Comment Medications commonly used by psychiatrists (e.g., atypical antipsychotics) may be associated with weight gain that exacerbates or precipitates type 2 diabetes.
The psychiatrist also must be aware of other potential medical comorbidities of treatment. Drug-drug interactions may occur with agents that are hepatic metabolized, including commonly used therapies for bipolar disorder (Table 2).
Metglitinides are metabolized by the CYP-3A4 system and drugs such as barbiturates and carbamazepine may induce this enzyme and reduce effectiveness. MAO inhibitors are associated with hypoglycemia with a number of agents, including sulfonylureas, and highly protein-bound agents such as the MAO inhibitors may displace repaglinide and increase its hypoglycemic activity. Fluoxetine and other SSRIs may cause hypoglycemic unawareness. Oral hypoglycemia agents themselves can be associated with hypoglycemia, and the onset may be confused with anxiety or panic attacks. The older sulfonylureas may cause inappropriate ADH (SIADH). Biguanides are occasionally associated with potentially catastrophic lactic acidosis.
Case 3: Disordered eating in an adolescent with type 1 diabetes
B.C., a 17-year-old with type 1 diabetes mellitus, is referred to a psychiatrist for a possible eating disorder. She was diagnosed with diabetes when she was 4. Over the past year her diabetes self-care has become increasingly erratic. B.C.’s mother notes that the patient often skips her insulin altogether, is preoccupied with her weight, and consumes large amounts of junk food. B.C. also admits to purging when she has been particularly lax with her diet.
Interaction between psychiatric and endocrine disorders Disordered eating appears to be frequent in adolescent girls and women with diabetes. Conscious underdosing of insulin and irregular eating habits may occur when patients are concerned about their body image, feel a stigma about using insulin, or fear they won’t fit in with friends.
Diabetes treatment requires a comprehensive approach embracing education, regular history and physical examinations, routine laboratory evaluations, and establishment of counseling goals. The foundation of care lies on appropriate diet and exercise.
Increasingly, a “stepped care approach” to medication is being advocated based on the patient’s stage of disease. For individuals with early type 2 diabetes, risk factor modification, diet, and exercise may be sufficient. Later, as further insulin resistance occurs, oral hypoglycemic agents must be added. A number of therapeutic options are available (Table 1). Finally, late in the course of type 2 diabetes, as absolute insulin deficiency occurs, combination therapy and insulin are used. Insulin is also often required for initial therapy to “rescue” the overstressed beta cells and overcome “glucose toxicity.”
Little evidence exists to guide the choice of treatment of type 2 diabetes, and nuances of therapy are beyond the scope of this article. However, several points are worth reinforcing:
- Ideal treatment is geared to normalizing the blood sugar at all times and achieving a near normal A1c (6.5% to 7%).
- Lifestyle modifications are important, and even relatively small changes in weight can substantially increase insulin sensitivity.
- Risk factor modification (e.g., smoking, lipids, hypertension) is extremely important.
- Therapy for type 2 diabetes is not static. As the disease progresses, more aggressive therapy is often required.
It also appears that depression may be associated with diabetes, perhaps through an intervening effect on diet and exercise. The incidence of depression in patients with diabetes is up to 28%, and women with diabetes appear to have a greater risk for depression than men. Patients with diabetes who are depressed are less likely to adhere to their diabetes program and more likely to have worse glycemic control and increasing risk of complications.
Of course, prevention is the best treatment of diabetes, and promising data are emerging. Increased physical activity (irrespective of BMI) and weight control appear to reduce both the risk of developing type 2 diabetes and the risk of progression from impaired glucose tolerance to overt diabetes. Smoking cessation may also play a role by improving insulin sensitivity. The Diabetes Prevention Program, a multicenter trial sponsored by the National Institutes of Health, should provide definitive data on primary prevention; recommendations based on the initial results of this trial are being developed.
The value of secondary prevention (screening) for type 2 diabetes has been debated. The American Diabetes Association recommends screening all individuals age 45 and older, while the U.S. Preventive Services Task Force suggests there is insufficient evidence to recommend for or against routine screening.
The all-cause mortality rate is doubled for individuals with diabetes. Good data from controlled trials suggest that improved glycemic control diminishes the microvascular complications of diabetes (e.g., retinopathy). A goal of a normal or near normal HbA1c (6.5% to 7.0%) is recommended.
The leading causes of mortality in patients with type 2 diabetes include coronary heart disease and complications of diabetes. The influence on macrovascular complications such as myocardial infarction is less clear. Thus, cardiac risk factors must be managed aggressively.
Diabetic retinopathy is the leading cause of blindness, diabetic nephropathy is the most common reason for end-stage renal disease, and diabetic neuropathy is the most frequent origin of amputation in the United States. Tertiary screening is directed toward early detection and treatment of these complications.