The findings of an analysis published in Schizophrenia Bulletin associated insulin resistance in childhood with psychotic experiences that preceded the onset of a psychotic disorder.
The authors used a sample of 2627 patients from the Avon Longitudinal Study of Parents and Children, which included 14,062 live births between April 1991 and December 1992. Of the sample, 5.2% at 12 years and 5.4% at 18 years had confirmed psychotic experiences, and 1.4% had been diagnosed with a psychotic disorder at age 18 years.
The authors of the study looked broadly at dysglycemia, including hypoglycemia and hyperglycemia, low-grade inflammation, and psychotic experiences with or without a later diagnosis of a psychotic disorder. Previous research has associated inflammation and dysglycemia with psychosis, and it has also been suggested that inflammation plays a role in the development of type 2 diabetes. The authors sought to clarify some of these relationships.
For markers of dysglycemia, data on fasting plasma glucose levels at ages 9 and 18, 2-hour glucose tolerance results at age 9, and a binary insulin resistance variable were used. Inflammation was marked by levels of the inflammatory cytokine interleukin-6 at age 9 and C-reactive protein at ages 9 and 18.
Insulin resistance was associated with psychotic experiences (odds ratio=2.32, P <.001). Insulin resistance was also associated with interleukin-6 level at age 9 and appeared to moderate, but not mediate, the association of interleukin-6 with psychotic experiences at age 18.
Dysglycemia at age 9 years was not associated with psychotic experiences at age 12 or 18, which the authors noted supported the hypothesis that immune dysfunction might precede dysglycemia in its relationship with psychosis.
The authors described several potential limitations of their analyses, including the possibility of selection bias: only patients who had data available on all relevant variables were included. They also noted that interleukin-6 is only 1 protein among the several that are important to immune activation.
As research on the relationships between these factors continues, the authors advised clinicians to consider carefully which antipsychotic medications they prescribe for their patients with metabolic dysfunction, as some are known to be diabetogenic.
Perry BI, Upthegrove R, Thompson A, et al. Dysglycaemia, inflammation and psychosis: findings from the UK ALSPAC birth cohort [published online April 9, 2018]. Schizophr Bull. doi:10.1093/schbul/sby040