Individual and parental determinants

Characteristics of index subjects include the repetition of suicide attempt hospitalizations, mental (diagnosis-specific) and somatic inpatient care, and socio-demographics (i.e., country of birth, area or residence, sex, age, educational level).

The following classification was used with regard to diagnosis-specific mental disorders: Schizophrenia and non-affective psychoses (F20-F29); affective disorders (F30-39); substance abuse disorders (F10-F19); neurotic, stress-related and somatoform disorders (F40-F48); organic disorders including mental retardation (F00-F09, F70-79); behavioural, emotional and developmental disorders (F50-59, F61-F69, F80-F89, F90-F99); personality disorders (F60) (Table 1).

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Table 1. Descriptive statistics of individuals with inpatient care due to suicide attempt (1994–96).

https://doi.org/10.1371/journal.pone.0146130.t001

Parental characteristics included parental disability pension, mental and somatic inpatient care, suicide attempt, suicide, death other than suicide, as well as parental educational level (Table 1). Paternal or maternal education, whichever was highest was used, in accordance with previous studies [13]. For suicide, events of determined and undetermined intent were combined in the same way as for suicide attempts (see above).

All individual variables and parental markers were measured from the start of the respective register (see previous paragraph) up until the year before the index event for individuals with suicide attempt.

The socio-demographic characteristics (age, sex) of index persons and parents were measured on December 31st 1994.

Outcome measures

Three different outcome measures were analysed: 1) disability pension, 2) long-term sickness absence (more than 90 registered days with sickness absence during one calendar year), and 3) long-term unemployment (more than 180 registered days with unemployment benefits during one calendar year).

All residents with a permanently reduced work capacity due to injury or disease can be granted permanent disability pension. Since 2003, temporary disability pension (“aktivitetsersättning”) can be granted for young individuals between 19 and 29 years of age in case of reduced work capacity or in case that compulsory education is not completed at 19 years [7]. Sick pay is paid by the respective employer for the first 2 weeks, and there is one qualifying day (more for self-employed) without benefits. It is generally granted temporarily. After seven days of self-certification, a physician certificate is required. Sickness absence amounts to a capped 80% of lost income, disability pension to approximately 65%.

All individuals who live in Sweden, aged over 16 years and have an income from work or unemployment benefits are eligible for sickness benefits by the Social Insurance Agency if they have a reduced work capacity due to disease or injuries.

In order to be eligible for unemployment benefits, the individual needs to be unemployed, able to work, and ready to accept work that is offered. In addition, prior to becoming unemployed the applicant shall have worked at least six months [21]. The data used here cover benefits paid by the Social Insurance Agency [7].

Statistical methods

For all individual and parental determinants, missing values were coded as a separate category and included in the analysis. Cox regression with time dependent covariates was used in order to adjust for changes in individual risk factors during follow-up. Time dependent covariates measured during follow-up included suicide attempt, inpatient care due to mental/somatic diagnoses and inclusion in the labour market (as indicated by a minimum annual salary). The following additional time-dependent variables during follow-up were considered for specific outcomes as reported in brackets: long-term unemployment/year (disability pension, long-term sickness absence) and long-term sickness absence (unemployment). All time-dependent covariates were dichotomized and measured annually.

Follow up lasted for as long as 16 years (1995–2010). Censoring was due to emigration to a foreign country, death, or end of follow up, whichever occurred first. In the analyses of unemployment and sickness absence as outcome measures, censoring was also due to disability pension because individuals with disability pension are not eligible for unemployment or sickness absence benefits.

Interaction of sex with the other risk factors was tested with the partial likelihood ratio test. If there was a significant interaction effect (p<0.05), analyses were stratified by sex.

Ethical statement

Ethical approval for this study was obtained from the Regional Ethical Review Board, Karolinska Institutet, Stockholm (review number 2007/762-31). The ethical review board approved the study and waived the requirement that informed consent of research subjects should be obtained. The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008.

Disability pension

In the crude analyses, granting of disability pension was positively associated with older age (>20 years, HR 2.3, 95% CI: 2.0, 2.6), negatively associated with country of birth outside the European Union (HR 0.5, 95% CI: 0.4, 0.7), and the hazard ratio increased with number of suicide attempts reaching a three-fold HR for individuals with three or more attempts. Suicide attempters with previous psychiatric inpatient care had increased risk for disability pension, with HRs being highest for schizophrenia (HR 7.2, 95% CI: 5.6, 9.3), followed by personality disorders (HR 5.2, 95% CI: 4.1, 6.5). Earlier somatic inpatient care was associated with an HR of 1.7 (95% CI: 1.5, 1.9). Among the parental characteristics, low educational level (HR 1.2, 95% CI: 1.0, 1.4), psychiatric inpatient care (HR 1.4, 95% CI: 1.3, 1.6), disability pension (HR 1.6, 95% CI: 1.5, 1.8), and parental non-suicidal death (HR 1.4, 95% CI: 1.2, 1.6) were associated with a higher risk for disability pension in offspring (Table 2).

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Table 2. Crude hazard ratios (HR) and 95% confidence intervals (CI) for the risk of unemployment (>180 days), sickness absence (>90 days), and disability pension in 1995–2010 in young suicide attempters in 1992–94.

https://doi.org/10.1371/journal.pone.0146130.t002

In the fully adjusted model, female sex (HR 1.2, 95% CI: 1.1, 1.3), older age (HR 1.9, 95% CI: 1.9, 2.5) and low educational level (HR 1.5, 95% CI: 1.2, 1.9) remained positively associated with subsequent disability pension, while country of birth outside the European Union decreased the relative risk of disability pension (HR 0.6, 95% CI: 0.4, 0.8).

Repeated suicide attempts were associated with a higher risk of disability pension (3 or more attempts: HR 1.6, 95% CI: 1.4, 1.9). Schizophrenia (HR 5.4, 95% CI: 4.2, 7.0) and personality disorders (HR 3.9, 95% CI: 3.1, 4.9) remained the diagnoses with the largest risk estimates related to disability pension. Earlier somatic inpatient care (HR 1.2, 95% CI: 1.1, 1.4) and parental disability pension (HR 1.4, 95% CI: 1.2, 1.5) were also significantly associated with disability pension (Table 3).

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Table 3. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the risk of unemployment (>180 days), sickness absence (>90 days), and disability pension in 1995–2010 in relation young suicide attempters in 1992–94.

https://doi.org/10.1371/journal.pone.0146130.t003

Sickness absence ≥90 days

In the crude analyses, long-term sickness absence was positively associated with female sex (HR 1.4, 95% CI: 1.3, 1.6) and older age (>20 years, HR 1.8, 95% CI: 1.6, 1.9), and negatively associated with country of birth in the European Union but outside of Scandinavia (HR 0.6, 95% CI: 0.4, 0.9). The hazard ratio increased in a dose-response pattern with number of suicide attempts, reaching a 1.5-fold HR for individuals with three or more attempts (HR 95% CI: 1.3, 1.7). Most psychiatric diagnostic groups of individuals with previous psychiatric inpatient care had increased HR for long-term sickness absence, with HRs being highest for affective disorders (HR 1.4, 95% CI: 1.2, 1.7), followed by developmental disorders (HR 1.2, 95% CI: 1.1, 1.4). Earlier somatic inpatient care was associated with a HR of 1.5 (95% CI: 1.3, 1.6). Among the parental characteristics, low educational level (HR 1.4, 95% CI: 1.2, 1.5), psychiatric inpatient care (HR 1.1, 95% CI: 1.1, 1.2), disability pension (HR 1.3, 95% CI: 1.2, 1.4), and parental non-suicidal death (HR 1.2, 95% CI: 1.0, 1.3) were all associated with a higher risk for sickness absence in offspring (Table 2).

In the fully adjusted model, female sex (HR 1.6, 95% CI: 1.4, 1.7), older age (HR 1.7, 95% CI: 1.5, 1.9) and residence in small cities or villages (HR 1.1, 95% CI: 1.0, 1.2) were positively associated with subsequent sickness absence. Repeated suicide attempts were associated with a higher risk (three or more attempts: HR 1.2, 95% CI: 1.1, 1.3), and there was no additional risk from previous psychiatric diagnoses on the risk of long-term sickness absence. Earlier somatic inpatient care (HR 1.3, 95% CI: 1.2, 1.4) and parental disability pension (HR 1.1, 95% CI: 1.0, 1.2) had some effect on long-term sickness absence in offspring, and sickness absence was also associated with parental education, with a 1.2-fold risk (95% CI: 1.1, 1.4) for offspring of parents with low educational level (Table 3).

An interaction with sex and repetitive suicide attempts was found with regard to subsequent sickness absence. Men with two and more than two suicide attempts had higher HRs (1.4 (1.2–1.7); 1. 5 (1.1–1.9) for subsequent sickness absence, respectively. Related estimates for women were 1.1 (1.0–1.3) and 1.1 (1.0–1.3).

There was an additional interaction with sex and previous mental diagnosis-specific inpatient care with regard to subsequent sickness absence. Men had generally higher HRs than women. For example, the HRs and CIs for inpatient care due to substance abuse and behavioural disorders for males were 1.2 (1.0–1.5) and 1.4 (1.0–2.1), respectively. The corresponding estimates among females were 0.9 (0.8–1.1) and 1.1 (0.9–1.3), respectively.

Unemployment ≥180 days

In the crude analyses, long-term unemployment was negatively associated with female sex (HR 0.8, 95% CI: 0.7, 0.8), and positively associated with older age (>20 years, HR 1.4, 95% CI: 1.3, 1.5), residence in villages (HR 1.2, 95% CI: 1.0, 1.3) or medium-sized cities (HR 1.2, 95% CI: 1.1, 1.3), country of birth outside of the European Union (HR 1.4, 95% CI: 1.2, 1.6), and low educational level (HR 1.8 95% CI: 1.4, 2.2). Among previous psychiatric medical diagnostic groups, only a diagnosis of substance abuse (HR 1.2, 95% CI: 1.0, 1.3) was significantly associated with long-term unemployment. Earlier somatic inpatient care (HR 1.1, 95% CI: 1.0, 1.2), and parental characteristics including low educational level (HR 1.3, 95% CI: 1.2, 1.5), psychiatric inpatient care (HR 1.3, 95% CI: 1.1, 1.4), disability pension (HR 1.2, 95% CI: 1.1, 1.3) and non-suicidal death (HR 1.2, 95% CI: 1.0, 1.4) were also associated with long-term unemployment in the crude analyses (Table 2).

In the adjusted model, female sex was negatively associated with subsequent long-term unemployment (HR 0.8, 95% CI: 0.7, 0.9). Residence in villages (HR 1.2, 95% CI: 1.1, 1.3) or medium-sized cities (HR 1.1, 95% CI: 1.0, 1.2), country of birth outside the European Union (HR 1.5, 95% CI: 1.3, 1.8) and low (HR 1.8, 95% CI: 1.4, 2.2) or medium educational level (HR 1.7, 95% CI: 1.4, 2.2) remained significant predictors of subsequent long-term unemployment. Also low (HR 1.2, 95% CI: 1.1, 1.3) or medium (HR 1.1, 95% CI: 1.0, 1.3) parental educational level, and parental psychiatric inpatient care (HR 1.2, 95% CI: 1.1, 1.4) remained associated with later long-term unemployment (Table 3).

Main findings

We examined the association between various medical, socio-demographic, and parental risk factors among persons who had inpatient care due to suicide attempt with subsequent labour market marginalization, which was defined as long-term unemployment, long-term sickness absence or granting of disability pension. Medical risk factors were most important for the subsequent granting of disability pension and also for long-term sickness absence. With regard to long-term unemployment, medical risk factors were of marginal importance. In contrast, all socio-demographic factors were associated with higher risk for unemployment. This included male sex and non-European migrant status. On the other hand, male sex and birth outside Europe were associated with decreased risk of being granted disability pension. Interaction tests revealed that men with previously diagnosed mental disorders or repeated attempts had higher risk of long-term sickness absence than women.

This study revealed clear variation in the relevance of socio-demographic and medical risk factors for various markers of labour market marginalization. We found that repeated suicide attempts and somatic comorbidity in young suicide attempters were predictive for subsequent sickness absence and disability pension but not for unemployment. Previous inpatient care due to mental disorders was only predictive of subsequent disability pension. Consistent with earlier studies, schizophrenia and personality disorders were most strongly associated with disability pension [15,22]. Potential explanations include that the medical severity of the underlying mental disorder, repetitive attempts and somatic comorbidity are likely to have a stronger effect on outcomes which are based upon a medical assessment (sickness absence, disability pension) as compared to other outcomes independent from assessments such as unemployment. Still, another potential explanation for the lower relevance of medical factors in long-term unemployment may be due to a selection of healthier individuals into the group at risk for unemployment. The healthy worker effect suggests that individuals who are sicker are less likely to enter the labour market [23], and more likely to leave it prematurely e.g. due to disability pension or death. The sicker individuals may therefore be less likely to be at risk for unemployment and a competing risk scenario may be present.

Being born in a country outside Europe was associated with decreased risk of disability pension but increased risk for unemployment. This finding may signal that immigrants with suicide attempts who were born outside Europe enter a labour market marginalization track that typically involves long-term unemployment, but not granting of disability pension. In contrast to this finding, previous studies reported an increased risk of disability pension for immigrants from outside the EU who experienced sickness absence due to stress-related mental disorders or depressive episodes [24,25]. Beside the fact that our study population was defined differently as individuals with suicide attempt, the study population in our study was also younger and follow-up was considerably longer. Potential social and cultural differences in the access to healthcare, treatment, evaluation of a disability pension or in the process of a granting disability pensions for suicide attempters with different ethnic and cultural background might be alternative explanations for this finding [26,27]. Future studies are warranted to elucidate mechanisms behind the lower risk of disability pension and the higher risk of unemployment among non-European migrants with suicide attempt.

Lower socio-economic status and older age was predictive for all outcome measures, though to varying degrees. This is in line with previous findings, that labour market marginalization is socially determined [28,29]. Living in rural areas was predictive of sickness absence and unemployment. Similar findings were reported in sickness absentees due to stress-related mental disorder and outpatients due to depressive episode with regard to higher relative risk of subsequent disability pension [24,25]. Regional differences in access to the labour market and health care as well as differences in rehabilitation options in rural areas might explain this finding.

Women had higher risk of being granted disability pension or long-term sickness absence, whereas men had a higher relative risk for long-term unemployment which is in line with previous studies in individuals with sickness absence or outpatient care due to mental disorders [25]. Men had a higher risk for sickness absences in case of repetitive suicide attempts and previous inpatient care due to mental disorders than women. Potential explanations for these gender differences include the lower help-seeking behaviour among men [30], resulting in under diagnosis and under treatment of mental disorders. Both inpatient care due to mental disorders and repetitive suicide attempts were considerably more prevalent among women compared to men. Men with inpatient care due to mental disorders or repetitive suicide attempts may therefore be characterised by a higher medical severity as compared to women.

In contrast, parental disability pension was associated with a higher risk of disability pension and long-term sickness absence in offspring suicide attempters. Both intra-familial morbidity and social patterns that may influence granting of disability pension may play a role in this finding. A recent study identified low labour market participation in the parents as risk factors for sickness absence in the offspring [31]. Parental inpatient care due to mental disorders was the only parental factor associated with an increased risk of long-term unemployment. Parental psychiatric morbidity could be viewed as a medical risk factor or a marker of psychosocial adversity during childhood, including but not limited to less beneficial child rearing styles and less stable parent-child relationships [19].

Strengths and limitations

Strengths of the present study include its prospective design and the use of national register data which have practically no dropout rate. Evaluations of several registers have shown high data quality. For example, 1.2% and 0.8% missing main diagnoses were reported for the National Patient Register and the Causes of Death Register, respectively [32]. Data on sickness absence and disability pension were obtained from economically based registers which indicate compensation received. This type of register is generally considered to be of good quality [7]. Recall bias which is a strong source of bias in studies from clinical samples, was not relevant to the present evaluation.

With regard to study limitations, the present study was based on individuals who were hospitalized for suicide attempts. As it is known that only a quarter of suicide attempters receive inpatient care, the present findings can only be generalized to individuals who have more serious medical conditions that result in hospitalization [33]. Follow-up studies with non-hospitalized suicide attempters are warranted. Further, some individuals might not have received unemployment benefits despite being unemployed. However, in Sweden young unemployed adults who have never worked can have unemployment benefits and are thus included here. Another limitation is that the occurrence of unemployment, sickness absence, and disability pension is affected by regional and temporal changes in social insurance policies and in fluctuations in economic development [34,35]. Risk factors for the specific markers of labour market marginalization may also show some regional and temporal variations. Studies based on different birth cohorts and from different countries are needed in order to analyse potential differences in patterns.