Somatic depression in the picture: Insights in the comorbidity between somatic diseases and depression

“Why is depression so common among individuals with a somatic disease?”

Depression is very common among individuals with a somatic disease, and is associated with a poor quality of life and worsening of the somatic disease. This dissertation studied explanations for the association between somatic disease and depression.

The results indicated that depression is probably not merely a psychological consequence or a reflection of the somatic disease. In addition, biological and behavioral factors are likely to play an important role in the relation with somatic disease. We found that depression was already more prevalent in individuals with undiagnosed diabetes. Because individuals were unaware of their diabetes, they were not yet confronted with the consequences of having a chronic disease. They were, for instance, not yet dependent on medication and diet prescriptions and not aware of changing future perspectives. In addition, MRI studies indicated a possible biological link. Structural abnormalities in depression-related brain areas were observed in individuals with respectively hypertension and chronic kidney disease. Possibly, a biological vulnerability in the brain may lead to the development of depression as well as somatic disease. In addition, somatic disease may cause damage to the brain, which could lead to the development of depressive symptoms. Finally, behavioral factors associated with depression may also lead to the development and worsening of somatic disease. We observed that cardiac rehabilitation was associated with lower mortality rates specifically for depressed myocardial infarction patients.

Probably, a complex of interactions between psychological, biological, and behavioral factors underlie the relation between somatic disease and depression. Future studies should therefore study these factors in concert.