Inflammation may predict how well people with diabetes respond to depression treatment, and the effects differ dramatically between type 1 and type 2 diabetes, according to a new study that offers a path towards personalized mental health care.
Diabetes and depression often appear together. Indeed, depression is more than three times more prevalent in people with type 1 diabetes (T1D) and nearly twice as prevalent in people with type 2 diabetes (T2D). When they appear together, treatment for depression can vary widely.
In a new study, researchers from the German Diabetes Center (DDZ), the Research Institute of the Diabetes Academy Mergentheim (FIDAM), and the German Center for Diabetes Research (DZD) investigated how inflammation in the body relates to improvement in depression symptoms in people with T1D and T2D.
“People with type 2 diabetes and high inflammation levels possibly respond particularly well to a change in depressive cognitions through cognitive behavioral therapy,” said one of the study’s senior authors, Professor Norbert Hermanns, from DZD and the FIDAM. “People with type 1 diabetes and high inflammation levels, on the other hand, could benefit more from anti-inflammatory drug therapies.”
The researchers combined data from three previous German randomized clinical trials that aimed to reduce elevated depressive symptoms and diabetes distress in people with type 1 or type 2 diabetes. Diabetes distress is characterized by feelings of overwhelm, frustration, guilt and worry about diabetes management and its potential complications. A total of 332 participants with T1D and 189 with T2D who had completed both a baseline and 12-month follow-up examination were included in the present study. Measures included depression using the Center for Epidemiological Studies Depression scale (CES-D), blood tests for 76 inflammatory biomarkers, and symptoms broken down into cognitive-affective (e.g., feeling hopeless), somatic (e.g., poor sleep, fatigue), and anhedonia (loss of pleasure) clusters.
After adjusting for factors like age, body mass index (BMI), diabetes duration, cholesterol, and co-existing illnesses, the researchers found that in patients with T1D, higher baseline inflammation was linked to smaller improvements in depression. Inflammation seemed to be more connected to physical/somatic symptoms in T1D patients. In those with T2D, higher baseline inflammation was linked to greater improvements in depression. For these patients, the effect was strongest for cognitive-affective and anhedonia – so, emotional and motivational – symptoms.
The researchers weren’t sure what caused the difference between T1D and T2D, but they suggest it might be due to the different forms of immune activation seen in each condition. That is, autoimmune processes in type 1 and metabolic inflammation in type 2.
The study had some limitations. Only non-drug – psychological and educational – interventions were studied, so results may not apply to antidepressant treatment. Participants already had elevated depressive symptoms or distress, so findings may not generalize to milder cases or severe major depression. Most participants were of European descent, so results might not apply to other ethnic backgrounds. There were no follow-up biomarker measurements taken, so the researchers couldn’t track how inflammation levels change with symptom improvement. And, the research can only establish associations, not cause-and-effect.
What the study’s findings do suggest is that blood tests for inflammatory markers could help guide personalized depression treatment in people with diabetes. For type 1 diabetics with high inflammation, additional anti-inflammatory approaches might be needed to improve depressive symptoms, especially physical symptoms. Whereas, for type 2 diabetics, psychological therapies may be particularly effective, especially for emotional and motivational symptoms.
“Further studies are needed to better understand the underlying mechanisms and the role of psychotherapeutic and anti-inflammatory treatment approaches,” said co-author Professor Michael Roden, Scientific Director and Spokesperson of the DDZ Board and Director of the Department of Endocrinology and Diabetology at the University Hospital of Düsseldorf.
The study was published in the journal Diabetologia.
Source: DZD
