Symptoms of Depression in Patients With Type IT Diabetes Mellitus LIANE LEEDOM, M.D. WOERNER P. MEEHAN, PH.D. WARREN PROCCI, M.D., PH.D. ADINA ZEIDLER, M.D.
Patients with type II diabetes mellitus were assessedfor symptoms ofdepression using the Zung Self-Rated Depression Scale (Zung SDS) and the Beck Depression Inventory (BDl). The patients were classified according to the presence or absence ofdiabetic complications. and they were compared with a group ofdemographically matched, nonmedically ill control subjects. The patients with diabetic complications scored significantly higher on the depression inventories than did the patients without complications and the control subjects. Factor analysis ofBDI responses revealed that cognitive symptoms of depression were prominent in the diabetic patients with complications. In this group, 74% ofpatients scored within the range of clinical depression on the BDI; 35% scored within the range ofsel'ere depression. Symptoms ofsexual dysfunction were significantly correlated with symptoms ofdepression in diabetic women but not in diabetic men. The findings are discussed within the context ofother research in the behavioral aspects ofdiabetes mellitus.
R
ecently, attention has been given to the neurochemical concomitants of experimental diabetes mellitus in animals. Changes in the neurochemistry of central serotonergic. noradrenergic. and dopaminergic systems occur with diabetes (for a review. see Leedom and Meehan'). It may be hypothesized that the decrease in monoaminergic function seen in diabetes mellitus might produce a diathesis to
Received December I. 1989; revised April 26. 1990; accepted May 4. 1990. From the Departmenl of Psychiatry. Harbor/UCLA Medical Cenler. Torrance. California; and the Section of Diabetes and Clinical Nutrition. Departmenl of Medicine. LAC/USC Medical Center. Los Angeles. Address reprint requests to Dr. Leedom. Departmenl of Psychiatry. Harbor/UCLA. 1000 W. Carson. Torrance. CA 90509. Copyright © 1991 The Academy of Psychosomatic Medicine.
280
depression in affected patients. Preliminary research indicates that patients with diabetes mellitus are likely to experience symptoms of depression. Murawski et at. studied personality patterns in patients with diabetes (type unknown) and found elevations in the depression subscale of the Minnesota Multiphasic Personality Inventory (MMPI) in patients with and without complications. 2 Surridge et at. reported that about one-quarter of a group of type I diabetic patients seemed sad or blue. but none met diagnostic criteria for major depression. 3 Friis and Nanjundappa investigated the relationship between unemployment and depression inventory scores in types I and II diabetes. 4 Diabetes was associated with both unemployment and elevated depression inventory scores; however. unemployment did not explain the elePSYCHOSOMATICS
Leedom et al.
vated depression inventory scores seen in diabetic patients. Lustman et al. utilized the Diagnostic Interview Scale (DIS) in order to determine the lifetime prevalence of psychiatric disorders in a group of 114 diabetic patients (57 type I, 57 type 11). 5 Lifetime prevalence rates for major depression and for dysthymic disorder were 36% and 17.5%, respectively, in the entire sample. Similarly, Popkin et al. utilized the same instrument to examine 75 type I diabetic patients with severe complications.6 The lifetime and 6month prevalence rates were 24% and 10.7% for major depression and 3% and 0% for dysthymic disorder. Since the vegetative symptoms of depression are similar to the somatic symptoms of diabetes mellitus, depression may be diagnosed (by self-report inventories or structured interview) in individuals who are not depressed. In an examination of this issue, Lustman et al. 5 excluded somatic symptoms from DIS diagnostic criteria and found very little effect of these symptoms on the observed prevalence of major depression and dysthymic disorder in diabetic patients. Although one well-designed study found a strong association between diabetic control and symptoms of depression and anxiety, 7 two other studies did not confirm these results. 2•B The complications of diabetes include, among other conditions, progressive blindness, renal failure, and chronic pain. It is expected that patients with such complications would be likely to experience symptoms of depression. Murawski et al. found that MMPI-Depression Scale scores were equally elevated in diabetic patients with and without complications. 2 Geringer et al. studied a group of 64 type II diabetic women. 9 A significant relationship was found between the degree of neuropathy and the degree of depression in those patients whose Zung Self-Rated Depression Scale (Zung SDS) scores were within the range of clinical depression. Turkington reported that pharmacological treatment of depression in patients with painful diabetic neuropathy resulted in resolution of both pain and depression. 1O To summarize, recent studies have indicated VOLUME 32· NUMBER 3· SUMMER 1991
a possible relationship between diabetic complications and symptoms of depression, as well as between diabetic control and symptoms of depression. Considering that the basic pathophysiologic mechanisms for metabolic control may be different in type I and type II diabetes, it may be important to study psychiatric symptoms in these two patient populations separately. The purpose of the present study was to examine symptoms of depression in patients with type II diabetes mellitus and to determine the prevalence of these symptoms. We chose to restrict our study to type II diabetic patients (noninsulin-dependent) because this group represents 80% of patients with diabetes mellitus. Symptoms of depression in patients with diabetic complications were compared to those in patients without complications and normal control subjects. Symptoms of sexual dysfunction were assessed and related to symptoms of depression and the presence of other diabetic complications. METHODS Subjects Type II diabetic subjects included 113 consecutive English-speaking patients from the outpatient diabetes clinic at LAC/USC Medical Center. All patients had random plasma glucose less than 300 mg/dl at the time of the study, and none had symptomatic hypoglycemia. All were between the ages of 30 and 70. Patients were told that as part of a study of mood changes and sexuality in diabetes, their medical histories would be reviewed; they would fill out questionnaires and undergo physical examination. Of the initial 113 patients, 26 refused to participate; 9 were excluded because of intercurrent illness (stroke n=3, lupus erythematosus n= I, hypothyroidism n=3, sarcoidosis n=l, and lymphoma n= I); 5 were excluded because of psychosis, and 2 because of alcoholism. Overall, the pool of 41 subjects who refused or who were excluded did not differ significantly in demographic characteristics from the 71 patients who participated in the study. Normal control subjects included 46 consec281
Depression and Type II Diabetes Mellitus
utive nonmedically ill visitors in the waiting area of the clinic. These subjects were told they were acting as a comparison group in a study of moods and sexuality in patients with diabetes. The control subjects were 31 women and 13 men with an average age of 46±1.7 (mean±SEM) years. There were 4 Asians. 21 blacks. II Caucasians. and 10 Hispanics. The diabetic patients were 50 women and 21 men with an average age of 50±2.0 years. There were 2 Asians. 28 blacks, 13 Caucasians, and 28 Hispanics. Fifty percent of the control subjects and 28% of the diabetic subjects were employed (X~=9.52. p
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FIGURE 2.
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_
Zun\t Self·Rated Depression Scale (Zung SOSI scores for control subjects. diabetic patients without complications. and diabetic patients with complications. 80th groups of diabetic patients scored signilicantl}' higher than controls on the Zung SOS (·,,
Patients with type II diabetes mellitus were assessedfor symptoms ofdepression using the Zung Self-Rated Depression Scale (Zung SDS) and the Beck Depression Inventory (BDl). The patients were classified according to the presence or absence ofdiabetic complications. and they were compared with a group ofdemographically matched, nonmedically ill control subjects. The patients with diabetic complications scored significantly higher on the depression inventories than did the patients without complications and the control subjects. Factor analysis ofBDI responses revealed that cognitive symptoms of depression were prominent in the diabetic patients with complications. In this group, 74% ofpatients scored within the range of clinical depression on the BDI; 35% scored within the range ofsel'ere depression. Symptoms ofsexual dysfunction were significantly correlated with symptoms ofdepression in diabetic women but not in diabetic men. The findings are discussed within the context ofother research in the behavioral aspects ofdiabetes mellitus.
R
ecently, attention has been given to the neurochemical concomitants of experimental diabetes mellitus in animals. Changes in the neurochemistry of central serotonergic. noradrenergic. and dopaminergic systems occur with diabetes (for a review. see Leedom and Meehan'). It may be hypothesized that the decrease in monoaminergic function seen in diabetes mellitus might produce a diathesis to
Received December I. 1989; revised April 26. 1990; accepted May 4. 1990. From the Departmenl of Psychiatry. Harbor/UCLA Medical Cenler. Torrance. California; and the Section of Diabetes and Clinical Nutrition. Departmenl of Medicine. LAC/USC Medical Center. Los Angeles. Address reprint requests to Dr. Leedom. Departmenl of Psychiatry. Harbor/UCLA. 1000 W. Carson. Torrance. CA 90509. Copyright © 1991 The Academy of Psychosomatic Medicine.
280
depression in affected patients. Preliminary research indicates that patients with diabetes mellitus are likely to experience symptoms of depression. Murawski et at. studied personality patterns in patients with diabetes (type unknown) and found elevations in the depression subscale of the Minnesota Multiphasic Personality Inventory (MMPI) in patients with and without complications. 2 Surridge et at. reported that about one-quarter of a group of type I diabetic patients seemed sad or blue. but none met diagnostic criteria for major depression. 3 Friis and Nanjundappa investigated the relationship between unemployment and depression inventory scores in types I and II diabetes. 4 Diabetes was associated with both unemployment and elevated depression inventory scores; however. unemployment did not explain the elePSYCHOSOMATICS
Leedom et al.
vated depression inventory scores seen in diabetic patients. Lustman et al. utilized the Diagnostic Interview Scale (DIS) in order to determine the lifetime prevalence of psychiatric disorders in a group of 114 diabetic patients (57 type I, 57 type 11). 5 Lifetime prevalence rates for major depression and for dysthymic disorder were 36% and 17.5%, respectively, in the entire sample. Similarly, Popkin et al. utilized the same instrument to examine 75 type I diabetic patients with severe complications.6 The lifetime and 6month prevalence rates were 24% and 10.7% for major depression and 3% and 0% for dysthymic disorder. Since the vegetative symptoms of depression are similar to the somatic symptoms of diabetes mellitus, depression may be diagnosed (by self-report inventories or structured interview) in individuals who are not depressed. In an examination of this issue, Lustman et al. 5 excluded somatic symptoms from DIS diagnostic criteria and found very little effect of these symptoms on the observed prevalence of major depression and dysthymic disorder in diabetic patients. Although one well-designed study found a strong association between diabetic control and symptoms of depression and anxiety, 7 two other studies did not confirm these results. 2•B The complications of diabetes include, among other conditions, progressive blindness, renal failure, and chronic pain. It is expected that patients with such complications would be likely to experience symptoms of depression. Murawski et al. found that MMPI-Depression Scale scores were equally elevated in diabetic patients with and without complications. 2 Geringer et al. studied a group of 64 type II diabetic women. 9 A significant relationship was found between the degree of neuropathy and the degree of depression in those patients whose Zung Self-Rated Depression Scale (Zung SDS) scores were within the range of clinical depression. Turkington reported that pharmacological treatment of depression in patients with painful diabetic neuropathy resulted in resolution of both pain and depression. 1O To summarize, recent studies have indicated VOLUME 32· NUMBER 3· SUMMER 1991
a possible relationship between diabetic complications and symptoms of depression, as well as between diabetic control and symptoms of depression. Considering that the basic pathophysiologic mechanisms for metabolic control may be different in type I and type II diabetes, it may be important to study psychiatric symptoms in these two patient populations separately. The purpose of the present study was to examine symptoms of depression in patients with type II diabetes mellitus and to determine the prevalence of these symptoms. We chose to restrict our study to type II diabetic patients (noninsulin-dependent) because this group represents 80% of patients with diabetes mellitus. Symptoms of depression in patients with diabetic complications were compared to those in patients without complications and normal control subjects. Symptoms of sexual dysfunction were assessed and related to symptoms of depression and the presence of other diabetic complications. METHODS Subjects Type II diabetic subjects included 113 consecutive English-speaking patients from the outpatient diabetes clinic at LAC/USC Medical Center. All patients had random plasma glucose less than 300 mg/dl at the time of the study, and none had symptomatic hypoglycemia. All were between the ages of 30 and 70. Patients were told that as part of a study of mood changes and sexuality in diabetes, their medical histories would be reviewed; they would fill out questionnaires and undergo physical examination. Of the initial 113 patients, 26 refused to participate; 9 were excluded because of intercurrent illness (stroke n=3, lupus erythematosus n= I, hypothyroidism n=3, sarcoidosis n=l, and lymphoma n= I); 5 were excluded because of psychosis, and 2 because of alcoholism. Overall, the pool of 41 subjects who refused or who were excluded did not differ significantly in demographic characteristics from the 71 patients who participated in the study. Normal control subjects included 46 consec281
Depression and Type II Diabetes Mellitus
utive nonmedically ill visitors in the waiting area of the clinic. These subjects were told they were acting as a comparison group in a study of moods and sexuality in patients with diabetes. The control subjects were 31 women and 13 men with an average age of 46±1.7 (mean±SEM) years. There were 4 Asians. 21 blacks. II Caucasians. and 10 Hispanics. The diabetic patients were 50 women and 21 men with an average age of 50±2.0 years. There were 2 Asians. 28 blacks, 13 Caucasians, and 28 Hispanics. Fifty percent of the control subjects and 28% of the diabetic subjects were employed (X~=9.52. p
.f c
o
(j, (/)
Q)
Q
10
Q)
o
::(
U
Q)
m
FIGURE 2.
o
L . -_ _L . -
_
Zun\t Self·Rated Depression Scale (Zung SOSI scores for control subjects. diabetic patients without complications. and diabetic patients with complications. 80th groups of diabetic patients scored signilicantl}' higher than controls on the Zung SOS (·,,
