Patterns of tobacco-related mortality among individuals diagnosed with schizophrenia, bipolar disorder, or depression

Abstract

Even though individuals with psychiatric conditions have a prevalence of smoking approximately 2-4 times greater than the general population, surprisingly little evidence exists to inform an assessment of the full range of tobacco-related mortality in such populations. The current study aims to provide mortality estimates for conditions causally related to tobacco use among individuals hospitalized with a primary psychiatric diagnosis in California from 1990 to 2005. Restricting cases to those of individuals aged 35 or older at the mid-point of their follow-up period, we assembled cohorts of individuals with ICD-9 diagnoses of schizophrenia and related disorders ("schizophrenia"; n = 174,277), depressive disorders (n = 338,250), or bipolar disorder (n = 78,739). Inpatient records were linked to death-certificate data. We generated age-, sex-, and race-adjusted standardized mortality ratios (SMRs) for the 19 diseases identified by the Centers for Disease Control and Prevention as being causally linked to tobacco use. The SMRs for all tobacco-linked diseases combined were: schizophrenia, 2.45 (95% CI = 2.41-2.48); bipolar, 1.57 (95% CI = 1.53-1.62); and depression, 1.95 (95% CI = 1.93-1.98). Tobacco-related conditions comprised approximately 53% (23,620/44,469) of total deaths in the schizophrenia, 48% (6004/12,564) in the bipolar, and 50% (35,729/71,058) in the depression cohorts. Addressing tobacco use in psychiatric populations is a critical clinical and public-health concern, especially in light of the currently limited clinical attention devoted to tobacco use in these groups.

Keywords: Bipolar disorder; Depression; Schizophrenia; Standardized mortality rates; Tobacco-related conditions.