New Link Between Schizophrenia and Diabetes Discovered

A recent study suggests that patients with early-onset schizophrenia may be at an increased risk of developing diabetes. These results held true even when antipsychotic drugs, diet, and exercise were accounted for.

Schizophrenia is associated with a shortened lifespan of up to 30 years due to other health conditions, such as heart attack and stroke. These conditions are also a risk factor for patients with diabetes.

Additionally, patients with long-term schizophrenia are 3 times more likely to develop diabetes compared with the general population. This link was previously explained by poor diet, antipsychotic use, and inactivity; however, findings from a study published by JAMA Psychiatry indicate that there may be more linking the 2 conditions.

“The mortality gap between people with schizophrenia and the general population is growing, and there is a need for novel approaches to halt this trend,” said first author of the study Toby Pillinger, MA, BM BCh MRCP. “Our study highlights the importance of considering physical health at the onset of schizophrenia, and calls for a more holistic approach to its management, combining physical and mental healthcare.”

In the study, the investigators evaluated whether patients had diabetes at the onset of schizophrenia, before antipsychotics are taken or illness prevents healthy lifestyle habits. The researchers gathered data from 16 different studies, and included 731 patients with schizophrenia and 614 control patients.

After analyzing blood samples from the study participants, the investigators found that patients with schizophrenia had a higher risk of type 2 diabetes compared with control patients, according to the study.

Patients with schizophrenia were more likely to have higher levels of fasting blood glucose compared with the control group. High levels of glucose in the blood indicates that the body cannot remove glucose from cells to use from energy, a characteristic of diabetes.

Compared with healthy patients, patients with schizophrenia had high levels of insulin and insulin resistance, according to the study. These findings suggest that these patients are at an increased risk of developing diabetes.

Even when other factors—such as diet, exercise, and ethnicity— were controlled for, the results remained significant. This means that the findings were not driven by outside factors between the groups, and may point to a direct link between schizophrenia and diabetes, according to the study.

“Our findings tell us that people with early schizophrenia have already started down the road to developing diabetes, even if they haven't been diagnosed with diabetes yet,” Dr Pillinger said.

The study authors believe that genetic risk and developmental risk factors, such as premature birth and low birth-weight, may increase the risk of developing both conditions.

Schizophrenia is associated with stress, and an increase of cortisol, which also may increase the risk of diabetes.

“Given that some antipsychotic drugs may increase the risk of diabetes further, clinicians have a responsibility to select an appropriate antipsychotic at an appropriate dose.” Dr Pillinger concluded. “Our results also suggest that patients should be given better education regarding diet and physical exercise, monitoring, and, where appropriate, early lifestyle changes and treatments to combat the risk of diabetes.'