Weight gain and obesity in general adult psychiatric inpatients: a longitudinal and cross-sectional study.

Abstract

Weight gain and obesity are significantly linked to mental illness. There have been different theories trying to explain weight gain to psychiatric inpatients, such as physical inactivity and lifestyle, the effect of psychotropic drugs, increased food intake triggered by depression, and comorbidity between mental illness and obesity. The current research is a longitudinal and cross-sectional study collecting the electronic records of weight of psychiatric inpatients in a period spanning from one to ten years to address these theories. We collected the electronic records relative to weight measurement that are conducted weekly and relative to 240 non-forensic psychiatric inpatients (124 males and 116 females) and for a period from 1 to 10 years. Mean ages for males was 39.65 years (SD=±11.66) and females 40.88 years (SD=±13.73). They accessed a psychiatric inpatient service in the United Kingdom. The coefficient of determination R2 calculated the time variation in bodyweight in the period span, while the Chi-square statistic evaluated the differences in outcomes. Our longitudinal study shows that R2=0.17 (95% CI=0.14-0.20) for males and 0.27 (95% CI=02.0-0.34) for females. There was a statistically significant difference between the R2 (c2: p<.05) for both genders. The average Body Mass Index (BMI) for male psychiatric inpatients was 27.05 (SD=±5.92), corresponding to WHO Overweight Class. The average BMI for female psychiatric inpatients was instead 31.21 (SD=±7.73), corresponding to WHO Obesity Class I. The difference in BMI was statistically significant for both genders (c2: p<.001). In our study, only 27% of the difference in body weight in females and 17% in males was explainable by the time variable with a small to moderate effect size. Our findings appear to support the theory that overweight and morbid obesity might be comorbid with psychiatric illnesses and independent from the therapeutic regimen. Overall, females' BMI is more pathological. During lengthy admissions, only modest changes in body weight were observed in our research. Our findings would suggest that metabolic syndrome and therefore elevated BMI, overweight, and obesity might be comorbid with psychiatric illnesses and might be independent of the length of admissions.