Assessing overweight and obesity across mental disorders: personality disorders at high risk

The aim of the present investigation is to assess the prevalence of obesity in people diagnosed as having a mental illness and to investigate differences between disorders. This adds to the paucity of research in this particular population of people and assists with preventative knowledge to obtain optimum physical health.

Data were collected for all 508 male and female inpatients (new and already existing) in a public mental health service centre in Western Australia between January and December 2008. Current weight for all patients and weight gain for some patients were calculated to obtain a body mass index (BMI) value, and diagnostic information was aligned to one of the six major categories of mental illness.

The percentage of obese inpatients (30.3%) was much higher than that of the general population (21.4%), with females showing a higher propensity toward obesity than males. Most diagnostic categories had a mean BMI in the overweight range, whereas Personality Disorders had a mean BMI in the obese range (30.07). A gradual increase in weight over a 9-month time period can be seen in most patients who were assessed on more than one occasion.

The proportion of obese people within the mental health system far exceeds that of the general population, with these people at a much greater risk of becoming obese. The highest level of obesity was found in people with a personality disorder rather than in people with psychosis. Further research is needed to ease out the mitigating factors behind weight gain occurring across disorders.