Up to 30% of patients with type 2 diabetes mellitus report a lifetime history of major depression.2 Depression increases the risk of hyperglycemia and accompanying long-term metabolic complications.4,5 Few studies have explored the effects of poor glycemic control on depressive symptoms among diabetic patients.6-9 A literature review revealed no large-scale study investigating worsened depressive symptoms in patients with poor glycemic control.10,11
The cross-sectional difference between a single episode of major depression and adjustment disorder can be subtle. DSM-IV-TR describes the latter as a maladaptive reaction to an identifiable psychosocial stressor, or stressors, that occurs within 3 months of onset of that stressor (Table 2).12 Because we did not deem Mr. N’s depressive symptoms, which were evident only when he was hyperglycemic, to be grossly disproportionate to his stressors, we diagnose him with major depression rather than adjustment disorder.
Table 2
DSM-IV-TR diagnostic criteria for adjustment disorder
| A. The development of emotional or behavioral symptoms in response to an identifiable stressor(s) that occurs within 3 months of the onset of the stressor(s) |
B. These symptoms or behaviors are clinically significant, as evidenced by either of the following:
|
| C. The stress-related disturbance does not meet criteria for another specific axis I disorder and is not merely an exacerbation of a pre-existing axis I or axis II disorder |
| D. The symptoms do not represent bereavement |
| E. Once the stressor (or its consequences) has terminated, the symptoms do not persist for more than an additional 6 months |
Specify whether the condition is acute or chronic, as follows:
|
| Source: Reference 12 |
EVALUATION: No psychiatric history
On admission, Mr. N is overwhelmed, tearful, and dysphoric when describing his situation. He displays no evidence of psychosis, but his judgment and insight are impaired. He shows no change in consciousness or ability to stay awake. Mr. N acknowledges hypersomnolence, anhedonia, anergia, and decreased concentration and continues to express suicidal and homicidal thoughts. He repeatedly denies any personal or family psychiatric history or personal substance abuse, including alcohol and nicotine.
TREATMENT: Glycemic control
Mr. N receives 1 L of saline in the ED and is encouraged to drink more water during hospitalization. With appropriate insulin dosing, Mr. N’s serum glucose levels improve from 650 to 426 mg/dL by the next morning. On his third hospital day, Mr. N’s glucose level is 155 mg/dL in the morning. With tighter glycemic control, his dysphoria improves. He is future-oriented, markedly less dysphoric, and denies homicidal or suicidal ideation. Mr. N is interested in participating in group therapy, and his insight and judgment regarding his homicidal and suicidal thoughts improve. He still doesn’t fully understand the importance of diabetic control, and he struggles with his diet.
On the fourth hospital day, Mr. N’s glucose level rises to 325 mg/dL in the early evening. Subsequently, his mood deteriorates; he becomes increasingly withdrawn and somnolent. With appropriate attention to his dietary intake and supplemental insulin, his serum glucose improves to the 100 to 200 mg/dL range overnight, and his mood improves. When the glucose is controlled, he attends group therapy, tends to his hygiene, denies feeling hopeless, and offers several ideas about how to manage his family situation. After his glucose rises, Mr. N becomes isolative, hopeless, and unable to cope with stressors. With considerable education about the importance of glycemic control, Mr. N is hopeful and future-oriented when he is discharged after 9 days of hospitalization. At outpatient evaluation, he continues to report euthymia with adequate glycemic control.
The authors’ observations
Patients with hyperglycemia may experience symptoms secondary to volume depletion and hyperosmolality. The severity of these symptoms generally is proportional to the extent and duration of the hyperosmolar state. Initially, most patients complain of polyuria and polydipsia, but in more severe cases, mental status changes may evolve and include lethargy, twitching, cloudiness, motor or sensory defects, seizures, and coma. Some evidence shows that hyperglycemic patients with hyperosmolality are symptomatic only if hypernatremia is present.13 Mr. N was hyponatremic, which resolved with aggressive hydration and insulin administration.
Traditionally, depression has been observed to worsen glycemic control in diabetic patients; discussion of increased glucose levels leading to worsened depression rarely has been reported. In a meta-analysis, Lustman et al7 revealed that depression is significantly associated with hyperglycemia. A review by Li et al14 demonstrated that depression is much more common in patients with diabetes compared with general population and 45% of diabetes patients with depression were undiagnosed. Calhoun et al15 showed that for every 1-unit increase in HbA1c the odds of depressive symptoms increase by 22%. Researchers also found a positive relationship between depression and glycemic control in American Indians.15