Bipolar disorders and diabetes go hand in hand
Diabetes occurs in hospitalized bipolar patients at a rate almost three times the national average of healthy people, suggesting a link between the two diseases, say Duke University researchers in a study published in the September issue of the Journal of Psychiatry.
In a study of 345 patients with bipolar disorders, the Duke team found diabetes in about 10% of the hospitalized patients, which is significantly higher than the 3.4% frequency rate in demographically similar groupings in the general U.S. population.
"This increased incidence of diabetes kept hitting us in the face, and so we decided to take a closer look," says lead researcher Frederick Cassidy, MD, a clinical associate in psychiatry at Duke University Medical Center in Durham, NC.
"Clearly people who are manic-depressive are at risk," he says. "Clinicians need to be attentive and screen for diabetes in a bipolar population."
Conversely, other experts suggest clinicians should consider bipolar disorder when diabetic patients present with depression.
While the patients in the Duke study were all hospitalized, Cassidy theorizes that the association with diabetes would likely hold true with the general population of patients diagnosed with bipolar disorder, since most of them are hospitalized only intermittently to treat acute mania or acute depression. He says diabetes may be a comorbidity of bipolar disorder or vice-versa. There may be a genetic relationship between the two diseases, a causal relationship in which one increases the risk of the other, or a functionally overlapping disturbance present in both diseases.
Manic episodes may also contribute to the development of diabetes because of the increased glucocorticoids and hypercortisolemia that has been reported during depressive episodes, Cassidy says.
Few studies have looked at cerebrovascular disease in diabetics, but some have reported higher rates of lesions of small cerebral vessels.
He also speculates that the sedentary lifestyle and weight gain associated with psychoses could contribute to these patients’ risk of developing diabetes. Newer psychotropic medications can be associated with increased glucose in many patients, he adds.
Even the older medications used to treat bipolar disorders may contribute to the development of diabetes, says Fred Goodwin, MD, director of the Center on Neuroscience, Medicine, Progress, and Society at George Washington University in Washington, DC.
For example, he says lithium has an anti-insulin effect. Diabetic patients taking lithium need to make dietary alterations and severely restrict simple carbohydrates. Many begin "chasing" their blood sugar as they gain weight, resulting in further weight gain and poor control.
Goodwin says he has also noticed that there seems to be a pattern of diabetes and bipolar disorders running in families. He suggests taking a family history and noting any diabetic patient with a first-degree relative with manic-depression should be screened for bipolar disorder by a psychiatrist.
He also notes that recent studies show a connection between diabetes and depression. "Often, we make the mistake of treating depression with anti-depressants in the absence of mood stabilizers, which can make the depression cycle more rapidly and convert simple depression into a bipolar disorder." Clinicians treating diabetics with a family history of bipolar disorder should get a psychiatric consultation, he says.
Risk factors for bipolar disorders include:
- The patient experiences a first depression before the age of 30 — the earlier the age of the first depression, the higher the likelihood of bipolar disorder.
- He experiences a major depression every year or two.
- There is a family history of bipolar disorder.
- Patient experiences irritability.
- He sleeps only brief periods of time, often not more than 2 hours in 24.
- The patient reports enormous energy and brags about it.
- He has erratic spending habits and poor impulse control.
- The patient remembers manic periods as the good times.
Don’t rely on the patient as the only source of information, says Goodwin. Get information from a spouse or family member. "You’ll miss half of the cases if you interview only the patient," Goodwin says.
[Contact Frederick Cassidy at (919) 575-7801 and Fred Goodwin at (202) 994-1014.]
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