Risk of common psychiatric disorders, suicidal behaviours, and premature mortality following violent victimisation: A matched cohort and sibling-comparison study of 127,628 people who experienced violence in Finland and Sweden.

BACKGROUND: Associations between violent victimisation and psychiatric disorders are hypothesised to be bidirectional, but the role of violent victimisation in the aetiologies of psychiatric disorders and other adverse outcomes remains unclear. We aimed to estimate associations between violent victimisation and subsequent common psychiatric disorders, suicidal behaviours, and premature mortality while accounting for unmeasured familial confounders. METHODS AND FINDINGS: Using nationwide registers, we identified a total of 127,628 individuals born in Finland (1987 to 2004) and Sweden (1973 to 2004) who had experienced violent victimisation, defined as either hospital admissions or secondary care outpatient visits for assault-related injuries. These were age- and sex-matched with up to 10 individuals in the general population (n = 1,276,215). Additionally, we matched those who had experienced violent victimisation with their unaffected siblings (n = 132,408). Outcomes included depression, anxiety, personality disorders, alcohol use disorders, drug use disorders, suicidal behaviours, and premature mortality. Participants were followed from the victimisation date until the date of the outcome, emigration, death, or December 31, 2020, whichever occurred first. Country-specific associations were estimated using stratified Cox regression models, which also accounted for unmeasured familial confounders via sibling comparisons. The country-specific associations were then pooled using meta-analytic models. Among 127,628 patients (69.0% male) who had experienced violent victimisation, the median age at first violent victimisation was 21 (interquartile range: 18 to 26) years. Incidence of all outcomes was larger in those who were exposed to violent victimisation compared to population controls, ranging from 2.3 (95% confidence interval (CI) [2.2; 2.4]) per 1,000 person-years for premature mortality (compared with 0.6, 95% CI [0.6; 0.6], in controls) to 22.5 (95% CI [22.3; 22.8]) per 1,000 person-years for anxiety (compared with 7.3, 95% CI [7.3; 7.4], in controls). In adjusted models, people who had experienced violent victimisation were between 2 to 3 times as likely as their siblings to develop any of the outcomes, ranging from adjusted hazard ratio [aHR] 1.7 (95% CI [1.7; 1.8]) for depression to 3.0 (95% CI [2.9; 3.1]) for drug use disorders. Risks remained elevated 2 years post-victimisation, ranging from aHR 1.4 (95% CI [1.3; 1.5]) for depression to 2.3 (95% CI [2.2; 2.4]) for drug use disorders. Our reliance on secondary care data likely excluded individuals with milder assault-related injuries and less severe psychiatric symptoms, thus suggesting that our estimates may be conservative. Another limitation is the possibility of residual genetic confounding, as full siblings share on average about half of their co-segregating genes. However, the associations remained robust even after adjusting for both measured and unmeasured familial confounders. CONCLUSIONS: In this longitudinal cross-national cohort study, we observed that those who had experienced violent victimisation were at least twice as likely as their unaffected siblings to develop common psychiatric disorders (i.e., depression, anxiety, personality disorder, and alcohol and drug use disorders), engage in suicidal behaviours, and to die prematurely. Importantly, these risk elevations remained 2 years after the first victimisation event. Improving clinical assessment, management, and aftercare psychosocial support could therefore potentially reduce rates of common psychiatric disorders, suicidality, and premature mortality in individuals experiencing violent victimisation.

Socioeconomic differences in children's victimization to maternal and paternal violence: a register-based study.

AIMS: To explore the potential of administrative data in assessment of the association between parental socioeconomic position (SEP) and children's violent victimization by biological parents. METHODS: A longitudinal register-linkage study based on child-mother and child-father data, including all children born in Finland between 1991 and 2017. The data included 1,535,428 children, 796,335 biological mothers, and 775,966 fathers. We used logistic regression with person-years as observations and cluster-robust standard errors to predict children's violent victimization in 2009-2018 and assessed effect modification by child's age and gender. RESULTS: For the SEP indicators, lower maternal education (adjusted odds ratio (OR) 2.90, secondary education OR 1.99) and lower paternal education (OR 2.24, secondary education OR 1.59) were risk factors for violent victimization. Parental social assistance receipt (OR 2.4) and non-employment (OR 1.8-1.9) increased the risk of victimization to maternal and paternal violence. Income was associated with victimization in a gradient-like manner, with ORs ranging from 1.14 to 1.98 among mothers and from 1.29 to 2.56 among fathers. Children with low parental SEP were at the highest risk of parental violence, particularly paternal violence, at ages 3-8 years. CONCLUSIONS: All indicators of low SEP increased the risk of children experiencing both maternal and paternal physical violence, especially at ages 3-8 years. Longitudinal register data-because of large samples, no nonresponse or self-report bias, and the possibility to analyze violence committed by mother and father and age-groups separately-have great potential for comprehensive research on the risk factors of parental violence that are difficult to reliably assess with other types of data.

Adjustment for survey non-participation using record linkage and multiple imputation: A validity assessment exercise using the Health 2000 survey.

AIMS: It is becoming increasingly possible to obtain additional information about health survey participants, though not usually non-participants, via record linkage. We aimed to assess the validity of an assumption underpinning a method developed to mitigate non-participation bias. We use a survey in Finland where it is possible to link both participants and non-participants to administrative registers. Survey-derived alcohol consumption is used as the exemplar outcome. METHODS: Data on participants (85.5%) and true non-participants of the Finnish Health 2000 survey (invited survey sample N=7167 aged 30-79 years) and a contemporaneous register-based population sample (N=496,079) were individually linked to alcohol-related hospitalisation and death records. Applying the methodology to create synthetic observations on non-participants, we created 'inferred samples' (participants and inferred non-participants). Relative differences (RDs) between the inferred sample and the invited survey sample were estimated overall and by education. Five per cent limits were used to define acceptable RDs. RESULTS: Average weekly consumption estimates for men were 129 g and 131 g of alcohol in inferred and invited survey samples, respectively (RD -1.6%; 95% confidence interval (CI) -2.2 to -0.04%) and 35 g for women in both samples (RD -1.1%; 95% CI -2.4 to -0.8%). Estimates for men with secondary levels of education had the greatest RD (-2.4%; 95% CI -3.7 to -1.1%). CONCLUSIONS: The sufficiently small RDs between inferred and invited survey samples support the assumption validity and use of our methodology for adjusting for non-participation. However, the presence of some significant differences means caution is required.

Socioeconomic differences in psychiatric treatment before and after self-harm: an observational study of 4,280 adolescents and young adults.

BACKGROUND: Individuals in higher socioeconomic positions tend to utilise more mental health care, especially specialist services, than those in lower positions. Whether these disparities in treatment exist among adolescents and young adults who self-harm is currently unknown. METHODS: The study is based on Finnish administrative register data on all individuals born 1986-1994. Adolescents and young adults with an episode of self-harm treated in specialised healthcare at ages 16-21 in 2002-2015 (n=4280, 64% female) were identified and followed 2 years before and after the episode. Probabilities of specialised psychiatric inpatient admissions and outpatient visits and purchases of psychotropic medication at different time points relative to self-harm were estimated using generalised estimation equations, multinomial models and cumulative averages. Socioeconomic differences were assessed based on parental education, controlling for income. RESULTS: An educational gradient in specialised treatment and prescription medication was observed, with the highest probabilities of treatment among the adolescents and young adults with the highest educated parents and lowest probabilities among those whose parents had basic education. These differences emerged mostly after self-harm. The probability to not receive any treatment, either in specialised healthcare or psychotropic medication, was highest among youth whose parents had a basic level of education (before self-harm 0.39, 95% CI 0.34-0.43, and after 0.29, 95% CI 0.25-0.33 after) and lowest among youth with higher tertiary educated parents (before self-harm: 0.22, 95% CI 0.18-0.26, and after 0.18, 95% CI 0.14-0.22). The largest differences were observed in inpatient care. CONCLUSIONS: The results suggest that specialised psychiatric care and psychotropic medication use are common among youth who self-harm, but a considerable proportion have no prior or subsequent specialised treatment. The children of parents with lower levels of education are likely to benefit from additional support in initiating and adhering to treatment after an episode of self-harm. Further research on the mechanisms underlying the educational gradient in psychiatric treatment is needed.

Health of Immigrant Children: The Role of Immigrant Generation, Exogamous Family Setting, and Family Material and Social Resources.

Although the children of first-generation immigrants tend to have better health than the native population, the health advantage of the children of immigrant families deteriorates over generations. It is, however, poorly understood where on the generational health assimilation spectrum children with one immigrant and one native parent (i.e., exogamous families) lie, to what extent family resources explain health assimilation, and whether the process of assimilation varies across health conditions. We seek to extend our understanding of the process of health assimilation by analyzing the physical and mental health of immigrant generations, assessing the role of exogamous family arrangements, and testing the contributions of family material and social resources to children's outcomes. We use register-based longitudinal data on all children residing in Finland, born in 1986-2000, and alive in 2000; these data are free of reporting bias and loss to follow-up. We estimate the risk of receiving inpatient and outpatient care for somatic conditions, psychopathological disorders, and injuries by immigrant generation status. Our results show evidence of a negative health assimilation process, with both first- and second-generation immigrant children having a higher prevalence of physical problems and particularly mental health problems than native children that is only partially explained by family resources. We find that the children of exogamous families are at especially high risk of developing psychopathological disorders. These results provide strong support for the hypothesis that children of exogamous families constitute a specific health risk group and that the impact on children's health of family social and material resources seems to be secondary to other unobserved factors.

Alcohol-related Outcomes and All-cause Mortality in the Health 2000 Survey by Participation Status and Compared with the Finnish Population.

BACKGROUND: In the context of declining levels of participation, understanding differences between participants and non-participants in health surveys is increasingly important for reliable measurement of health-related behaviors and their social differentials. This study compared participants and non-participants of the Finnish Health 2000 survey, and participants and a representative sample of the target population, in terms of alcohol-related harms (hospitalizations and deaths) and all-cause mortality. METHODS: We individually linked 6,127 survey participants and 1,040 non-participants, aged 30-79, and a register-based population sample (n = 496,079) to 12 years of subsequent administrative hospital discharge and mortality data. We estimated age-standardized rates and rate ratios for each outcome for non-participants and the population sample relative to participants with and without sampling weights by sex and educational attainment. RESULTS: Harms and mortality were higher in non-participants, relative to participants for both men (rate ratios = 1.5 [95% confidence interval = 1.2, 1.9] for harms; 1.6 [1.3, 2.0] for mortality) and women (2.7 [1.6, 4.4] harms; 1.7 [1.4, 2.0] mortality). Non-participation bias in harms estimates in women increased with education and in all-cause mortality overall. Age-adjusted comparisons between the population sample and sampling weighted participants were inconclusive for differences by sex; however, there were some large differences by educational attainment level. CONCLUSIONS: Rates of harms and mortality in non-participants exceed those in participants. Weighted participants' rates reflected those in the population well by age and sex, but insufficiently by educational attainment. Despite relatively high participation levels (85%), social differentiating factors and levels of harm and mortality were underestimated in the participants.

Adolescent Psychiatric Inpatient Episodes and Subsequent Labor Market Trajectories.

PURPOSE: Adolescents with psychiatric disorders are known to be more often not in education, employment, or training (NEET) in young adulthood than their peers. However, since most of the available evidence is based on cross-sectional measurement of NEET, there is less evidence on the processes underlying these differences in labor market disadvantage. We assessed these processes by examining transitions between NEET and non-NEET states across young adulthood and the differences in these transitions by adolescent psychiatric inpatient treatment. METHODS: We used longitudinal register data on all individuals born in Finland in 1980-1984 (N = 315,508) to identify psychiatric inpatient episodes between ages 10 and 19 and NEET between ages 20 and 34. We modeled the transitions between NEET and non-NEET states and the impact of psychiatric disorders on these transitions with multistate models. RESULTS: Individuals who had psychiatric inpatient episodes in adolescence started their labor market careers as NEET twice as often as their peers. They were also more likely to transition into NEET states and less likely to transition out of NEET. In total, individuals with a history of psychiatric episodes spent from 1.8 to 6.9 more years as NEET between the ages 20 and 34 than their peers, depending on sex, baseline NEET, and diagnostic group. DISCUSSION: Adolescents with severe psychiatric disorders are highly vulnerable in terms of labor market outcomes throughout their early adulthood. Supportive measures are required both at the start of employment trajectories and during later career stages.

Moderating role of sociodemographic factors in parental psychiatric treatment before and after offspring severe self-harm.

BACKGROUND: Parental psychiatric disorders are known risk factors for adolescent self-harm. Although this association is likely to have a bidirectional element, evidence on changes in parental psychiatric treatment following offspring self-harm is scarce. METHODS: Finnish children born in 1987-1996 with a hospital-treated episode of self-harm between the ages 13 and 19 years (N = 3636) were identified using administrative register data, and their biological mothers (N = 3432) and fathers (N = 3167) were followed two years before and after the episode. Data on purchases of psychotropic medication, specialized psychiatric treatment and psychiatric sickness allowances were used to examine psychiatric treatment among parents. Differences by parental education, employment and living arrangements were assessed, and offspring self-harm was compared with offspring accidental poisonings and traffic accidents. RESULTS: Psychiatric treatment peaked among mothers during the three-month period after offspring self-harm, after which the treatment prevalence decreased but remained slightly elevated relative to the time preceding offspring self-harm. Higher levels of education and being employed increased the likelihood of treatment right after the episode. Among fathers, changes in treatment were negligible. Treatment trajectories around the comparison events of accidents were similar in shape but more muted than among the parents whose children had self-harmed. LIMITATIONS: General practitioner visits or other data from primary health care were not available. CONCLUSION: Mothers receive increased psychiatric treatment after stressful offspring events. Our results indicate that prevention of self-harm and accidents would be beneficial not only for those directly concerned but also for their family members.

Offspring hospitalization for substance use and changes in parental mental health: A Finnish register-based study.

Prior research indicates that parental psychiatric disorders increase their offspring's risk of substance use problems. Though the association is likely bidirectional, the effects of an adult child's substance use on parental mental health remain understudied. We examined parents' psychotropic medication use trajectories by parental sex and educational attainment before and after a child's alcohol- or narcotics-attributable hospitalization. We identified Finnish residents, born 1979-1988, with a first hospitalization for substance use during emerging adulthood (ages 18-29, n = 12,851). Their biological mothers (n = 12,283) and/or fathers (n = 10,765) were followed for the two years before and after the hospitalization. Psychotropic medication use was measured in three-month periods centered around the time of child's hospitalization, and the probability of psychotropic medication use at each time point was assessed using generalized estimating equations logit models. Among mothers, the prevalence of psychotropic medication use increased during the year before, peaked during the 0-3 months after hospitalization, and remained at a similarly elevated level until the end of follow-up. The prevalence among fathers increased gradually and linearly across follow-up, with minimal changes evident either directly before or after the hospitalization. Parents' educational attainment did not modify these trajectories. Our results highlight the importance of considering linked lives when quantifying substance use-attributable harms and underscore the need for future research examining the intergenerational spillover effects of substance use in both directions, particularly in mother-child dyads.

Predicting suicide risk in 137,112 people with severe mental illness in Finland: external validation of the Oxford Mental Illness and Suicide tool (OxMIS).

Oxford Mental Illness and Suicide tool (OxMIS) is a standardised, scalable, and transparent instrument for suicide risk assessment in people with severe mental illness (SMI) based on 17 sociodemographic, criminal history, familial, and clinical risk factors. However, alongside most prediction models in psychiatry, external validations are currently lacking. We utilised a Finnish population sample of all persons diagnosed by mental health services with SMI (schizophrenia-spectrum and bipolar disorders) between 1996 and 2017 (n = 137,112). To evaluate the performance of OxMIS, we initially calculated the predicted 12-month suicide risk for each individual by weighting risk factors by effect sizes reported in the original OxMIS prediction model and converted to a probability. This probability was then used to assess the discrimination and calibration of the OxMIS model in this external sample. Within a year of assessment, 1.1% of people with SMI (n = 1475) had died by suicide. The overall discrimination of the tool was good, with an area under the curve of 0.70 (95% confidence interval: 0.69-0.71). The model initially overestimated suicide risks in those with elevated predicted risks of >5% over 12 months (Harrell's Emax = 0.114), which applied to 1.3% (n = 1780) of the cohort. However, when we used a 5% maximum predicted suicide risk threshold as is recommended clinically, the calibration was excellent (ICI = 0.002; Emax = 0.005). Validating clinical prediction tools using routinely collected data can address research gaps in prediction psychiatry and is a necessary step to translating such models into clinical practice.

Physical injuries as triggers for self-harm: a within-individual study of nearly 250 000 injured people with a major psychiatric disorder.

BACKGROUND: Although there is robust evidence for several factors which may precipitate self-harm, the contributions of different physical injuries are largely unknown. OBJECTIVE: To examine whether specific physical injuries are associated with risks of self-harm in people with psychiatric disorders. METHODS: By using population and secondary care registers, we identified all people born in Finland (1955-2000) and Sweden (1948-1993) with schizophrenia-spectrum disorder (n=136 182), bipolar disorder (n=68 437) or depression (n=461 071). Falls, transport-related injury, traumatic brain injury and injury from interpersonal assault were identified within these subsamples. We used conditional logistic regression models adjusted for age and calendar month to compare self-harm risk in the week after each injury to earlier weekly control periods, which allowed us to account for unmeasured confounders, including genetics and early environments. FINDINGS: A total of 249 210 individuals had been diagnosed with a psychiatric disorder and a physical injury during the follow-up. The absolute risk of self-harm after a physical injury ranged between transport-related injury and injury from interpersonal assault (averaging 17.4-37.0 events per 10 000 person-weeks). Risk of self-harm increased by a factor of two to three (adjusted OR: 2.0-2.9) in the week following a physical injury, as compared with earlier, unexposed periods for the same individuals. CONCLUSIONS: Physical injuries are important proximal risk factors for self-harm in people with psychiatric disorders. CLINICAL IMPLICATIONS: Mechanisms underlying the associations could provide treatment targets. When treating patients with psychiatric illnesses, emergency and trauma medical services should actively work in liaison with psychiatric services to implement self-harm prevention strategies.

Long-term Health and Social Outcomes in Children and Adolescents Placed in Out-of-Home Care.

Importance: Children who are placed in out-of-home care may have poorer outcomes in adulthood, on average, compared with their peers, but the direction and magnitude of these associations need clarification. Objective: To estimate associations between being placed in out-of-home care in childhood and adolescence and subsequent risks of experiencing a wide range of social and health outcomes in adulthood following comprehensive adjustments for preplacement factors. Design, Setting, and Participants: This cohort and cosibling study of all children born in Finland between 1986 and 2000 (N = 855 622) monitored each person from their 15th birthday either until the end of the study period (December 2018) or until they migrated, died, or experienced the outcome of interest. Cox and Poisson regression models were used to estimate associations with adjustment for measured confounders (from linked population registers) and unmeasured familial confounders (using sibling comparisons). Data were analyzed from October 2020 to August 2021. Exposures: Placement in out-of-home care up to age 15 years. Main Outcomes and Measures: Through national population, patient, prescription drug, cause of death, and crime registers, 16 specific outcomes were identified across the following categories: psychiatric disorders; low socioeconomic status; injuries and experiencing violence; and antisocial behaviors, suicidality, and premature mortality. Results: A total of 30 127 individuals (3.4%) were identified who had been placed in out-of-home care for a median (interquartile range) period of 1.3 (0.2-5.1) years and 2 (1-3) placement episodes before age 15 years. Compared with their siblings, individuals who had been placed in out-of-home care were 1.4 to 5 times more likely to experience adverse outcomes in adulthood (adjusted hazard ratio [aHR] for those with a fall-related injury, 1.40; 95% CI, 1.25-1.57 and aHR for those with an unintentional poisoning injury, 4.79; 95% CI, 3.56-6.43, respectively). The highest relative risks were observed for those with violent crime arrests (aHR, 4.16; 95% CI, 3.74-4.62; cumulative incidence, 24.6% in individuals who had been placed in out-of-home care vs 5.1% in those who had not), substance misuse (aHR, 4.75; 95% CI, 4.25-5.30; cumulative incidence, 23.2% vs 4.6%), and unintentional poisoning injury (aHR 4.79; 95% CI, 3.56-6.43; cumulative incidence, 3.1% vs 0.6%). Additional adjustments for perinatal factors, childhood behavioral problems, and traumatic injuries, including experiencing violence, did not materially change the findings. Conclusions and Relevance: Out-of-home care placement was associated with a wide range of adverse outcomes in adulthood, which persisted following adjustments for measured preplacement factors and unmeasured familial factors.

Does early drug use-related police contact predict premature mortality and morbidity: A population register-based study.

INTRODUCTION: The aim was to analyse whether age at first drug offense predicts premature mortality and morbidity due to substance use and violence among adolescents and young adults. METHODS: A prospective longitudinal register-linkage study based on a total population sample from Finland including individuals born between 1987 and 1992 and aged 15-25 years during follow-up in 2002-2017 (n = 386 435). Age-specific rates of deaths and health-care admissions (morbidity) during a 5-year follow-up were calculated from the first drug offense. Cox regression models were used to estimate differences in mortality and morbidity at ages 21-25. RESULTS: Of all 15- to 20-year-olds, 1.4% (n = 5540) have had a police contact. The 5-year mortality rates (per 1000 person-years) among those with first drug offense at ages 15-16 was 2.92 [95% confidence interval (CI) 1.56-6.18], and 5.26 (CI 4.00-7.07) and 5.05 (CI 4.06-6.38) at ages 17-18, and 19-20, respectively. The rates of morbidity varied between 61.20 (CI 52.43-71.76) and 87.51 (CI 82.11-93.33). Both mortality and morbidity rates were over 10 times higher than among the general population. In models adjusted for family background, first police contact at an early age (15-16) did not increase the risk of mortality at ages 21-25 compared with first police contact at ages 17-18 (hazard ratio 1.55, CI 0.77-3.09) or 19-20 (hazard ratio 1.52, CI 0.78-2.98). The results were similar for morbidity. DISCUSSION AND CONCLUSIONS: Adolescents with drug-related police contacts have high risk of mortality and morbidity due to substance use and violence regardless of age of first contact.

The effect of low childhood income on self-harm in young adulthood: Mediation by adolescent mental health, behavioural factors and school performance.

Low childhood income is an established risk factor of self-harm in adolescence and young adulthood, and childhood income is additionally associated with various correlates of self-harm. How these correlates, such as psychiatric disorders, substance abuse, violent behaviour and school problems, mediate the effect of childhood income on self-harm, is less understood. The purpose of the current paper is to examine this mediation. The study is based on administrative register data on all Finnish children born in 1990-1995. An analytical sample of 384,121 children is followed from age 8 to 22. We apply the parametric g-formula to study the effect of childhood income on the risk of self-harm in young adulthood. Adolescent psychiatric disorders, substance abuse, prior self-harm, violent criminality and victimization, out-of-home placements, not being in education, employment or training and school performance are considered as potential mediators. We control for confounding factors related to childhood family characteristics. As a hypothetical intervention, we moved those in the lowest childhood income quintile to the second-lowest quintile, which resulted in a 7% reduction in hospital-presenting self-harm in young adulthood among those targeted by the intervention (2% reduction in the total population). 67% of the effect was mediated through the chosen mediators. The results indicate that increases in childhood material resources could protect from self-harm in young adulthood. Moreover, the large proportion of mediation suggests that targeted interventions for high-risk adolescents may be beneficial. To our knowledge, this is the first paper to use the parametric g-formula to study youth self-harm. Future applications are encouraged as the method offers several further opportunities for analysing the complex life course pathways to self-harm.

Trauma and violent offending among adolescents: a birth cohort study.

BACKGROUND: Earlier studies, based on data collected among juvenile court clients or prisoners, suggest that there is an association between trauma and adolescent-onset offending. However, there is a lack of large-scale data on juvenile violence and clinical mental health observations with unselected participants, and a risk-factor-oriented research combining multiple variables affecting violent behaviour. METHODS: We analyse the effect of trauma on violent offending using longitudinal register-linkage population data. The study is based on administrative data on all Finnish children born between 1986 and 2000, linked with their biological and adoptive parents (N=913 675). The data include annually updated demographic and socioeconomic information from Statistics Finland, hospital discharge and specialised outpatient service records as well as the data from all suspected criminal offences known to the police (1996-2017). We measured trauma diagnosis at age 12-14 and followed participants for subsequent violent criminality from age 15 to 17. RESULTS: The population average estimates, taking into account observed substance abuse and other mental health diagnoses, shows that trauma-related disorders (adjustment problems, post-traumatic stress disorder and acute stress disorder) were associated with violent offending. The same was true in sibling fixed effect models, which take into account genetic and environmental confounding shared by siblings. DISCUSSION: These results suggest that severe stress related to traumatic or strong negative life changes in adolescence is a risk factor for violent behaviour.

Experience of maternal and paternal adversities in childhood as determinants of self-harm in adolescence and young adulthood.

INTRODUCTION: Previous studies suggest that childhood experience of parental adversities increases the risk of subsequent offspring self-harm, but studies on distinct paternal and maternal characteristics are few and it remains unclear how these interact with childhood social position. The study aims to assess whether paternal and maternal adversities have different associations with offspring self-harm in adolescence and young adulthood. Interaction by offspring gender and childhood income are investigated, as well as cumulative effects of multiple adversities. METHODS: The study uses administrative register data on a 20% random sample of Finnish households with children aged 0-14 years in 2000. We follow children born in 1986-1998 (n=155 855) from their 13th birthday until 2011. Parental substance abuse, psychiatric disorders, criminality and hospitalisations due to interpersonal violence or self-harm are used to predict offspring self-harm with Cox proportional hazards models. RESULTS: The results show a clear increase in the risk of self-harm among those exposed to maternal or paternal adversities with HRs between 1.5 and 5.4 among boys and 1.7 and 3.9 among girls. The excess risks hold for every measure of maternal and paternal adversities after adjusting for childhood income and parental education. Evidence was found suggesting that low income, accumulation of adversity and female gender may exacerbate the consequences of adversities. CONCLUSIONS: Our findings suggest that both parents' adversities increase the risk of self-harm and that multiple experiences of parental adversities in childhood are especially harmful, regardless of parent gender. Higher levels of childhood income can protect from the negative consequences of adverse experiences.