Suicide and mortality related to mental disorder in three Swedish cohorts

Aims: The subject of this thesis is suicide and other premature death relatedto mental disorder. The overall aim is to provide knowledge to improveprevention strategies. The specific aims are as follows: Study I: Toidentify predictors of suicide in a cohort with long-term mentaldisorder. Study II: To analyse mortality by mental health service andpsychiatric diagnosis in a cohort with long-term mental disorder. StudyIII: To investigate the impact of psychiatric morbidity on suicide riskfollowing a suicide attempt. Study IV: To examine familial suicide risksin a total population sample.Methods: Studies I and II. Adult residents with mental disorder in StockholmCounty, Sweden, were identified in 1997. This register (n=12,247) waslinked to national registers. Discharges from psychiatric inpatient careduring 1990 2000 and deaths during 1997 2000 were identified. Predictorsof suicide in the cohort were investigated; standardised mortality ratioswere calculated. Study III. Data on all people living in Sweden 1973 82were linked to national registers. People hospitalised during the period1973 82 due to attempted suicide were identified. The cohort (n=39,685)consisted of those with a studied psychiatric diagnosis present at indexattempt (cases) and those without a psychiatric diagnosis within a yearafter the suicide attempt (reference subjects). Patients were followedfor 21 31 years. Survival curves for suicide were plotted and hazardratios computed. Study IV. A population-based cohort (n=7,969,645) wascreated by linkage of Swedish national registers. Persons with deathclassified as definite or uncertain suicide 1952 2003 were identified(n=83,951). Odds ratios for suicide in relatives of suicide probands werecalculated in relation to relatives of controls.Results: Study I. Predictors of suicide included previous suicide attempt, ahistory of psychiatric inpatient care, and unmet need of a contactperson. Borderline personality disorder was the strongest diagnosticpredictor. Study II. Excess mortality was greater among those with ahistory of psychiatric inpatient care. The number of excess deaths due tonatural causes was threefold that due to external causes. Study III. Highproportions of suicides in all diagnostic groups took place within oneyear. The strongest predictors of completed suicide throughout the entirefollow-up were schizophrenia and bipolar/unipolar disorder, with up to39% suicide mortality. Study IV. The risk increase was threefold infull-siblings and twofold in children. The odds ratio for full-siblingswas higher than that for maternal half-siblings. Odds ratios for second-and third-degree relatives were similar. Partners of suicide probands hada higher odds ratio than most biological relatives.Conclusions: Treatment programs for persons with long-term mental disorder shouldtarget both physical and mental health. Unmet needs may signal increasedsuicide risk in persons with mental disorder. Psychiatric case managementshould focus on more intensive aftercare during the first years after asuicide attempt in patients with bipolar and unipolar disorder orschizophrenia. The findings of Study IV are not entirely consistent withvariance by degree of genetic correlation; the study could identifyimpact of both shared environment and shared genes in familialtransmission of suicidal behaviour.