Prescribing patterns for glucose-lowering medication appear to differ in the presence of severe mental illness (SMI). Published in Diabetes, Obesity and Metabolism, this population-based cohort study examined whether adults with type 2 diabetes and pre-existing SMI received metformin or insulin earlier than those without SMI.

The analysis included 317,761 adults in Scotland newly diagnosed with type 2 diabetes between 2004 and 2022. Fourteen thousand six hundred individuals (4.6%) had a prior hospital admission for schizophrenia, bipolar disorder, or depression. Over a median follow-up of 1.6 years, metformin was initiated in 74% with SMI and 73% without SMI, while adjusted Cox models showed earlier initiation of both metformin and insulin in those with SMI. Sensitivity analyses restricted to participants with body mass index data yielded similar estimates.

The findings indicate that individuals with SMI begin metformin and insulin sooner after a diabetes diagnosis. Further research is needed to clarify whether this reflects earlier metabolic decline, closer clinical monitoring, or differences in baseline risk that influence prescribing decisions.