MedWire News: The brothers and sisters of patients with schizophrenia are more likely to have high concentrations of glucose in their blood than people without a family history of the mental health disorder, study results show.

The findings indicate that the unaffected relatives of patients with schizophrenia, as well as schizophrenia patients themselves, face an increased risk of developing diabetes, say the researchers.

"Some studies suggest that schizophrenia may be associated with an increased risk of diabetes, independently of antipsychotic medications and other confounding factors. Previous studies have also suggested that there is an increased prevalence of diabetes in the relatives of schizophrenia [patients]," explain Dr Brian Kirkpatrick, from the Neuroscience Institute in Barcelona, Spain, and colleagues.

To investigate further, the team studied six unaffected siblings of schizophrenia patients and 12 people from families without a history of schizophrenia or other mental health disorders.

All of the participants, who were aged between 18 and 45 years, underwent glucose tolerance tests.

After accounting for body mass index and other factors, the team found that the participants with a family history of schizophrenia had significantly higher concentrations of glucose in their blood after eating than the other participants.

"Although confirmation with larger samples is needed, these results and other studies suggest that diabetes may share familial risk factors with schizophrenia," the researchers write in the journal Schizophrenia Research.

They add: "Our results provide further, albeit indirect, evidence that prior to antipsychotic treatment, schizophrenia is associated with metabolic abnormalities. This underlying vulnerability may increase the impact of the metabolic side effects of antipsychotic medications."