For example, skeletal muscle represents a major organ for glucose homeostasis, responsible for up to 75% of post-prandial (that is, insulin-stimulated) glucose uptake.27 Low muscle mass might therefore be expected to impair glucose homeostasis and various studies have shown a link between glycaemic control and depression.28, 29, 30 In previous work on obese adolescents with type 2 diabetes, brain abnormalities, such as reduced white matter volume and enlarged cerebrospinal fluid space, have been found, which might result from changes in vascular function and glucose abnormalities.31 Here, INS is linked to depressive symptom measurement.