While everyone is aware of the obesity crisis, few understand that the link between obesity and mental health disorders is especially profound. A 20-year study now suggests obesity plays a prime factor for early deaths among people with schizophrenia and bipolar disorder.

The research helps to explain why the lifespan for those with schizophrenia is 20 years shorter than the general population and 10 years shorter for those with bipolar disorder. Interestingly, researchers discovered weight gain was not linked to use of antipsychotic medications.

Obesity is a major public health problem in the United States, as an estimated 35 percent of Americans are obese and have a body mass index (BMI) of 30 or more. In addition, the 2.2 million Americans with schizophrenia and the 5.7 million Americans with bipolar disorder, have an even greater incidence of obesity, with the risk factor accompanied by a greater chance of type II diabetes and cardiovascular disease.

In a first-of-its-kind study, Florida Atlantic University (FAU) researchers discovered that bigger waistlines and the way body fat is distributed are largely to blame for the shorter lifespan. The study appears in the international journal Bipolar Disorders, and is the first to compare the long-term course of weight across different psychotic disorders.

In the study, researchers from FAU’s developed the most comprehensive weight-gain trajectory for schizophrenia and bipolar disorder available to date. The study is the first to compare the long-term course of weight across different psychotic disorders.

Investigators developed their model from data carefully collected by Evelyn Bromet, Ph.D., and colleagues at Stony Brook University. They believe the findings will provide vital information to fill the gap that exists today for clinicians to pinpoint the critical time periods that would lend themselves to prevention and intervention.

“Most clinical trials for psychotic disorders are limited to cross-sectional or short-term studies that typically last one year or less,” said Martin T. Strassnig, M.D., lead author of the study and associate professor of Integrated Medical Science in FAU’s College of Medicine.

“These trials are not long enough to determine the best timing for intervention. Moreover, if there are weight differences in schizophrenia and bipolar disorder patients, we need to tailor prevention and intervention efforts specific to their needs.”

Strassnig and his collaborators obtained data for their study from a carefully conducted 20-year study in a well-controlled epidemiological setting of a countywide sample of first-admission patients hospitalized with a psychotic condition in the early 1990s.

Study participants ranged in age from 15 to 60 years, and excluded those with a psychosis related to depression, substance use and other psychoses. The study included in-person follow-ups, which occurred at six months, and at two, four, 10, and 20 years after their first admission.

In the study, FAU researchers looked at weight and height measurements as well as biomarkers such as blood pressure, cholesterol, triglycerides, hemoglobin A1C, body fat percentage, and waist circumference. Weight gain was defined by a standard measure of BMI.

Key findings from the study revealed that cholesterol, triglycerides, hemoglobin A1C, and blood pressure were not correlated with BMI in the group as a whole.

However, over the 20-year study, body fat and waist circumference were substantially linked with an increase in BMI. Researchers discovered waist circumference at year 20 was significantly higher in schizophrenia than in bipolar disorder, and that women with schizophrenia had higher waist circumferences than men or women with bipolar disorder.

In both bipolar disorder and schizophrenia, increasing waist size made the biggest difference in BMI. This suggests a central obesity pattern reflecting fat buildup on central organs.

Being overweight early in the course of the disorder predicted future weight gain. Results also show that nearly two-thirds of those with schizophrenia and more than half of those with bipolar disorder were obese 20 years after their first hospitalization for psychosis.

Investigators discovered the schizophrenia group gained twice as much weight within the first 10 years, while those with bipolar disorder experienced less weight gain during the initial 10-year period compared to the subsequent 10 years.

“Interestingly, the use of antipsychotic medication was not associated with longitudinal differences in the course of weight gain, nor was the type or availability of antipsychotics,” said Strassnig.

“In fact, during years 10 to 20, when the likelihood of being exposed to the group of weight gain-causing second-generation drugs was greatest, there is evidence of plateauing of weight gain.

Moreover, neither gender nor race was associated with the rate of weight gain post baseline.”

The researchers stress that because weight gain continues for 20 years, interventions can be effective in mitigating further weight gain even many years into treatment. Finally, another important conclusion they draw from their data is that waist circumference should be measured frequently, especially in women with schizophrenia.

Source: Florida Atlantic University

Weight Gain Associated with Psychotic Disorders is Life Limiting