I saw Prof Ismaili give a talk on this a couple of weeks ago. She was very impressive. Her team at KCH are in the running for a major award for this work. Basically earlier research showed diabetics were 3x more likely to suffer from depression, depression correlated with a whole bunch of bad health outcomes including worse HBA1c. Intervention of therapy alone, or diabetes education alone, had no measurable effect, but combining both had a clinically significant effect. She is neutral as to whether DSNs should be trained in CBT, or CBT-trained therapists should be attached to diabetes units, but she believes the key factor is that the therapist should know diabetes as well as knowing CBT, and should be embedded in the diabetes care team.