Somatic comorbidity and its outcomes in schizophrenia during lifespan
Authors: Seppala J. , Korpela H. , Jääskeläinen E. , Miettunen J. , Isohanni M. , Auvinen J. , Nordström T. , Marttila R. , Keinänen-Kiukaanniemi S. , Järvelin M.R. , Salo H. , Rautio N. 
Published: May 2016

Background

Studies mainly relied on hospital or case-control data have well documented that individuals with psychoses, and especially with schizophrenia have increased rates of physical illnesses. They have two to four-fold higher mortality risk, and about 10 to 25 years shorter life expectancy compared with the general population. The aim of this study is to evaluate the prevalence of physical illnesses in individuals with schizophrenia or with other psychoses and among people without psychoses until the age of 46 years using complete outpatient and inpatient data from birth cohort.

Methods

The study is based on The Northern Finland 1966 Birth Cohort (NFBC, 1966), which is a population-based prospective cohort concerning 12.058 live-born children in 1966 in the provinces of Lapland and Oulu.

The study population consisted of 10,933 individuals, who were alive at the age of 16-years, and followed serially until the age of 46-years The study population was divided into three groups: those having schizophrenia (n = 228) and those with other psychoses (n = 240) while individuals without psychosis (n = 10,465) formed the control group. The data was obtained from various national registers.

Results

Diseases of the blood and blood forming organs (prevalence in SCZ was 17% versus 10% in controls, P < 0.001), endocrine, nutritional and metabolic diseases (45% vs. 27%, P < 0.001), diabetes mellitus (7% vs. 3%, P < 0.001) and nervous diseases (33% vs. 25%, P = 0.018) were more common among individuals with SCZ compared with controls. Diseases of musculoskeletal system and connective tissue were less common in SCZ than among controls (28% vs. 41%, P < 0.001).

People with other psychoses than SCZ had statistically significant association with all the diagnostic groups classified in ICD-10 except with neoplasms. Infections and parasitic diseases (prevalence in other psychoses was 44% versus 32% in controls, P < 0.001), diseases of the blood and blood forming organs (18% vs. 10%, P < 0.001), endocrine, nutritional and metabolic diseases (42% vs. 27%, P < 0.001) including diabetes mellitus (9% vs. 3%, P < 0.001), nervous diseases (40% vs. 25%, P < 0.001), diseases of the eye and adnexa (32% vs. 21%, P < 0.001), diseases of the ear and mastoid process (58% vs. 44%, P < 0.001), diseases of circulatory (50% vs. 37%, P < 0.001), respiratory (70% vs. 60%, P < 0.001) and digestive system (77% vs. 68%, P = 0.004), diseases of skin and subcutaneous tissue (23% vs. 16%, P = 0.006), diseases of musculoskeletal system and connective tissue (51% vs. 40%, P = 0.004) and diseases of genitourinary system (41% vs. 31%, P = 0.003) were more common among people with other psychoses than SCZ compared with controls.

Discussion

A new finding is that not only people with schizophrenia but especially those with other psychoses show a greater occurrence of somatic diseases compared with those without psychosis. The increased occurrence of somatic comorbidity in other psychoses should be noted by medical professional, and further longitudinal studies are warranted to study its possible risk factors during lifespan.

Disclosure of interest

The authors have not supplied their declaration of competing interest.