those previously reported in clinical and general population samples. These findings reinforce the importance of the determination of suicide risk and its prevention not only of psychiatric illness but of physical and psychosocial factors as well.
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This study seeks to extend our knowledge about suicidal acts in the general population, using data from another population-based survey which sampled the Canadian population aged 15 years and over. We refer to `suicidal acts', as no definition of suicide attempt was provided for respondents and no measure of suicidal intent was available to include in analyses. Our aims were to describe the characteristics of individuals who undertook a suicidal act in the 12 months preceding interview and to examine variables that have been associated with risk for suicide in previous research studies for their association with suicidal acts in this general population sample.
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Sample
The responding sample consisted of 36 984 community-dwelling individuals
aged 15 years or older, with a response rate of 77%; this represents a
weighted population of 23 662 430. In this study respondents were divided into
two groups: those who did and those who did not engage in a suicidal act in
the 12 months preceding the interview. A suicidal act was held to have
occurred if the individual endorsed the statement, `In the last 12 months you
attempted suicide or tried to take your own life'.
Variables
Demographic, social and clinical variables that had previously been
associated with risk of suicide were included in the
analyses.14
Demographic characteristics
Marital status was classified as married, cohabiting, single, separated,
divorced, or widowed. Ethnicity was selected by respondents from pre-defined
categories used by Statistics Canada; for analysis purposes, because of small
cell sizes, this variable was dichotomised into `White' v. `other'.
Education was categorised as less than secondary, secondary graduate, other
post-secondary, or post-secondary school graduate. Respondents characterised
themselves as employed (defined as having worked at a job or business in the
preceding 12 months), unemployed (including those unable to work owing to
illness or disability, and full-time homemakers) or retired; as living in
either an urban or a rural area; and whether they were an immigrant to Canada
(yes/no). Income adequacy was based on the number of people in the household
and the total household income from all sources, and was divided into five
groups ranging from low to high. Definitions of income adequacy (in Canadian
dollars) were as follows:
Psychiatric diagnoses
Psychiatric symptoms were assessed using the World Health Organization
World Mental Health 2000 version of the Composite International Diagnostic
Interview
(WMH–CIDI),15,16
a fully structured and validated interview that generates DSM–IV
diagnoses.17 All
interviews were conducted by trained interviewers using a computer-assisted
application. Most interviews were conducted in person (86%), the remainder by
telephone. Data were available for analyses of lifetime and 12-month diagnoses
of major depressive episode, substance dependence in the past 12 months
(alcohol and/or drug) and select anxiety disorders (lifetime panic disorder
and panic attacks in the past 12 months, and social phobia – lifetime
and 12-month).
Health status
Interviewers enquired about the presence of chronic medical conditions
including arthritis or rheumatism, back problems (excluding fibromyalgia or
arthritis), chronic bronchitis, emphysema or chronic pulmonary disease,
diabetes, thyroid disease, heart disease, cancer, stomach or intestinal
ulcers, bowel disorder or Crohn's disease, epilepsy and stroke. Each condition
was required to have been present for at least 6 months and diagnosed by a
health professional (Table 1).
For the purposes of analysis the variable was dichotomised as the presence or
absence of at least one chronic condition.
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Table 1 Socio-demographic and clinical characteristics of those reporting a
suicidal act occurring in the previous 12 months (unweighted n=222,
weighted n=130 143)
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Respondents were asked, `During the past 12 months have you seen, or talked on the telephone, to a professional about committing suicide or taking your own life?' Respondents were then asked to name all of the professionals they had spoken to from the following list: psychiatrist, family doctor, psychologist, nurse, social worker or counsellor, religious or spiritual advisor such as a priest, chaplain or rabbi, teacher or guidance counsellor, or other.
Social support
Respondents were asked to rate four categories of social support on a
four-point scale ranging from `none of the time' to `all of the time'. These
categories were informational support (the offering of advice, information,
guidance or feedback); tangible support (the provision of material aid or
behavioural assistance); positive social interaction (the availability of
other people to share enjoyable activities, relax with); and affection
(involving expressions of love and affection). A higher score reflects higher
levels of social support.
Religiosity
Respondents were asked to indicate their participation in religious
activities, aside from weddings and funerals, in the preceding year. Five
responses were given ranging from `not at all' to `once a week'. Respondents
were also asked to agree or disagree with the statement, `Spiritual values
play an important role in my life'.
Statistical analysis
To account for survey design effects, the variance used in the calculation
of prevalence estimates, coefficients of variation (standard error of the
estimate) and confidence limits were estimated with the bootstrap technique.
Weighted cross-tabulations were used to estimate the number and proportion of
people who engaged in suicidal acts in the past 12 months. All reported sample
sizes and percentages are weighted. Multivariate logistic regression was used
for analysis; the binary outcome variable was a suicidal act in the preceding
12 months (yes/no). We estimated the association of each demographic and
psychosocial variable with the outcome and all determinants for which the
association was significant at the P<0.01 level were included in a
preliminary multivariate model. The final multivariate logistic regression
model was obtained by removing variables one at a time until all remaining
variables were significant at the P<0.01 level. All analyses were
performed using the Statistical Package for the Social Sciences version 13.0
for Windows. Odds ratios and 95% confidence intervals are presented for the
main findings.
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The demographic, clinical and psychosocial characteristics of the respondents who reported a suicidal act in the 12 months preceding the interview are shown in Table 1. In comparison with the rest of the sample, these respondents were predominantly female, were less likely to be married or cohabiting, were younger, had a lower level of education, and a high proportion were unemployed. More than three-quarters of these respondents (77%) reported having one or more chronic health conditions. Almost two-thirds met lifetime criteria for a major depressive episode, with more than half meeting criteria for one or more episodes in the same 12-month period as the suicidal act. Rates of anxiety disorders and substance dependence were considerably lower. Almost half indicated that religion and spiritual values had an important role in their lives.
The associations between psychosocial and clinical variables and risk of 12-month suicidal act expressed as adjusted odds ratios are shown in Table 2. All variables are significant at the P<0.01 level. Younger age, female gender, unemployment and income inadequacy were associated with having made a suicidal act in the past 12 months. Education level revealed an inconsistent pattern. A previous major depressive episode was a significant correlate of suicide act status, as were substance dependence and one or more chronic medical conditions in the past 12 months. Suicidal acts were significantly associated with higher levels of tangible social support. Respondents who rated themselves as being less religious were more likely to report a suicidal act than those who participated in religious activities weekly. However, the odds of a suicidal act were considerably higher among those who participated intermittently than among those who never participated in religious activities.
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Table 2 Demographic, clinical and psychosocial correlates of 12-month suicidal
act
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Psychosocial correlates of suicidal acts
In addition to the demographic characteristics of female
gender,9 younger
age18 and White
ethnicity,5 a number
of correlates for suicidal acts and attempts have been identified from studies
of clinical samples. These include being separated or divorced, having a lower
level of education, poverty, unemployment and social
isolation,5,9
and physical
illness.19
Religious beliefs and participation in religious activity are thought to be
protective against suicidal
behaviour.20,21
In our study the psychosocial correlates of suicidal acts in this general
adult population are consistent with those reported previously, namely female
gender,9 being
separated or
divorced,4,5,18
younger
age,4,18
lower level of
education,4,5
and being
unemployed.4,5,9
Although ecological studies have long demonstrated associations between income
and suicide,22 we
are not aware of previous population-based survey data having confirmed this
link. Probable relationships between perceived income adequacy and depression,
substance dependence, physical illness burden and other unmeasured factors
should be considered, however, and the finding interpreted with caution. It
should also be noted that given the cross-sectional nature of the data, it is
not possible to comment on the temporal ordering of events. Therefore, one
cannot distinguish between whether the suicidal act, or the psychiatric
symptoms linked with it, led to or were a consequence of psychosocial
adversity.23
Physical conditions
Using National Comorbidity Survey (NCS) data from 1990–2, Goodwin
et al found that even after controlling for socio-demographic
variables, mental disorder diagnosis and regular physical activity, there were
significantly increased odds of lifetime suicide attempt associated with
having AIDS, lung disease or
ulcers.24 Further,
there was a linear association between the likelihood of suicide attempt and
the total number of physical illnesses. These authors' findings were
consistent with previous studies of physical illness and completed
suicide,8 an issue
particularly pertinent to older
adults.25 Our
observation of increased odds for suicidal acts within the past 12 months and
having one or more chronic medical conditions in that same time frame
reinforces the need to consider primary and specialty medical practice as a
venue for suicide risk assessment and
prevention.26
Psychiatric conditions
Most individuals who complete or attempt suicide have a diagnosable
psychiatric illness; Kessler et al reported that 88–89% of
suicide attempters met criteria for one or more 12-month DSM
disorders.4
Depressive disorders are most often
diagnosed.7,8
This data-set allowed us to examine fewer psychiatric disorders than
Kessler et
al;5
nevertheless, the nine times greater odds of suicidal act among respondents
with a major depressive episode that we observed is similar to the strength of
the association they reported (OR=11). In contrast, the presence of a
substance dependence diagnosis, social phobia or panic attacks in the past 12
months did not increase the odds of an act in that same time frame in the
Canadian sample, whereas substance use disorders and anxiety disorders
(including social phobia and panic disorder) were significant predictors in
the NCS, albeit at considerably lower odds ratios than for major depression.
Vigilance for mood disorders in health settings and routine screening for
suicidal ideation and intent when depression is present are warranted.
Although similar caution is indicated for suicide among patients with other
psychiatric diagnoses, additional study is needed to translate the
implications of population-based observations to health policy.
The finding that increased levels of tangible support were associated with increased risk of suicidal act appears contradictory at first. Although we cannot comment on the temporal relationship between the suicide act and the other factors studied, this finding may reflect that individuals received increased practical support following the act.
Religious beliefs
Previous research suggests that religious beliefs and participation in
religious activities protect against
suicide.20,21,27
Consistent with these reports, we found a linear relationship between
self-perceived religiosity and the odds of a suicidal act in the past 12
months. The relationship with participation in religious activities was less
straightforward. Weekly participants were clearly at lowest risk, underscoring
the protective effect of religious engagement. We also observed, however, that
those who never participated in religious activities were at less risk of
suicidal acts than individuals who did so three or four times a year, and
those who participated monthly and once a year were at intermediate risk. The
means by which frequent and regular religious participation protects from
suicide remains obscure. Postulated mechanisms include a broader social
network and increased instrumental support that may result from frequent
participation.20
Alternatively, if frequent participation is linked to closer adherence to a
religious doctrine that strongly proscribes suicide (as does, for example, the
Catholic church), these individuals might be less likely to harm
themselves.20 The
greater risk associated with intermediate or irregular participation than none
is more difficult to explain. This pattern could result if irregular
participation were an indicator of ambivalent religiosity, an episodic
response to crises in one's life, or a means of managing ongoing stress.
Greater attention should be given to opportunities for detection and
prevention of suicide through programming based in the faith community.
Study limitations
This study is subject to a number of limitations. First, we refer here to
`suicidal acts' as no definition of suicide attempt was provided for
respondents and no measure of suicidal intent was available to include in
analyses. Consequently, suicidal ideation and self-harming behaviours without
intent to die might have been endorsed by some respondents and included as
suicidal acts. Such misclassification would inflate the rates reported here.
Evidence suggests that those who injure with intent to die differ
significantly from ideators and those who act without lethal intent; they
engage in more serious self-injury, and are more likely to die subsequently by
suicide.28 Our
findings, therefore, should be interpreted with caution.
Because of the construction of the survey, we were unable to determine whether participants who reported no suicidal act in the past 12 months had one or more suicidal acts earlier in life. Nor could we establish the number of suicidal acts in those who did endorse one or more in the past 12 months, or examine their level of lethality of implementation or intent. Repeat suicidal acts and acts with high potential lethality may have different implications for risk assessment and prevention.29,30 Subsequent population-based surveys should include measures that allow more refined analyses of subgroups of suicidal people. The data are based on self-disclosure from respondents and may be an under-representation of suicidal acts. However, the fact that identical 12-month prevalence figures were reported from the NCS in the USA4 and by Paykel et al in the UK11 lend confidence, at least, to the reliability of the findings. Respondent bias may influence reporting of psychiatric symptoms such as depression, which in turn might influence reporting of physical conditions, income adequacy, social support and spirituality. Although the sample is representative of the Canadian population aged over 15 years, the number who endorsed suicidal acts was insufficient to allow examination of subgroups (categorised for example by gender, age, ethnicity, reason for unemployment or urban/rural residence) without threatening to compromise respondent anonymity. Neither could the sample size support modelling of potentially important interactions between correlates. Future studies should include even larger samples to enable more fine-grained analyses of putative risk factors, and their interactions, in specific segments of the population.
The interviews were conducted by lay interviewers and not clinicians. Therefore, it was not possible to distinguish between affective disorders due to the direct physiological effects of a substance (e.g. illicit drugs or medication and those due to a general medical condition). For that reason, we refer only to `major depressive episode' rather than major depressive disorder.
Implications of the study
Suicide and suicidal acts are a major cause of morbidity and mortality
throughout the world. Strategies that target the detection and treatment of
individuals at high risk of suicidal behaviour are an essential element of any
comprehensive prevention strategy. Strategies that target high-risk
populations alone are
insufficient;31
they must be complemented by population-based strategies that target
vulnerable individuals and groups prior to the development of suicidal crises
and entry into the clinical care system – or death. Survey data from
representative samples of the general population yield information that is
essential to the design and ongoing evaluation of those strategies. Consistent
with findings from the NCS, this study reinforces the importance to the
determination of suicide risk and its prevention not only of psychiatric
illness, but of physical and psychosocial factors as well.
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