People who have persistent mental health issues such as depression, bipolar disorder and psychotic illnesses have – on average – a life expectancy that’s around 15 years less than people who don’t have these issues.
The reason is a much higher rate of heart disease, stroke and diabetes. Some of this can be explained by smoking and the side effects of medications – but not all of it. The question some researchers are asking is whether being prone to more severe mental health issues goes along with being innately prone to metabolic problems such as the ability to handle blood sugar.
Sydney researchers have tested this idea in several hundred adolescents and young adults with a range of mental health issues. The reason for targeting young people is that mental health problems usually start in adolescence before lifestyle related metabolic conditions have developed.
Using a sophisticated measure of how well the sugar-reducing hormone insulin works in an individual, they found a significant incidence of insulin resistance, which is where tissues of the body such as muscles, don’t respond to insulin the way they should, largely independent of how fat they were. Insulin resistance can cascade into conditions such as type 2 diabetes.
The message here is that metabolic vulnerability may co-exist with certain psychological problems and it means that when a young person has mental health issues, extra attention must be paid to their physical health including avoiding smoking and weight gain and keeping up physical activity.
