Edinburgh Research Explorer Association of Mental Disorders in Early Adulthood and Later Psychiatric Hospital Admissions and Mortality in a Cohort Study of More Than 1 Million Men

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. Objective: 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. Results: Diagnosis of mental disorder at conscription or on hospital admission was associated with increased mortality. Age-adjusted hazard ratios (95% confidence intervals) according to diagnoses at Unstructured abstract Mental disorders are linked with increased mortality, but most evidence comes from hospital admissions and underlying mechanisms are unclear. In a cohort study of 1,095,338 male conscripts, we investigated whether the risks of death associated with mental disorders diagnosed at conscription were similar to those associated with admission for these disorders, and examined the role of confounding or mediating factors. Diagnosis of mental disorder at conscription or hospital admission was associated with increased mortality. Age-adjusted hazard ratios (95% confidence intervals) according to diagnoses at conscription ranged from 1.81 (1.54, 2.10) (depressive disorders) to 5.55 (1.79, 17.2) (bipolar disorders). The equivalent figures according to hospital diagnoses ranged from 5.46 (5.06, 5.89) (neurotic/adjustment disorders) to 11.2 (10.4, 12.0) (other substance use disorders) in men born in 1951-8 and increased in men born later. Adjustment for early-life socioeconomic status, BMI and blood pressure had little effect on these associations, but they were partially attenuated by adjustment for smoking, alcohol intake, intelligence, education and later-life socioeconomic position. These associations were not primarily due to deaths from suicide. The increased risk of death associated with mental disorder is not confined to those whose illness requires hospitalisation or to those with psychotic or substance-use disorders. Our findings demonstrate that the increased risk of premature death associated with mental disorder is not confined to those with psychotic or substance-use disorders, or to those whose illness is severe enough to need inpatient care. Neurotic/adjustment disorders, personality disorders, depressive or bipolar disorders, substance use disorders, schizophrenia and other non-affective psychotic disorders were each associated with an increased risk of dying prematurely, even in men who received such a diagnosis during screening for conscription. Smoking, alcohol intake, intelligence and indicators of socioeconomic position in later life may partially mediate the associations between some mental disorders and mortality, though BMI and blood pressure appeared to play little part. If this huge burden of premature mortality is to be reduced, the physical health care of people with mental illness needs to be a greater priority for medical care providers.