News reports of an epidemic of diabetes are not exaggerated: An estimated 21 million Americans are affected with the metabolic disorder.
Many will require psychiatric care. Diabetic patients are twice as likely as the general population to suffer from depression, and individuals with depression are at comparably higher risk of developing type 2 diabetes. Although anxiety disorders have been less studied in this regard, some surveys have found the prevalence of generalized anxiety disorder (GAD) among people with diabetes to be 14%--well above the norm--with increased rates of specific phobias as well. It has been widely publicized that schizophrenia and some drugs used to treat it are associated with a heightened risk for type 2 diabetes.
One condition often compromises management of the other. "People with diabetes who are depressed are less likely to adhere to their diet or to exercise, and more likely to smoke. They have higher [body mass indexes] and more lapses in medications needed to control their condition," said Dr. Wayne J. Katon, professor of psychiatry at the University of Washington, Seattle.
Anxiety may likewise impair self-care among those with diabetes, said Dr. Eduardo A. Colon, vice chief of psychiatry at Hennepin County Medical Center, Minn., and professor of psychiatry at the University of Minnesota, Minneapolis.
"These patients are less able to cook for themselves, go grocery shopping, do glucose testing. An anxious patient who has had an episode of hypoglycemia may refuse to lower his blood sugar to an adequate level because tighter glucose control makes further episodes more likely," he said.
From a biologic perspective, disturbance of the hypothalamic-pituitary axis in depression can increase secretion of cortisol and catecholamines, which has a negative impact on insulin sensitivity and glucose regulation, Dr. Colon said.
For whatever reason, psychiatric comorbidity negatively affects the course of diabetes. Dr. Katon's study of 4,800 diabetics found a cross-sectional association with a higher number of diabetes complications, and over a 3-year period, depression was associated with a twofold increase in mortality, "even after we controlled for the greater initial severity of disease in depressed versus nondepressed diabetic patients," Dr. Katon said.
The treatment of psychiatric disorders in the context of diabetes represents a challenge. "These patients already have a medical condition that's complicated to manage, and the difficulty can be compounded by antidepressants," said Dr. Alan M. Jacobson, director of mental health programs at the Joslin Diabetes Center and professor of psychiatry at Harvard Medical School, Boston.
"One needs to take both disorders into account in selecting psychotropics and titrating them to their optimal level," he noted.
Tricyclics can increase blood sugar levels, and selective serotonin reuptake inhibitors reduce them. "Patients should be encouraged to test their blood sugar more often when starting an antidepressant or changing the dosage, and make adjustments in insulin or oral agents accordingly," Dr. Jacobson said.
Concurrent diabetes may compromise adherence to a psychotropic regimen: A patient who is already taking several drugs (a regimen will frequently address cardiovascular risk as well as diabetes) and making the life changes required by diabetes management may find it difficult to accommodate treatment for another disorder, Dr. Katon said.
Little controlled research has been done on this issue, but it appears the standard drugs for anxiety and depression are reasonably safe and effective for those with diabetes. Choosing among them may mean matching diabetes manifestations against psychotropic effects and side effects.
For example, weight control is of particular concern in diabetes, and sexual dysfunction is common as well. …