The mechanism or pathogenesis that underlies the strong association between depression and diabetes is poorly understood but there are tentative models to explain the co-morbidity. The conventional model, namely that the psychological burden of living with diabetes leads to higher rates of depression, is not fully supported by the current evidence. Additional models include

1. a) the possibility of shared developmental origins between diabetes and depression

2. b) the direct effects of hyperglycaemia, hypoglycaemia and related metabolic dysfunction on the brain and

3. c) common mediators such as chronic stress response leading to pro-inflammation.

The potential for research into the above postulated pathways is vast and may lead to identification of new modifiable targets for intervention.