Association of mental disorders in early adulthood and later psychiatric hospital admissions and mortality in a cohort study of more than 1 million men.

Abstract

Context: Mental disorders have been associated with increased mortality, but the evidence is primarily based on hospital admissions for psychoses. The underlying mechanisms are unclear.

Objectives: To investigate whether the risks of death associated with mental disorders diagnosed in young men are similar to those associated with admission for these disorders and to examine the role of confounding or mediating factors.

Design: Prospective cohort study in which mental disorders were assessed by psychiatric interview during a medical examination on conscription for military service at a mean age of 18.3 years and data on psychiatric hospital admissions and mortality during a mean 22.6 years of follow-up were obtained from national registers.

Setting: Sweden.

Participants: A total of 1,095,338 men conscripted between 1969 and 1994.

Main outcome measure: All-cause mortality according to diagnoses of schizophrenia, other nonaffective psychoses, bipolar or depressive disorders, neurotic and adjustment disorders, personality disorders, and alcohol-related or other substance use disorders at conscription and on hospital admission.

Results: Diagnosis of mental disorder at conscription or on hospital admission was associated with increased mortality. Age-adjusted hazard ratios according to diagnoses at conscription ranged from 1.81 (95% CI, 1.54-2.10) (depressive disorders) to 5.55 (95% CI, 1.79-17.2) (bipolar disorders). The equivalent figures according to hospital diagnoses ranged from 5.46 (95% CI, 5.06-5.89) (neurotic and adjustment disorders) to 11.2 (95% CI, 10.4-12.0) (other substance use disorders) in men born from 1951 to 1958 and increased in men born later. Adjustment for early-life socioeconomic status, body mass index, and blood pressure had little effect on these associations, but they were partially attenuated by adjustment for smoking, alcohol intake, intelligence, educational level, and late-life socioeconomic status. These associations were not primarily due to deaths from suicide.

Conclusion: The increased risk of premature death associated with mental disorder is not confined to those whose illness is severe enough for hospitalization or those with psychotic or substance use disorders.