Evaluation of a Diabetes-specific Cognitive Behavioural Treatment for Subthreshold Depression

This work is supported by the "Kompetenznetz Diabetes mellitus (Competence Network for Diabetes mellitus)" funded by the Federal Ministry of Education and Research (FKZ 01GI0809).

Approximately one third of diabetic patients has elevated depressive symptoms. The majority of these patients are suffering from a subthreshold depression. In spite of the fact that subthreshold depression has an equivalent negative impact on the prognosis of diabetes as clinical depression, there is no specific intervention tool. The main objective of this project is to develop a diabetes specific cognitive behavioural treatment (DS-CBT) for diabetic patients with subthreshold depression. In a randomized trail DS-CBT is compared to standard diabetes education. A total of 188 diabetic patients will be recruited and randomly assigned to the two treatment conditions. The expected main outcome is the reduction of subthreshold depression under DS-CBT in a 12 month follow up. Secondary variables are improvement of glycaemic control, quality of life, diabetes self-management as well as reduction of health care costs and modification of inflammatory parameters.

Elevated rates for depression in diabetic patients are of clinical significance for diabetology. Depressive disorders are doubled compared to patients without diabetes. A meta-analysis showed that a proportion of 20% of diabetic patients showed subthreshold depression, defined as elevated depressive symptoms without meeting criteria for clinical depression. Depression in diabetes is associated with a reduced quality of life, more diabetes related distress, and higher health related costs. But besides this, depression in diabetes seems to be an independent negative prognostic factor for morbidity and mortality. Furthermore subthreshold depression is a major barrier of an effective self-management of the disease.

Until now antidepressive therapies are only evaluated in clinically depressed diabetic patients. For the majority of depressed diabetic patients suffering from subthreshold depression no evaluated specific intervention concept exists. Since subthreshold depression often is associated with diabetes related distress a diabetes specific intervention was developed to support patients to increase their problem solving skills, modify their depressive cognitions and improve their coping with diabetes related distress. It consists of five sessions and is delivered as a group intervention.

This study is an efficacy trial. In this randomized trial the efficacy of this newly developed intervention is compared to a control condition consisting of five standard diabetes education lessons. The primary outcome variable is the reduction of depressive symptoms twelve months after the intervention. Secondary outcome variables are the quality of life, metabolic parameters, self-care behavior and other psychosocial aspects. Furthermore the possible covariation between change of depressive symptoms and inflammatory and immune markers will be analyzed.

Eligibility Criteria:
Inclusion Criteria:

* Diabetes mellitus
* Elevated depressive symptoms (regarding to CES-D)
* Age \>= 18 and \<=70
* Sufficient German language skills
* Informed consent

Exclusion Criteria:

* Current MDD
* Current schizophrenia/ psychotic disorder, eating disorder, bipolar disorder, addictive disorder, personality disorder
* Current antidepressive medication
* Current psychotherapy
* Severe physical illness (i.e. cancer)
* Being bedridden
* Guardianship