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Lifetime prevalence of specific psychiatric disorders in a general medicine clinic
Lifetime Prevalence of Specific Psychiatric Disorders in a General Medicine Clinic Takeshi Sato, M.D. and Masashi Takeichi, M.D.
Abstract: Using a two-stage case identification method, the Japanese version of the General Health Questionnaire CGHQJ and the Japanese modified Diagnostic Interview Schedule (DE-JM), patients in a general medicine clinic in Japan were assessed for psychiatric disorders (DSM-Ill categories) during a 12-month period. The lifetime prevalence of all psychiatric disorders was 30.6%, excluding tobacco dependence. The most prevalent diagnoses were alcohol abuse and dependence 9.4%, psychosexual dysfunction 5.9%, and major depressive episode 4.7%. The predominant disorders in males were alcohol abuse and dependence and tobacco dependence, and in females (aged 55-80 years), the most striking disorder was organic brain syndrome. The validity of the GHQ was examined against the DE-JM based on DSM-111 as external criteria. A cutoff point between 7 and 8 is suggested.
Introduction Recent epidemiologic studies in Western countries show that the prevalence of psychiatric disorders in primary care patients ranges from 15% to 36% based on structured assessment procedure 11-101. Though a careful assessment of primary care patients conducted by psychiatrists using standardized methods would be useful to establish the nature of psychiatric morbidity in primary care, a strict evaluation of the prevalence of psychiatric disorders in primary care practice in Japan has not yet been reported to our knowledge. In 1986, Saga Medical School was the first national medical school in Japan to establish a general medicine clinic for outpatient service. We can Department of Psychiatry, Saga Medical School, Saga, Japan. Address reprint requests to: Takeshi Sato, M.D., Department of Psychiatry, Saga Medical School, Nabeshima 5-l-1, Saga, Japan, 849.
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therefore provide epidemiologic data from psychiatric disorders in a Japanese primary care population, and compare cross-cultural differences in diagnosis using a similar methodology. The aim of this study was to investigate the lifetime prevalences of specific psychiatric disorders in patients attending the general medicine clinic. We used two methods of assessment: a Japanese version of the 30-item General Health Questionnaire (GHQ) 111,121, and a Japanese modification of the Diagnostic Interview Schedule (version III) (DIS-JM) 113-151. We estimated the lifetime prevalence of psychiatric disorders in primary care patients based on the Diagnostic and Statistical Manual, Third Edition (DSM-III). Using the lifetime frame, it is possible to compare Japanese psychiatric epidemiology with other epidemiologic studies that reported lifetime or period prevalence rates. We also examined the relationship of selected demographic variables to some specific disorders. The GHQ was evaluated as a clinical screening device for psychiatric disorders by calculating its sensitivity and specificity in terms of the DSM-III.
Methods This study was conducted in the general medicine clinic of the Saga Medical School Hospital (SMSH) in Saga City, Japan. The clinic handles approximately 32,000 patient visits annually. It is staffed by seven physicians affiliated with the general medicine clinic, who provide primary care rather is than specialized care. Its patient population drawn mainly from the small urban community surrounding the hospital. General Hospital Psychiatry 15, 224-233, 1993 1993 Elsevier Science Publishing Co., Inc. 655 Avenue of the Americas, New York, NY 10010 6
0163-8343/93/$6.00
Psychiatric Disorders in a General Medicine Clinic
Table 1. Random numbers Stratum January February March April May June
July
August September October November December Total
Study day (N)
Screened patients (N)
Interviewed patients (N)
8 8 8 8 8 8 9 8 8 6 8 7 94
113 110 110 100 86 89 96 106 77 74 67 55 1,083
15 16 16 16 11 14 18 15 13 11 14 11 170
“Mean sampling proportion
Sampling proportion (o/o) 13.3 14.5 14.5 16.0 12.8 15.7 18.8 14.2 16.9 14.9 20.9 20.0 16.0 (2.6)”
(SD).
The subjects of this study were patients 18 years old or over who visited the SMSH for the first time during the study period (January 1, 1991-December 31, 1991). To get a representative sample, we applied a subsampling method with units of unequal sizes (multistage random sampling) [16]. In the first stage, 2 study days were randomly chosen from Monday to Friday. On each study day, two patients were selected, also at random (Table 1). New patients were asked to fill out the forms for the Japanese version of the 30-item GHQ of Goldberg et al. [17] in the waiting room. The validity of the Japanese version of the 30-item GHQ’ was previously examined by Nakagawa and Daibo [ill and Kitamura et al. [12]. The standardized interviews (DIS-JM) were conducted during the first visit in a random sample of all GHQ-screened patients by a doctor (T.S.) with more than 5 years of clinical experience in a psychiatric setting. The doctor, legally registered as a psychiatric expert in mental health by the Ministry of Public Health and Welfare in Japan, interviewed patients without referring to the GHQ score. Before beginning the study, the interviewer received formal training in the use of the DIS and DSM-III at the Department of Psychiatry in the Fukuoka University School of Medicine (Prof. M. Nishizono). This highly structured diagnostic interview is widely used, and generates psychiatric diagnoses in conformity with DSM-III criteria. It ‘The Japanese version was retranslated into English by someone with no knowledge of the original English version.
produces most of the major Axis I diagnoses, both current and lifetime. The data are analyzed by computer [18]. Many studies have investigated the validity and reliability of the DIS [18-201. The validity and interrater reliability of the DIS-JM have already been evaluated by Nonaka et al. [13] and Nishizono et al. [151. Finally, DSM-III diagnoses were obtained using the IBM power station 320H, which analyzed scoring data with the Statistic Analysis System (SAS) software [211. In this study, the DIS-JM identified 18 specific psychiatric diagnoses. Though patients are hesitant to respond to the questions regarding sexuality, we did not omit the inquiries about transsexualism and ego-dystonic homosexuality from the interview. Data were analyzed by using the SAS (SAS Institute Japan Inc., 1991) [22]. The Mann-Whitney U test, Chi-square test, and Fisher’s exact test were applied.
Results Response Rate One thousand eighty-eight patients were given the screening questionnaire (GHQ). Five (0.5%) patients did not complete the questionnaire and were therefore excluded. Satisfactory screening data were obtained for 1,083 patients. One hundred seventy-two patients were randomly selected to undergo DIS-JM. Only two patients (1%) refused to participate in this structured interview. Thus, we 225
T. Sato and M. Takeichi
Table 2. Demographic
characteristic
Age, years Mean age (interquartile range) Sex Male Female Marital status Married Widowed Divorced/Separated Never married Education Elementary/ Junior high school High school Junior college/Special vocational school College/University Occupation Professional/Technical/ Administrative Sales, clerical Farmers/Fishermen Crafts people/Production Laborers Service workers/Maintenance Fulltime housewives Without occupation Miscellaneous
of patients completing
and diagnostic
interview
Interviewed (N = 170) n (%)
45.2 (18-88)
44.3 (21-80)
461 (42.6) 622 (57.4)
65 (38.2) 105 (61.8)
x’ = 1.1, df = 1 n.s.
763 67 29 224
128 11 5 26
(75.3) f 6.5) ( 2.9) (15.3)
x2 = 2.6, df = 3 n.s.
317 (29.3)
41 (24.1)
x2 = 2.5, df = 3 n.s.
445 (41.1) 183 (16.9)
79 (46.5) 27 (15.9)
138 (12.7)
23 (13.5)
211 (19.5)
31 (18.2)
198 94 59 47 86 180 153 55
32 22 8 8 7 31 20 11
(70.4) ( 6.2) ( 2.7) (20.7)
(18.3) ( 8.7) ( 5.4) ( 4.3) ( 7.9) (16.6) (14.1) ( 5.2)
ofthe Putients
Table 2 presents demographic data for all screened patients compared with those who completed a diagnostic interview. The mean age of the screened patients was 45.2 (range l&88), and that of the interviewed patients was 44.3 (range 21-80). A breakdown by gender reveals that 461 males and 622 females were included in the group of screened patients, and 65 males and 105 females were in the interviewed patients’ group. There was no significant difference between the screened group and interviewed group for age, sex, marital status, education, or occupation. It was shown that the patients interviewed were reason226
inventory
Screened (N = 1,083) n (o/o)
were able to conduct the DIS-JM with 170 patients (99%) during their first visit.
Characteristics
screening
P
n.s. (Mann-Whitney
U test)
x2 = 7.5, df = 8 n.s.
(18.8) (12.9) ( 4.7) ( 4.7) ( 4.1) (18.2) (11.8) ( 6.6)
ably representative of those screened, especially for patients of the general medicine clinic.
DE-JMIDSM-III Diagnosis Of the 170 patients interviewed, 65 (38.3%) were discovered to have had at least one psychiatric disorder at some time in their lives. Tobacco dependence was very frequent, but this is still not considered a true psychiatric illness in Japan. After exclusion of this disorder, the prevalence rate for exhibiting psychiatric disorders was 30.6%. The overall lifetime prevalences for the DIS-JM/DSMIII disorders covered in this study are shown in Table 3. The highest prevalence was related to alcohol abuse and dependence (9.4%). Psychosexual dysfunction and major depressive episodes had a prevalence of 5.9% and 4.7%, respectively. Phobias represented 3.5%, organic brain syndrome 2.9%,
Psychiatric Disorders in a General Medicine Clinic
Table 3. Lifetime prevalence
rates of DIS-III-TM /DSM-III disorders
Disorders
Overall (N = 170) n (o/o)
Any DIS disorder covered Any DIS disorder except tobacco dependence Organic brain syndrome Mania (bipolar) Major depressive episode Dysthymic disorder Alcohol abuse/dependence Drug abuse/dependence Schizophrenia Obsessive-compulsive disorder Phobias Somatization disorder Panic disorder Antisocial personality disorder Anorexia nervosa Tobacco dependence Pathological gambling Psychosexual dysfunction Transsexualism Egodystonic homosexuality
65 52 5 0 8 1 16 0 2 4 6 4 3 0 0 19 1 10 0 0
obsessive-compulsive disorder 2.4%, and somatization disorder 2.4%. All the rest had a prevalence of 2% or less.
Male/Female
Comparisons
Table 3 shows the relationship between lifetime prevalences and gender. For males, the most prevalent disorders were tobacco dependence (20.0%), alcohol abuse and dependence (l&5%), phobias (4.6%), and psychosexual dysfunction (6.7%). For females, the most prevalent disorders were psychosexual dysfunction (6.7%), major depressive episode (5.7%), tobacco dependence (5.7%), and organic brain syndrome (4.8%). Alcohol abuse and dependence and tobacco dependence rates were significantly higher for males than for females (p < 0.005 for alcohol abuse and dependence, p < 0.01 for tobacco dependence, using Fisher’s exact test).
Age Differences Table 4 shows the relationship between lifetime prevalence and age. The pattern of the highest lifetime rate occurred in the 35 to 54-year-old group. This rate did not differ significantly from those of
(38.3) (30.6) ( 2.9) ( 0.0) ( 4.7) ( 0.6) ( 9.4) ( 0.0) ( 1.2) ( 2.4) ( 3.51 ( 2.4) ( 1.8) ( 0.0) ( 0.0) (11.2) ( 0.6) ( 5.9) ( 0.0) ( 0.0)
Males (N = 65) n (%I 32 22 0 0 2 1 12 0 2 1 3 2 1 0 0 13 1 3 0 0
(49.2) (37.8) ( 0.0) ( 0.0) ( 3.1) ( 1.5) (18.5) ( 0.0) ( 3.1) ( 1.5) ( 4.6) ( 3.1) ( 1.5) ( 0.0) ( 0.0) (20.0) ( 1.5) ( 4.6) ( 0.0) ( 0.0)
Females (N = 105)
n (%) 33 30 5 0 6 0 4 0 0 3 3 2 2 0 0 6 0 7 0 0
(31.4) (28.6) ( 4.8) ( 0.0) ( 5.7) ( 0.0) ( 3.8) ( 0.0) ( 0.0) ( 2.9) ( 2.9) ( 1.9) ( 1.9) ( 0.0) ( 0.0) ( 5.71 f 0.0) ( 6.7) ( 0.0) ( 0.0)
P CO.05 n.s. ns. n.s. n.s. ns. CO.005 n.s. n.s. ns. n.s. ns. n.s. ns. n.s. CO.01 n.s. n.s. n.s. n.s.
the two other groups, however. The 18 to 34-yearold group exceeded the above group with respect to alcohol abuse and dependence and somatization disorder, and the 35 to 54-year-old group had the highest frequency of major depressive episode and tobacco dependence. The 55 to 80-year-old group had the highest rate of organic brain syndrome. This difference was statistically significant compared with the younger groups (p < 0.005, using Fisher’s exact test).
Screening Performance the GHQ
of the Japanese Version of
Table 5 shows the screening performance of the Japanese version of the GHQ with different cutoff points. Sensitivity is the proportion of “cases” correctly identified by the higher GHQ score to the true “cases.“ Specificity is the proportion of “noncases” correctly identified by the lower GHQ score to the true “non-cases,” and the positive predictive value is the proportion of “cases” among those with higher GHQ scores. The overall misclassification rate is the proportion of those erroneously identified. Twelve patients with tobacco dependence were 227
T. Sato and M. Takeichi
Table 4. Lifetime prevalence
rates of DIS-III-JM/DSM-III
disorders
18-34 years
for three age groups 55-80 years (N = 48)
(N = 53)
35-54 years (N = 69)
n (%)
n (%)
Mean age (S.D.)
28.1 (4.2)
42.7 (5.5)
64.7 (7.2)
Any DIS disorder covered Any DIS disorder except tobacco dependence Organic brain syndrome Mania (bipolar) Major depressive episode Dysthymic disorder Alcohol abuse/ dependence Drug abuse/ dependence Schizophrenia Obsessive-compulsive disorder Phobias Somatization disorder Panic disorder Antisocial personality disorder Anorexia nervosa Tobacco dependence Pathological gambling Psychosexual dysfunction Transsexualism Egodystonic homosexuality
20 18 0 0 1 0 7 0 2 2 2 2 1 0 0 4 0 5 0 0
27 18 0 0 5 1 6 0 0 1 3 2 1 0 0 11 1 2 0 0
18 16 5 0 2 0 3 0 0 1 1 0 1 0 0 4 0 3 0 0
Disorders
excluded from the study. For the seven patients who combined tobacco dependence with other psychiatric disorders, we considered the other disorders only. As can be seen, the cutoff point of 4/5 originally recommended by Goldberg 1231 produced a relatively high sensitivity (88.9%), but did not appear appropriate in terms of specificity (47.8%) and the overall misclassification rate (45.4%). It is known that specificity and sensitivity ideally are above 70%. We estimate that a cutoff point of between 7 and 8 is recommendable, giving an increased specificity of 66.9% and a decreased overall misclassification rate of 34.7%.
Discussion Psychiatric Disorders in Primary Care Practice and Community A review of the pertinent studies 1241 indicates that psychiatric morbidity rates in primary care still differ markedly, ranging from 11% to 36%. The result of this study on the lifetime prevalence of the specific disorders defined by the DSM-III criteria was 228
(37.7) (34.0) ( 0.0) ( 0.0) ( 1.9) ( 0.0) (13.2) ( 0.0) ( 3.8) ( 3.8) ( 3.8) ( 3.8) ( 1.9) ( 0.0) ( 0.0) ( 7.5) ( 0.0) ( 9.4) ( 0.0) ( 0.0)
(39.1) (26.1) ( 0.0) ( 0.0) ( 7.2) ( 1.4) ( 8.7) ( 0.0) ( 0.0) ( 1.4) ( 4.3) ( 2.9) ( 1.4) ( 0.0) ( 0.0) (15.9) ( 1.4) ( 2.8) ( 0.0) ( 0.0)
n (o/o)
(37.5) (33.3) (10.4) ( 0.0) ( 4.2) ( 0.0) ( 6.3) ( 0.0) ( 0.0) ( 2.1) ( 2.1) ( 0.0) ( 2.1) ( 0.0) ( 0.0) ( 8.3) ( 0.0) ( 6.3) ( 0.0) ( 0.0)
P
n.s. n.s. CO.005 n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. ns. n.s.
30.6%, excluding tobacco dependence. With regard to the psychiatric prevalence rate in general, our findings were consistent with those obtained by the four earlier studies that examined rates for specific disorders in primary care settings using structured diagnostic interviews [1,6,9,101. However, our results cannot be precisely compared with these reports because these prior epidemiologic rates are based on period prevalence and there are differences in instruments and diagnostic criteria. Although it is important to recognize that the prevalence rates differ according to the time period employed for measurement, we made a general comparison with previous studies. Furthermore, we compared our lifetime prevalences with those of communities in the U.S. Another comparison was made with lifetime prevalence of community and inpatients in Japan. The study of Hoeper et al. 111 in Mansfield, Ohio has a similar methodology. They used the GHQ as a screening instrument, followed by a Schedule for Affective Disorder and Schizophrenia [SADS] interview to obtain the Research Diagnostic Criteria [RDCI for the diagnoses. The prevalence rate of RDC mental disorder for the adult primary care
Psychiatric Disorders in a General Medicine Clinic
Table 5. Validity of the Japanese
GHQ
version of the GHQ for different cutoff points
scores
Sensitivity t%)
Specificity (%)
Positive predictive value (%)
Negative predictive value (%)
2/3 3/4 4/5 5/6 6/7 7/8 8/9 9/10 10/11 11/12 12/13 13/14
86.5 84.6 73.6 73.6 65.4 61.5 48.1 44.2 44.2 42.3 42.3 40.4
30.5 39.8 46.2 53.0 60.2 66.9 71.2 78.0 82.2 83.1 88.1 89.8
35.4 38.3 38.2 41.5 42.0 45.1 42.4 46.9 52.3 52.4 61.1 63.6
83.7 85.5 79.4 81.6 79.8 79.8 75.7 76.0 77.0 76.6 77.6 77.4
Overall misclassification
(%)
52.4 46.5 45.3 40.6 38.2 34.7 35.9 32.4 29.4 29.4 25.9 25.3
Taking off patients in one diagnostic category of tobacco dependence.
patient population was 26.7%. The rate of major depression (DSM-III) reached 5.8%, somewhat consistent with ours. Schulberg et al. [6] used a two-stage case identification method: a self-report screening (the Center for Epidemiological Studies Depression Scale) and DIS interview on a sample of patients from three primary medical care centers. Using current DIS/DSM-III diagnoses, the prevalence rate of all disorders was 31.3%, excluding tobacco dependence and psychosexual dysfunction. Among the patients who participated in the DIS interview, the proportion of patients considered as having depressive disorders was 9.2%. Frequent diagnoses were alcohol abuse (8.2%), substance abuse (5.8%), and antisocial personality (5.8%). The lifetime prevalence of alcohol abuse and dependence in our study was 9.4%. This rate was slightly higher than that found by Schulberg et al. 161. This difference might be due to the lifetime prevalence measure in the current study. However, our prevalences of drug abuse and dependence and antisocial personality were notably lower than theirs. Nishioka et al. [14] reported a low rate of drug abuse and dependence (0%) and antisocial personality (1 .O%) among internal medicine and orthopedic patients in Japan, based on the lifetime prevalence using the DIS-JM interview. This phenomenon was also observed in the Taiwanese community population 1251. It seems
apparent
that the urban
population
in the U.S. is quite different in other ways, even though this study was not carried out in a primary care practice in a large Japanese metropolitan population. Honda 1261 pointed out that the type of
personality disorders described in DSM-III were unfamiliar to Japanese psychiatrists. Another reason is that several cultural-specific factors may contribute significantly to the low prevalence rates of drug abuse and dependence and antisocial personality in Japanese primary care. Von Korff et al. [9] examined an inner-city clinic in Baltimore using the GHQ for the initial screening and the DIS interview to establish a psychiatric diagnosis. The DIS/DSM-III diagnostic rates for specific depressive disorders were 5.0% for major depression and 3.7% for dysthymia. Though the rate for alcohol abuse and dependence was 5.0%, the overall rate for all disorders assessed by the DIS interview was 25.0%. Our report shows conformity with regard to major depression. Barrett et al. [lo] assessed patients from a rural primary care practice for all psychiatric disorders (RDC categories) and found the prevalence to be 26.5%. RDC depressive disorders represented 10.0% of the total, and the anxiety-related disorders, 5.3%. According to the above reports based on period prevalence, there was considerable consistency in the rates of all psychiatric disorders twenty-five percent to 30% of primary care patients were found to have some psychiatric disorders. This suggests that the most common psychiatric disorders observed in primary care practice are alcohol abuse and dependence, and depression. These diagnoses are in part similar to the epidemiologic reports from three U.S. urban communities (Baltimore, St. Louis, and New Haven, Connecticut) surveyed by the Epidemiologic Catchment Area (ECA) study, based on lifetime preva229
T. Sato and M. Takeichi
lence using the DIS interview 127,281. These trends were also noted at Durham, Los Angeles 129-311, and Puerto Rico 1321. Regarding depression, Robins et al. [27] reported that the lifetime prevalence of major depressive episodes ranged from 3.7% to 6.7% from the three sites of the ECA study, whereas a prevalence rate of 6.0% for the Japanese general population in Ichikawa city 1331 and a 6.5% prevalence rate was found among internal medicine and orthopedic inpatients in Japan 1141. Generally, compared with the community population, the population of adult primary care patients has a disproportionately high concentration of patients with mental disorders Ill. According to Schulberg et al. 161, Von Korff et al. 191, and Barrett et al. 1101, the period prevalence of depression among the primary care population using the structured assessment procedure was 9.2%, 8.7%, and lO.O%, respectively. A rate of 4.7% for lifetime prevalence of major depressive episode obtained in this study was lower than that of the general population (6.0%) and inpatients (6.5%) in Japan 114,331. However, with regard to somatization disorder, the lifetime prevalence of primary care patients (2.4%) showed a disproportionately high concentration compared with the general population (1.0%) in Japan 1331; this suggests that patients with somatization disorder are relatively rare in the community but are associated with higher rates of seeking health care in primary care settings, compared with major depressive episode in Japan. On the other hand, one point of interest is the lower rate of “all depressives” in comparison with previous reports on U.S. primary care patients [6,9,101. Kleinman [341 stated that from the crosscultural standpoint, “the somatic idiom for expressing depressive feeling among Chinese constitutes that affect as a vegetative experience profoundly different from its intensely personal, existential quality among middle-class Americans,” Similarly, Marsella 1351 showed that “among the Japanese the same effect is communicated in an external, naturalistic metaphor-clouds, rain, mistthat again appears to produce a distinct difference in the quality of the experience of depressive effect.” This cultural background might explain the lack of Japanese study sample responses to the symptom questions for depression in the DIS interview. However, it is likely that the major influence of illness behavior theory and classification has been in relation to disorders presenting with functional symptoms as, for instance, somatoform disorder and the Axis V category, “Noncompliance 230
with Medical Treatment” J361. In recent studies of Katon et al. 137-391 and Von Korff et al. 1401, somatic idioms of distress in the U.S. have been discussed, and several mechanisms that explain the association between mental illness and medically unexplained somatic symptoms have been reported by analyzing the characteristics of distressed high utilizers of medical care. Somatization has been described as the presentation of psychosocial distress in an idiom of physical symptom J41-431. Our clinical data cannot shed light on the mechanisms linking psychological disorders and somatic complaints. With regard to the problem of misdiagnosis of depression in general medical settings, Katon [441 has questioned whether the clinical syndromes are the same or different in psychiatric patients who are depressed. Williamson and William 1451 have pointed out that patients presenting with depression in a general medical setting tend to be in an earlier, milder, and “unorganized” stage of the illness compared with those in a psychiatric speciality setting. Medical patients are less psychologically experienced and less sophisticated in their ability to describe their symptoms. These findings as well as cultural influences upon the way depression is experienced in Japan may further explain the relationship between somatic complaints and depression. Understanding the changes in somatic complaints during the course of depression may help researchers further define the relationship between depression and somatization 1461. In addition to the prevalence rate, we determined the relationship of the demographic variables to the specific disorders in the primary care setting. According to Robins et al. [27], in a community sample based on the lifetime prevalence of DIS interview, the clearly predominant disorders in males were antisocial personality and alcohol abuse and dependence. But among females, depressive episodes and phobia prevailed. In this study, our observations correspond to Robins’s, with the exception of the antisocial personality and phobic disorders. The striking finding of this study is that the organic brain syndrome (e.g., dementia) appears most frequently in the female group aged 55-80 years. We think the increase in this organic brain syndrome prevalence is the reflection of the aging of the Japanese population, especially Japanese females, who have a life-span of 82.1 years, the longest in the world 1471. In general, primary care providers are likely to play an important role in any improvement of the
Psychiatric Disorders in a General Medicine Clinic
detection and treatment
of mental disorders. There is now growing evidence that more than half of all patients receiving treatment for mental disorders receive care from primary care physicians only. Of those people with depressive symptoms who seek medical care, 80% are evaluated by primary care physicians, and only 20% consult mental health specialists, of which 50% are psychiatrists 148501. Thus, we should provide educational training for depression, alcohol abuse and dependence, and organic brain syndrome to primary care physicians to improve the sensitivity of screening in the Japanese primary care population.
Validity of the Japanese Version of the GHQ among Primary Care Patients Prior to the present investigation, two studies examined the validity of the GHQ in Japan. In the first study, Nakagawa and Daibo [ill distributed the 60-item GHQ to two groups of subjects: normal volunteers whose mental state had been confirmed to be nonpsychiatric by the Present State Examination interview, and psychiatric patients known by the investigators. This study found the cutoff point of 14/15 for the 60-item GHQ to be the most discriminating for the Japanese population. In the second study, Kitamura et al. 1121 examined the validity of the GHQ using the semistructured interview based on RDC as external criteria among antenatal clinic patients. The recommended cutoff point was 7/8, taking into account the resulting balance of sensitivity (88.9%) and specificity (71.1%). The result of the current study using the DIS interview as external criteria suggests an optimum threshoid score of 7/8. This cutting score is associated with a specificity of 66.9% and an overall misclassification rate of 34.7%. It is regrettable, however, that specificity and sensitivity were not above 70%. It is difficult to extrapolate these results to the other studies because the sensitivity and specificity depend on the proportion of the screened populations with positive results for a given screening method. Cleary et al. [511 showed that the resultant sensitivity of the 30-item GHQ is 7S%, and the specificity is 85% in the Wisconsin study using the SADS-lifetime interview as external criteria. Another explanation for the low sensitivity and specificity in this sample is that “caseness” was defined using the lifetime DIS diagnoses. The GHQ screens for current symptoms and, except in the
case of presumably chronic or unremitting disorders, it is not surprising that GHQ current results may not be sensitive or specific to lifetime DSM-III disorders. Thus, the GHQ should be better at predicting the current “caseness” on structured psychiatric interviews. In conclusion, the results of this study present more problems than solutions concerning the psychiatric care of primary care patients. Further Japanese epidemiologic studies in primary care are needed to examine the prevalence of psychiatric illness and screening scales to better detect this illness. Of special interest, because of this high prevalence, will be the recognition and treatment of aIcoho1 abuse and dependence, major depressive episode, and organic brain syndrome by the primary care physicians in Japan. We would like to thnnk Prof. M. Nishizono of fhe Psychiatry Department, School of Medicine in Fukuoka University for giving us the opportunity of training in the DIS interview. We also thank Prof. M. Nishizumi of the Community Health Science Department of Saga Medical School for advice in the epidemiology, as well as Dr. H. Nakao, former president of Saga Medical School Hospital, and Prof. T. Fukui of the Department of General Medicine Clinic, Saga Medical Srkoot, for their cunfinuous guidance and encouragement in this study.
References 1. Hoeper EW, Nycz GR, Cleary PD, Regier DA, Gold-
berg ID: Estimated prevalence of RDC mental disorder in primary medical care. Int J Ment Health 8: 6--15,1979 2. Cooper B: Psychiatric illness in general medical prac-
3.
4. 5.
6.
7.
8.
9.
tice. An investigation in Mannheim. Int J Rehabil Res 4:86-88, 1981 Hough R, Landsverk J, Stone J, et al: Comparison of psychiatric screening questionnaires for primary care patients. Report on contract 278-81-0036 (DB). Rockville, MD, National Institute of Mental Health, 1983 Hoeper E, Nycz G, Kessler L, et al: The usefullness of screening for mental illness. Lancet i:33-35, 1984 Skuse D, Williams P: Screening for psychiatric disorder in general practice. Psycho1 Med 14:365-377, 1984 Schulberg HC, Saul M, McClelland M, et al: Assessing depression in primary medical and psychiatric practices. Arch Gen Psychiatry 42:1164-1170, 1985 Bellantuono C, Fiorio R, Williams P, et al: Psychiatric morbidity in an Italian general practice. Psycho1 Med 17243-247, 1987 Kessler L, Burns B, Shapiro S, Tischler G, et al: I’sychiatric diagnoses of medical service users: evidence from the Epidemiologic Catchment Area Program. Am J Pub Health 77:18-24, 1987 Von Korff M, Shapiro S, Burke JD, et al: Anxiety and
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depression in a primary care clinic. Arch Gen I’sychiatry 44:152-156, 1987 10. Barrett JE, Barrett JA, Oxman TE, Gerber I’D: The prevalence of psychiatric disorders in a primary care practice. Arch Gen Psychiatry 45:1100-1106, 1988 11. Nakagawa Y, Daibo I: Validity and reliability of the Japanese version of the General Health Questionnaire and its clinical application. National Institute of Mental Health, Japan, 1981 (in Japanese) 12. Kitamura T, Sugawara M, Aoki M, Shima S: Validity of the Japanese version of the GHQ among antenatal clinic attendants. Psycho1 Med 19:507-511, 1989 13. Nonaka Y, Nishizono M, Yamamoto J: Neurosis from the viewpoint of DIS (Diagnostic Interview Schedule). Jpn J Psychiatr Neurol 43:591-618, 1989 14. Nishioka Y, Nishizono M, Yamamot J: The distribution of mental illness found by DIS (Diagnostic Interview Schedule) among internal and orthopedic patients. Jpn J Psychiatr Neurol 44:33-54, 1990 15. Nishizono M, Nagamoto A, Yamamoto J, Nanaka Y: Concordance rate between clinical and DIS diagnoses: a cross-cultural comparison. Jpn J Psychiatr Neurol45:577-581, 1991 16. Cochran WG: Sampling Techniques, 3rd ed. New York, John Wiley & Sons, 1977 17. Goldberg D, Rickels K, Downing R, et al: A comparison of two psychiatric screening tests. Br J Psychiatry 129:61-67, 1976 18. Robins LN, Helzer JE, Croughan J, Ratcliff KS: National Institute of Mental Health Diagnostic Interview: its history, characteristic, and validity. Arch Gen Psychiatry 38:381-389, 1981 19. Robins LN, Helzer JE, Ratcliff KS, Seyfried W: Validity of the Diagnostic Interview Schedule, Version II: DSM-III diagnoses. Psycho1 Med 12:855-870, 1982 20. Helzer JE, Robins LN, McEvory LT, et al: A comparison of clinical and diagnostic interview schedule diagnoses. Arch Gen Psychiatry 42:657-666,1985 21. SAS Institute Inc: SAS companion for the UNIX environment and derivatives. North Carolina, SAS Institute Inc., 1990 22. SAS Institute Inc: SAS/STAT User’s Guide. North Carolina, SAS Institute Inc., 1990 23. Goldberg D: The Detection of Psychiatric Illness by Questionnaire: A Technique for the Identification and Assessment of Non-psychotic Illness (Maudsley monographs, No.21). London, Oxford University Press, 1972 24. Schulberg HC, Burns BJ: Mental disorders in primary care: epidemiologic, diagnostic, and treatment research directions. Gen Hosp Psychiatry 10:79-87, 1988 25. Hwu HG, Yeh EK, Chang LY: Prevalence of psychiatric disorders in Taiwan defined by the Chinese Diagnostic Interview Schedule. Acta Psychiatr Stand 79:136-147, 1989 26. Honda Y: DSM-III Japan. In Spitzer RL, Williams JBW, Skodol AE feds), International Perspectives on DSM-III. Washington, American Psychiatric Press, Inc., 1983, pp. 185-201 27. Robins LN, Helzer JE, Weissman MM, et al: Lifetime prevalence of specific psychiatric disorders in three sites. Arch Gen Psychiatry 41:949-958, 1984
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28. Myers JK, Weissman MM, Tischler GL, et al: Sixmonth prevalence of psychiatric disorders in three communities 1980 to 1982. Arch Gen Psychiatry 41: 959-967, 1984 29. Burnam MA, Hough RL, Escobar JI, et al: Six-month prevalence of specific psychiatric disorders among Mexican Americans and non-Hispanic whites in Los Angeles. Arch Gen Psychiatry 44:687-694, 1987 30. Karno M, Hough RL, Burnam MA, et al: Lifetime prevalence of specific psychiatric disorders among Mexican Americans and non-Hispanic whites in Los Angeles. Arch Gen Psychiatry 44:695-701, 1987 31. Regier DA, Boyd JH, Burke JD, et al: One-month prevalence of mental disorders in the United States: based on five epidemiologic catchment area sites. Arch Gen Psychiatry 45:977-986, 1988 32. Canino GJ, Bird HR, Shrout PE, et al: The prevalence of specific psychiatric disorder in Puerto Rico. Arch Gen Psychiatry 44~727-735, 1987 33. Machizawa S: A comparison of the alcohol abuse and dependence prevalence in Asian countries and the US. The 4th Scientific Meeting of the Pacific Rim College of Psychiatrist, Hong Kong, 1988 34. Kleinman A: Patients and Healers in the Context of Culture. Berkeley, University of California Press, 1980 35. Marsella AJ: Depressive experience and disorder across cultures. In Triandis H, Draguns J (eds), Handbook of Cross-Cultural Psychology, Vo15: Culture and Psychopathology. Boston, Allyn and Bacon, 1977, pp. 30-72 36. Mayou R: Illness behavior and psychiatry. Gen Hosp Psychiatry 11:307-312, 1989 37. Katon W, Von Korff M, Lin E, et al: Distressed high utilizers of medical care- DSM-III-R diagnoses and treatment needs. Gen Hosp Psychiatry 12:355-362, 1990 38. Katon W, Lin E, Von Korff M, Russo J, Lipscomb P, Bush T: Somatization: a spectrum of severity. Am J Psychiatry 148:3&O, 1991 39. Katon W, Von Korff M, Lin E, et al: A randomized trial of psychiatric consultation with distressed high utilizers. Gen Hosp Psychiatry 14:86-98, 1992 40. Von Korff M, Ormel J, Katon W, Lin EHB: Disability and depression among high utilizers of health care. Arch Gen Psychiatry 49:91-100, 1992 41. Katon W, Kleinman A, Rosen G: Depression and somatization. A review. Am J Med 72:127-135,241-247, 1982 42. Katon W: Panic disorder: epidemiology, diagnosis and treatment in primary care. J Clin Psychiatry 47(Suppl):21-27, 1986 43. Barsky AJ, Klerman GL: Overview: hypochondriasis, bodily complaints, and somatic styles. Am J Psychiatry 140:273-283, 1983 44. Katon W: Deuression: somatic svmutoms and medical disorders’in primary care. Cbm’pr Psychiatry 23: 274-287.1982 45. Williamson I’, William RY: The initial presentation of depression in family practice and psychiatric outpatients. Gen Hosp Psychiatry 11:188-193, 1989 46. Sato T, Sakihata H, Takeichi M: Studies on general medicine clinic psychiatry: a comparison of 30-item
Psychiatric Disorders in a General Medicine Clinic
General Health Questionnaire results between general medicine clinic and psychiatric clinic depressive patients treated with sulpiride. Kyushu N-psych 37: 240-246, 1991 (in Japanese) 47. Health and Welfare Statistics Association: life table. J Health Welfare Statistics (Suppl) 39:72-79, 1992 (in Japanese) 48. Weissman MM, Myers JK: Rates and risks of depressive symptoms in a United States urban community. Acta Psychiatr Stand 57219-231, 1978
49. Regier DA, Goldber ID, Taube CA: The de facto US mental health services system. Arch Gen Psychiatry 35:685-693, 1978 50. Schurman RA, Kramer I’D, Mitchell JB: The hidden mental health network: treatment of mental illness by nonpsychiatrist physicians. Arch Gen Psychiatry 42: 89-94, 1985 51. Cleary I’D, Goldberg ID, Kessler LG, Nycz GR: Screening for mental disorder among primary care patients. Arch Gen Psychiatry 39:837-840, 1982
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Abstract: Using a two-stage case identification method, the Japanese version of the General Health Questionnaire CGHQJ and the Japanese modified Diagnostic Interview Schedule (DE-JM), patients in a general medicine clinic in Japan were assessed for psychiatric disorders (DSM-Ill categories) during a 12-month period. The lifetime prevalence of all psychiatric disorders was 30.6%, excluding tobacco dependence. The most prevalent diagnoses were alcohol abuse and dependence 9.4%, psychosexual dysfunction 5.9%, and major depressive episode 4.7%. The predominant disorders in males were alcohol abuse and dependence and tobacco dependence, and in females (aged 55-80 years), the most striking disorder was organic brain syndrome. The validity of the GHQ was examined against the DE-JM based on DSM-111 as external criteria. A cutoff point between 7 and 8 is suggested.
Introduction Recent epidemiologic studies in Western countries show that the prevalence of psychiatric disorders in primary care patients ranges from 15% to 36% based on structured assessment procedure 11-101. Though a careful assessment of primary care patients conducted by psychiatrists using standardized methods would be useful to establish the nature of psychiatric morbidity in primary care, a strict evaluation of the prevalence of psychiatric disorders in primary care practice in Japan has not yet been reported to our knowledge. In 1986, Saga Medical School was the first national medical school in Japan to establish a general medicine clinic for outpatient service. We can Department of Psychiatry, Saga Medical School, Saga, Japan. Address reprint requests to: Takeshi Sato, M.D., Department of Psychiatry, Saga Medical School, Nabeshima 5-l-1, Saga, Japan, 849.
224 ISSN
therefore provide epidemiologic data from psychiatric disorders in a Japanese primary care population, and compare cross-cultural differences in diagnosis using a similar methodology. The aim of this study was to investigate the lifetime prevalences of specific psychiatric disorders in patients attending the general medicine clinic. We used two methods of assessment: a Japanese version of the 30-item General Health Questionnaire (GHQ) 111,121, and a Japanese modification of the Diagnostic Interview Schedule (version III) (DIS-JM) 113-151. We estimated the lifetime prevalence of psychiatric disorders in primary care patients based on the Diagnostic and Statistical Manual, Third Edition (DSM-III). Using the lifetime frame, it is possible to compare Japanese psychiatric epidemiology with other epidemiologic studies that reported lifetime or period prevalence rates. We also examined the relationship of selected demographic variables to some specific disorders. The GHQ was evaluated as a clinical screening device for psychiatric disorders by calculating its sensitivity and specificity in terms of the DSM-III.
Methods This study was conducted in the general medicine clinic of the Saga Medical School Hospital (SMSH) in Saga City, Japan. The clinic handles approximately 32,000 patient visits annually. It is staffed by seven physicians affiliated with the general medicine clinic, who provide primary care rather is than specialized care. Its patient population drawn mainly from the small urban community surrounding the hospital. General Hospital Psychiatry 15, 224-233, 1993 1993 Elsevier Science Publishing Co., Inc. 655 Avenue of the Americas, New York, NY 10010 6
0163-8343/93/$6.00
Psychiatric Disorders in a General Medicine Clinic
Table 1. Random numbers Stratum January February March April May June
July
August September October November December Total
Study day (N)
Screened patients (N)
Interviewed patients (N)
8 8 8 8 8 8 9 8 8 6 8 7 94
113 110 110 100 86 89 96 106 77 74 67 55 1,083
15 16 16 16 11 14 18 15 13 11 14 11 170
“Mean sampling proportion
Sampling proportion (o/o) 13.3 14.5 14.5 16.0 12.8 15.7 18.8 14.2 16.9 14.9 20.9 20.0 16.0 (2.6)”
(SD).
The subjects of this study were patients 18 years old or over who visited the SMSH for the first time during the study period (January 1, 1991-December 31, 1991). To get a representative sample, we applied a subsampling method with units of unequal sizes (multistage random sampling) [16]. In the first stage, 2 study days were randomly chosen from Monday to Friday. On each study day, two patients were selected, also at random (Table 1). New patients were asked to fill out the forms for the Japanese version of the 30-item GHQ of Goldberg et al. [17] in the waiting room. The validity of the Japanese version of the 30-item GHQ’ was previously examined by Nakagawa and Daibo [ill and Kitamura et al. [12]. The standardized interviews (DIS-JM) were conducted during the first visit in a random sample of all GHQ-screened patients by a doctor (T.S.) with more than 5 years of clinical experience in a psychiatric setting. The doctor, legally registered as a psychiatric expert in mental health by the Ministry of Public Health and Welfare in Japan, interviewed patients without referring to the GHQ score. Before beginning the study, the interviewer received formal training in the use of the DIS and DSM-III at the Department of Psychiatry in the Fukuoka University School of Medicine (Prof. M. Nishizono). This highly structured diagnostic interview is widely used, and generates psychiatric diagnoses in conformity with DSM-III criteria. It ‘The Japanese version was retranslated into English by someone with no knowledge of the original English version.
produces most of the major Axis I diagnoses, both current and lifetime. The data are analyzed by computer [18]. Many studies have investigated the validity and reliability of the DIS [18-201. The validity and interrater reliability of the DIS-JM have already been evaluated by Nonaka et al. [13] and Nishizono et al. [151. Finally, DSM-III diagnoses were obtained using the IBM power station 320H, which analyzed scoring data with the Statistic Analysis System (SAS) software [211. In this study, the DIS-JM identified 18 specific psychiatric diagnoses. Though patients are hesitant to respond to the questions regarding sexuality, we did not omit the inquiries about transsexualism and ego-dystonic homosexuality from the interview. Data were analyzed by using the SAS (SAS Institute Japan Inc., 1991) [22]. The Mann-Whitney U test, Chi-square test, and Fisher’s exact test were applied.
Results Response Rate One thousand eighty-eight patients were given the screening questionnaire (GHQ). Five (0.5%) patients did not complete the questionnaire and were therefore excluded. Satisfactory screening data were obtained for 1,083 patients. One hundred seventy-two patients were randomly selected to undergo DIS-JM. Only two patients (1%) refused to participate in this structured interview. Thus, we 225
T. Sato and M. Takeichi
Table 2. Demographic
characteristic
Age, years Mean age (interquartile range) Sex Male Female Marital status Married Widowed Divorced/Separated Never married Education Elementary/ Junior high school High school Junior college/Special vocational school College/University Occupation Professional/Technical/ Administrative Sales, clerical Farmers/Fishermen Crafts people/Production Laborers Service workers/Maintenance Fulltime housewives Without occupation Miscellaneous
of patients completing
and diagnostic
interview
Interviewed (N = 170) n (%)
45.2 (18-88)
44.3 (21-80)
461 (42.6) 622 (57.4)
65 (38.2) 105 (61.8)
x’ = 1.1, df = 1 n.s.
763 67 29 224
128 11 5 26
(75.3) f 6.5) ( 2.9) (15.3)
x2 = 2.6, df = 3 n.s.
317 (29.3)
41 (24.1)
x2 = 2.5, df = 3 n.s.
445 (41.1) 183 (16.9)
79 (46.5) 27 (15.9)
138 (12.7)
23 (13.5)
211 (19.5)
31 (18.2)
198 94 59 47 86 180 153 55
32 22 8 8 7 31 20 11
(70.4) ( 6.2) ( 2.7) (20.7)
(18.3) ( 8.7) ( 5.4) ( 4.3) ( 7.9) (16.6) (14.1) ( 5.2)
ofthe Putients
Table 2 presents demographic data for all screened patients compared with those who completed a diagnostic interview. The mean age of the screened patients was 45.2 (range l&88), and that of the interviewed patients was 44.3 (range 21-80). A breakdown by gender reveals that 461 males and 622 females were included in the group of screened patients, and 65 males and 105 females were in the interviewed patients’ group. There was no significant difference between the screened group and interviewed group for age, sex, marital status, education, or occupation. It was shown that the patients interviewed were reason226
inventory
Screened (N = 1,083) n (o/o)
were able to conduct the DIS-JM with 170 patients (99%) during their first visit.
Characteristics
screening
P
n.s. (Mann-Whitney
U test)
x2 = 7.5, df = 8 n.s.
(18.8) (12.9) ( 4.7) ( 4.7) ( 4.1) (18.2) (11.8) ( 6.6)
ably representative of those screened, especially for patients of the general medicine clinic.
DE-JMIDSM-III Diagnosis Of the 170 patients interviewed, 65 (38.3%) were discovered to have had at least one psychiatric disorder at some time in their lives. Tobacco dependence was very frequent, but this is still not considered a true psychiatric illness in Japan. After exclusion of this disorder, the prevalence rate for exhibiting psychiatric disorders was 30.6%. The overall lifetime prevalences for the DIS-JM/DSMIII disorders covered in this study are shown in Table 3. The highest prevalence was related to alcohol abuse and dependence (9.4%). Psychosexual dysfunction and major depressive episodes had a prevalence of 5.9% and 4.7%, respectively. Phobias represented 3.5%, organic brain syndrome 2.9%,
Psychiatric Disorders in a General Medicine Clinic
Table 3. Lifetime prevalence
rates of DIS-III-TM /DSM-III disorders
Disorders
Overall (N = 170) n (o/o)
Any DIS disorder covered Any DIS disorder except tobacco dependence Organic brain syndrome Mania (bipolar) Major depressive episode Dysthymic disorder Alcohol abuse/dependence Drug abuse/dependence Schizophrenia Obsessive-compulsive disorder Phobias Somatization disorder Panic disorder Antisocial personality disorder Anorexia nervosa Tobacco dependence Pathological gambling Psychosexual dysfunction Transsexualism Egodystonic homosexuality
65 52 5 0 8 1 16 0 2 4 6 4 3 0 0 19 1 10 0 0
obsessive-compulsive disorder 2.4%, and somatization disorder 2.4%. All the rest had a prevalence of 2% or less.
Male/Female
Comparisons
Table 3 shows the relationship between lifetime prevalences and gender. For males, the most prevalent disorders were tobacco dependence (20.0%), alcohol abuse and dependence (l&5%), phobias (4.6%), and psychosexual dysfunction (6.7%). For females, the most prevalent disorders were psychosexual dysfunction (6.7%), major depressive episode (5.7%), tobacco dependence (5.7%), and organic brain syndrome (4.8%). Alcohol abuse and dependence and tobacco dependence rates were significantly higher for males than for females (p < 0.005 for alcohol abuse and dependence, p < 0.01 for tobacco dependence, using Fisher’s exact test).
Age Differences Table 4 shows the relationship between lifetime prevalence and age. The pattern of the highest lifetime rate occurred in the 35 to 54-year-old group. This rate did not differ significantly from those of
(38.3) (30.6) ( 2.9) ( 0.0) ( 4.7) ( 0.6) ( 9.4) ( 0.0) ( 1.2) ( 2.4) ( 3.51 ( 2.4) ( 1.8) ( 0.0) ( 0.0) (11.2) ( 0.6) ( 5.9) ( 0.0) ( 0.0)
Males (N = 65) n (%I 32 22 0 0 2 1 12 0 2 1 3 2 1 0 0 13 1 3 0 0
(49.2) (37.8) ( 0.0) ( 0.0) ( 3.1) ( 1.5) (18.5) ( 0.0) ( 3.1) ( 1.5) ( 4.6) ( 3.1) ( 1.5) ( 0.0) ( 0.0) (20.0) ( 1.5) ( 4.6) ( 0.0) ( 0.0)
Females (N = 105)
n (%) 33 30 5 0 6 0 4 0 0 3 3 2 2 0 0 6 0 7 0 0
(31.4) (28.6) ( 4.8) ( 0.0) ( 5.7) ( 0.0) ( 3.8) ( 0.0) ( 0.0) ( 2.9) ( 2.9) ( 1.9) ( 1.9) ( 0.0) ( 0.0) ( 5.71 f 0.0) ( 6.7) ( 0.0) ( 0.0)
P CO.05 n.s. ns. n.s. n.s. ns. CO.005 n.s. n.s. ns. n.s. ns. n.s. ns. n.s. CO.01 n.s. n.s. n.s. n.s.
the two other groups, however. The 18 to 34-yearold group exceeded the above group with respect to alcohol abuse and dependence and somatization disorder, and the 35 to 54-year-old group had the highest frequency of major depressive episode and tobacco dependence. The 55 to 80-year-old group had the highest rate of organic brain syndrome. This difference was statistically significant compared with the younger groups (p < 0.005, using Fisher’s exact test).
Screening Performance the GHQ
of the Japanese Version of
Table 5 shows the screening performance of the Japanese version of the GHQ with different cutoff points. Sensitivity is the proportion of “cases” correctly identified by the higher GHQ score to the true “cases.“ Specificity is the proportion of “noncases” correctly identified by the lower GHQ score to the true “non-cases,” and the positive predictive value is the proportion of “cases” among those with higher GHQ scores. The overall misclassification rate is the proportion of those erroneously identified. Twelve patients with tobacco dependence were 227
T. Sato and M. Takeichi
Table 4. Lifetime prevalence
rates of DIS-III-JM/DSM-III
disorders
18-34 years
for three age groups 55-80 years (N = 48)
(N = 53)
35-54 years (N = 69)
n (%)
n (%)
Mean age (S.D.)
28.1 (4.2)
42.7 (5.5)
64.7 (7.2)
Any DIS disorder covered Any DIS disorder except tobacco dependence Organic brain syndrome Mania (bipolar) Major depressive episode Dysthymic disorder Alcohol abuse/ dependence Drug abuse/ dependence Schizophrenia Obsessive-compulsive disorder Phobias Somatization disorder Panic disorder Antisocial personality disorder Anorexia nervosa Tobacco dependence Pathological gambling Psychosexual dysfunction Transsexualism Egodystonic homosexuality
20 18 0 0 1 0 7 0 2 2 2 2 1 0 0 4 0 5 0 0
27 18 0 0 5 1 6 0 0 1 3 2 1 0 0 11 1 2 0 0
18 16 5 0 2 0 3 0 0 1 1 0 1 0 0 4 0 3 0 0
Disorders
excluded from the study. For the seven patients who combined tobacco dependence with other psychiatric disorders, we considered the other disorders only. As can be seen, the cutoff point of 4/5 originally recommended by Goldberg 1231 produced a relatively high sensitivity (88.9%), but did not appear appropriate in terms of specificity (47.8%) and the overall misclassification rate (45.4%). It is known that specificity and sensitivity ideally are above 70%. We estimate that a cutoff point of between 7 and 8 is recommendable, giving an increased specificity of 66.9% and a decreased overall misclassification rate of 34.7%.
Discussion Psychiatric Disorders in Primary Care Practice and Community A review of the pertinent studies 1241 indicates that psychiatric morbidity rates in primary care still differ markedly, ranging from 11% to 36%. The result of this study on the lifetime prevalence of the specific disorders defined by the DSM-III criteria was 228
(37.7) (34.0) ( 0.0) ( 0.0) ( 1.9) ( 0.0) (13.2) ( 0.0) ( 3.8) ( 3.8) ( 3.8) ( 3.8) ( 1.9) ( 0.0) ( 0.0) ( 7.5) ( 0.0) ( 9.4) ( 0.0) ( 0.0)
(39.1) (26.1) ( 0.0) ( 0.0) ( 7.2) ( 1.4) ( 8.7) ( 0.0) ( 0.0) ( 1.4) ( 4.3) ( 2.9) ( 1.4) ( 0.0) ( 0.0) (15.9) ( 1.4) ( 2.8) ( 0.0) ( 0.0)
n (o/o)
(37.5) (33.3) (10.4) ( 0.0) ( 4.2) ( 0.0) ( 6.3) ( 0.0) ( 0.0) ( 2.1) ( 2.1) ( 0.0) ( 2.1) ( 0.0) ( 0.0) ( 8.3) ( 0.0) ( 6.3) ( 0.0) ( 0.0)
P
n.s. n.s. CO.005 n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. ns. n.s.
30.6%, excluding tobacco dependence. With regard to the psychiatric prevalence rate in general, our findings were consistent with those obtained by the four earlier studies that examined rates for specific disorders in primary care settings using structured diagnostic interviews [1,6,9,101. However, our results cannot be precisely compared with these reports because these prior epidemiologic rates are based on period prevalence and there are differences in instruments and diagnostic criteria. Although it is important to recognize that the prevalence rates differ according to the time period employed for measurement, we made a general comparison with previous studies. Furthermore, we compared our lifetime prevalences with those of communities in the U.S. Another comparison was made with lifetime prevalence of community and inpatients in Japan. The study of Hoeper et al. 111 in Mansfield, Ohio has a similar methodology. They used the GHQ as a screening instrument, followed by a Schedule for Affective Disorder and Schizophrenia [SADS] interview to obtain the Research Diagnostic Criteria [RDCI for the diagnoses. The prevalence rate of RDC mental disorder for the adult primary care
Psychiatric Disorders in a General Medicine Clinic
Table 5. Validity of the Japanese
GHQ
version of the GHQ for different cutoff points
scores
Sensitivity t%)
Specificity (%)
Positive predictive value (%)
Negative predictive value (%)
2/3 3/4 4/5 5/6 6/7 7/8 8/9 9/10 10/11 11/12 12/13 13/14
86.5 84.6 73.6 73.6 65.4 61.5 48.1 44.2 44.2 42.3 42.3 40.4
30.5 39.8 46.2 53.0 60.2 66.9 71.2 78.0 82.2 83.1 88.1 89.8
35.4 38.3 38.2 41.5 42.0 45.1 42.4 46.9 52.3 52.4 61.1 63.6
83.7 85.5 79.4 81.6 79.8 79.8 75.7 76.0 77.0 76.6 77.6 77.4
Overall misclassification
(%)
52.4 46.5 45.3 40.6 38.2 34.7 35.9 32.4 29.4 29.4 25.9 25.3
Taking off patients in one diagnostic category of tobacco dependence.
patient population was 26.7%. The rate of major depression (DSM-III) reached 5.8%, somewhat consistent with ours. Schulberg et al. [6] used a two-stage case identification method: a self-report screening (the Center for Epidemiological Studies Depression Scale) and DIS interview on a sample of patients from three primary medical care centers. Using current DIS/DSM-III diagnoses, the prevalence rate of all disorders was 31.3%, excluding tobacco dependence and psychosexual dysfunction. Among the patients who participated in the DIS interview, the proportion of patients considered as having depressive disorders was 9.2%. Frequent diagnoses were alcohol abuse (8.2%), substance abuse (5.8%), and antisocial personality (5.8%). The lifetime prevalence of alcohol abuse and dependence in our study was 9.4%. This rate was slightly higher than that found by Schulberg et al. 161. This difference might be due to the lifetime prevalence measure in the current study. However, our prevalences of drug abuse and dependence and antisocial personality were notably lower than theirs. Nishioka et al. [14] reported a low rate of drug abuse and dependence (0%) and antisocial personality (1 .O%) among internal medicine and orthopedic patients in Japan, based on the lifetime prevalence using the DIS-JM interview. This phenomenon was also observed in the Taiwanese community population 1251. It seems
apparent
that the urban
population
in the U.S. is quite different in other ways, even though this study was not carried out in a primary care practice in a large Japanese metropolitan population. Honda 1261 pointed out that the type of
personality disorders described in DSM-III were unfamiliar to Japanese psychiatrists. Another reason is that several cultural-specific factors may contribute significantly to the low prevalence rates of drug abuse and dependence and antisocial personality in Japanese primary care. Von Korff et al. [9] examined an inner-city clinic in Baltimore using the GHQ for the initial screening and the DIS interview to establish a psychiatric diagnosis. The DIS/DSM-III diagnostic rates for specific depressive disorders were 5.0% for major depression and 3.7% for dysthymia. Though the rate for alcohol abuse and dependence was 5.0%, the overall rate for all disorders assessed by the DIS interview was 25.0%. Our report shows conformity with regard to major depression. Barrett et al. [lo] assessed patients from a rural primary care practice for all psychiatric disorders (RDC categories) and found the prevalence to be 26.5%. RDC depressive disorders represented 10.0% of the total, and the anxiety-related disorders, 5.3%. According to the above reports based on period prevalence, there was considerable consistency in the rates of all psychiatric disorders twenty-five percent to 30% of primary care patients were found to have some psychiatric disorders. This suggests that the most common psychiatric disorders observed in primary care practice are alcohol abuse and dependence, and depression. These diagnoses are in part similar to the epidemiologic reports from three U.S. urban communities (Baltimore, St. Louis, and New Haven, Connecticut) surveyed by the Epidemiologic Catchment Area (ECA) study, based on lifetime preva229
T. Sato and M. Takeichi
lence using the DIS interview 127,281. These trends were also noted at Durham, Los Angeles 129-311, and Puerto Rico 1321. Regarding depression, Robins et al. [27] reported that the lifetime prevalence of major depressive episodes ranged from 3.7% to 6.7% from the three sites of the ECA study, whereas a prevalence rate of 6.0% for the Japanese general population in Ichikawa city 1331 and a 6.5% prevalence rate was found among internal medicine and orthopedic inpatients in Japan 1141. Generally, compared with the community population, the population of adult primary care patients has a disproportionately high concentration of patients with mental disorders Ill. According to Schulberg et al. 161, Von Korff et al. 191, and Barrett et al. 1101, the period prevalence of depression among the primary care population using the structured assessment procedure was 9.2%, 8.7%, and lO.O%, respectively. A rate of 4.7% for lifetime prevalence of major depressive episode obtained in this study was lower than that of the general population (6.0%) and inpatients (6.5%) in Japan 114,331. However, with regard to somatization disorder, the lifetime prevalence of primary care patients (2.4%) showed a disproportionately high concentration compared with the general population (1.0%) in Japan 1331; this suggests that patients with somatization disorder are relatively rare in the community but are associated with higher rates of seeking health care in primary care settings, compared with major depressive episode in Japan. On the other hand, one point of interest is the lower rate of “all depressives” in comparison with previous reports on U.S. primary care patients [6,9,101. Kleinman [341 stated that from the crosscultural standpoint, “the somatic idiom for expressing depressive feeling among Chinese constitutes that affect as a vegetative experience profoundly different from its intensely personal, existential quality among middle-class Americans,” Similarly, Marsella 1351 showed that “among the Japanese the same effect is communicated in an external, naturalistic metaphor-clouds, rain, mistthat again appears to produce a distinct difference in the quality of the experience of depressive effect.” This cultural background might explain the lack of Japanese study sample responses to the symptom questions for depression in the DIS interview. However, it is likely that the major influence of illness behavior theory and classification has been in relation to disorders presenting with functional symptoms as, for instance, somatoform disorder and the Axis V category, “Noncompliance 230
with Medical Treatment” J361. In recent studies of Katon et al. 137-391 and Von Korff et al. 1401, somatic idioms of distress in the U.S. have been discussed, and several mechanisms that explain the association between mental illness and medically unexplained somatic symptoms have been reported by analyzing the characteristics of distressed high utilizers of medical care. Somatization has been described as the presentation of psychosocial distress in an idiom of physical symptom J41-431. Our clinical data cannot shed light on the mechanisms linking psychological disorders and somatic complaints. With regard to the problem of misdiagnosis of depression in general medical settings, Katon [441 has questioned whether the clinical syndromes are the same or different in psychiatric patients who are depressed. Williamson and William 1451 have pointed out that patients presenting with depression in a general medical setting tend to be in an earlier, milder, and “unorganized” stage of the illness compared with those in a psychiatric speciality setting. Medical patients are less psychologically experienced and less sophisticated in their ability to describe their symptoms. These findings as well as cultural influences upon the way depression is experienced in Japan may further explain the relationship between somatic complaints and depression. Understanding the changes in somatic complaints during the course of depression may help researchers further define the relationship between depression and somatization 1461. In addition to the prevalence rate, we determined the relationship of the demographic variables to the specific disorders in the primary care setting. According to Robins et al. [27], in a community sample based on the lifetime prevalence of DIS interview, the clearly predominant disorders in males were antisocial personality and alcohol abuse and dependence. But among females, depressive episodes and phobia prevailed. In this study, our observations correspond to Robins’s, with the exception of the antisocial personality and phobic disorders. The striking finding of this study is that the organic brain syndrome (e.g., dementia) appears most frequently in the female group aged 55-80 years. We think the increase in this organic brain syndrome prevalence is the reflection of the aging of the Japanese population, especially Japanese females, who have a life-span of 82.1 years, the longest in the world 1471. In general, primary care providers are likely to play an important role in any improvement of the
Psychiatric Disorders in a General Medicine Clinic
detection and treatment
of mental disorders. There is now growing evidence that more than half of all patients receiving treatment for mental disorders receive care from primary care physicians only. Of those people with depressive symptoms who seek medical care, 80% are evaluated by primary care physicians, and only 20% consult mental health specialists, of which 50% are psychiatrists 148501. Thus, we should provide educational training for depression, alcohol abuse and dependence, and organic brain syndrome to primary care physicians to improve the sensitivity of screening in the Japanese primary care population.
Validity of the Japanese Version of the GHQ among Primary Care Patients Prior to the present investigation, two studies examined the validity of the GHQ in Japan. In the first study, Nakagawa and Daibo [ill distributed the 60-item GHQ to two groups of subjects: normal volunteers whose mental state had been confirmed to be nonpsychiatric by the Present State Examination interview, and psychiatric patients known by the investigators. This study found the cutoff point of 14/15 for the 60-item GHQ to be the most discriminating for the Japanese population. In the second study, Kitamura et al. 1121 examined the validity of the GHQ using the semistructured interview based on RDC as external criteria among antenatal clinic patients. The recommended cutoff point was 7/8, taking into account the resulting balance of sensitivity (88.9%) and specificity (71.1%). The result of the current study using the DIS interview as external criteria suggests an optimum threshoid score of 7/8. This cutting score is associated with a specificity of 66.9% and an overall misclassification rate of 34.7%. It is regrettable, however, that specificity and sensitivity were not above 70%. It is difficult to extrapolate these results to the other studies because the sensitivity and specificity depend on the proportion of the screened populations with positive results for a given screening method. Cleary et al. [511 showed that the resultant sensitivity of the 30-item GHQ is 7S%, and the specificity is 85% in the Wisconsin study using the SADS-lifetime interview as external criteria. Another explanation for the low sensitivity and specificity in this sample is that “caseness” was defined using the lifetime DIS diagnoses. The GHQ screens for current symptoms and, except in the
case of presumably chronic or unremitting disorders, it is not surprising that GHQ current results may not be sensitive or specific to lifetime DSM-III disorders. Thus, the GHQ should be better at predicting the current “caseness” on structured psychiatric interviews. In conclusion, the results of this study present more problems than solutions concerning the psychiatric care of primary care patients. Further Japanese epidemiologic studies in primary care are needed to examine the prevalence of psychiatric illness and screening scales to better detect this illness. Of special interest, because of this high prevalence, will be the recognition and treatment of aIcoho1 abuse and dependence, major depressive episode, and organic brain syndrome by the primary care physicians in Japan. We would like to thnnk Prof. M. Nishizono of fhe Psychiatry Department, School of Medicine in Fukuoka University for giving us the opportunity of training in the DIS interview. We also thank Prof. M. Nishizumi of the Community Health Science Department of Saga Medical School for advice in the epidemiology, as well as Dr. H. Nakao, former president of Saga Medical School Hospital, and Prof. T. Fukui of the Department of General Medicine Clinic, Saga Medical Srkoot, for their cunfinuous guidance and encouragement in this study.
References 1. Hoeper EW, Nycz GR, Cleary PD, Regier DA, Gold-
berg ID: Estimated prevalence of RDC mental disorder in primary medical care. Int J Ment Health 8: 6--15,1979 2. Cooper B: Psychiatric illness in general medical prac-
3.
4. 5.
6.
7.
8.
9.
tice. An investigation in Mannheim. Int J Rehabil Res 4:86-88, 1981 Hough R, Landsverk J, Stone J, et al: Comparison of psychiatric screening questionnaires for primary care patients. Report on contract 278-81-0036 (DB). Rockville, MD, National Institute of Mental Health, 1983 Hoeper E, Nycz G, Kessler L, et al: The usefullness of screening for mental illness. Lancet i:33-35, 1984 Skuse D, Williams P: Screening for psychiatric disorder in general practice. Psycho1 Med 14:365-377, 1984 Schulberg HC, Saul M, McClelland M, et al: Assessing depression in primary medical and psychiatric practices. Arch Gen Psychiatry 42:1164-1170, 1985 Bellantuono C, Fiorio R, Williams P, et al: Psychiatric morbidity in an Italian general practice. Psycho1 Med 17243-247, 1987 Kessler L, Burns B, Shapiro S, Tischler G, et al: I’sychiatric diagnoses of medical service users: evidence from the Epidemiologic Catchment Area Program. Am J Pub Health 77:18-24, 1987 Von Korff M, Shapiro S, Burke JD, et al: Anxiety and
231
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depression in a primary care clinic. Arch Gen I’sychiatry 44:152-156, 1987 10. Barrett JE, Barrett JA, Oxman TE, Gerber I’D: The prevalence of psychiatric disorders in a primary care practice. Arch Gen Psychiatry 45:1100-1106, 1988 11. Nakagawa Y, Daibo I: Validity and reliability of the Japanese version of the General Health Questionnaire and its clinical application. National Institute of Mental Health, Japan, 1981 (in Japanese) 12. Kitamura T, Sugawara M, Aoki M, Shima S: Validity of the Japanese version of the GHQ among antenatal clinic attendants. Psycho1 Med 19:507-511, 1989 13. Nonaka Y, Nishizono M, Yamamoto J: Neurosis from the viewpoint of DIS (Diagnostic Interview Schedule). Jpn J Psychiatr Neurol 43:591-618, 1989 14. Nishioka Y, Nishizono M, Yamamot J: The distribution of mental illness found by DIS (Diagnostic Interview Schedule) among internal and orthopedic patients. Jpn J Psychiatr Neurol 44:33-54, 1990 15. Nishizono M, Nagamoto A, Yamamoto J, Nanaka Y: Concordance rate between clinical and DIS diagnoses: a cross-cultural comparison. Jpn J Psychiatr Neurol45:577-581, 1991 16. Cochran WG: Sampling Techniques, 3rd ed. New York, John Wiley & Sons, 1977 17. Goldberg D, Rickels K, Downing R, et al: A comparison of two psychiatric screening tests. Br J Psychiatry 129:61-67, 1976 18. Robins LN, Helzer JE, Croughan J, Ratcliff KS: National Institute of Mental Health Diagnostic Interview: its history, characteristic, and validity. Arch Gen Psychiatry 38:381-389, 1981 19. Robins LN, Helzer JE, Ratcliff KS, Seyfried W: Validity of the Diagnostic Interview Schedule, Version II: DSM-III diagnoses. Psycho1 Med 12:855-870, 1982 20. Helzer JE, Robins LN, McEvory LT, et al: A comparison of clinical and diagnostic interview schedule diagnoses. Arch Gen Psychiatry 42:657-666,1985 21. SAS Institute Inc: SAS companion for the UNIX environment and derivatives. North Carolina, SAS Institute Inc., 1990 22. SAS Institute Inc: SAS/STAT User’s Guide. North Carolina, SAS Institute Inc., 1990 23. Goldberg D: The Detection of Psychiatric Illness by Questionnaire: A Technique for the Identification and Assessment of Non-psychotic Illness (Maudsley monographs, No.21). London, Oxford University Press, 1972 24. Schulberg HC, Burns BJ: Mental disorders in primary care: epidemiologic, diagnostic, and treatment research directions. Gen Hosp Psychiatry 10:79-87, 1988 25. Hwu HG, Yeh EK, Chang LY: Prevalence of psychiatric disorders in Taiwan defined by the Chinese Diagnostic Interview Schedule. Acta Psychiatr Stand 79:136-147, 1989 26. Honda Y: DSM-III Japan. In Spitzer RL, Williams JBW, Skodol AE feds), International Perspectives on DSM-III. Washington, American Psychiatric Press, Inc., 1983, pp. 185-201 27. Robins LN, Helzer JE, Weissman MM, et al: Lifetime prevalence of specific psychiatric disorders in three sites. Arch Gen Psychiatry 41:949-958, 1984
232
28. Myers JK, Weissman MM, Tischler GL, et al: Sixmonth prevalence of psychiatric disorders in three communities 1980 to 1982. Arch Gen Psychiatry 41: 959-967, 1984 29. Burnam MA, Hough RL, Escobar JI, et al: Six-month prevalence of specific psychiatric disorders among Mexican Americans and non-Hispanic whites in Los Angeles. Arch Gen Psychiatry 44:687-694, 1987 30. Karno M, Hough RL, Burnam MA, et al: Lifetime prevalence of specific psychiatric disorders among Mexican Americans and non-Hispanic whites in Los Angeles. Arch Gen Psychiatry 44:695-701, 1987 31. Regier DA, Boyd JH, Burke JD, et al: One-month prevalence of mental disorders in the United States: based on five epidemiologic catchment area sites. Arch Gen Psychiatry 45:977-986, 1988 32. Canino GJ, Bird HR, Shrout PE, et al: The prevalence of specific psychiatric disorder in Puerto Rico. Arch Gen Psychiatry 44~727-735, 1987 33. Machizawa S: A comparison of the alcohol abuse and dependence prevalence in Asian countries and the US. The 4th Scientific Meeting of the Pacific Rim College of Psychiatrist, Hong Kong, 1988 34. Kleinman A: Patients and Healers in the Context of Culture. Berkeley, University of California Press, 1980 35. Marsella AJ: Depressive experience and disorder across cultures. In Triandis H, Draguns J (eds), Handbook of Cross-Cultural Psychology, Vo15: Culture and Psychopathology. Boston, Allyn and Bacon, 1977, pp. 30-72 36. Mayou R: Illness behavior and psychiatry. Gen Hosp Psychiatry 11:307-312, 1989 37. Katon W, Von Korff M, Lin E, et al: Distressed high utilizers of medical care- DSM-III-R diagnoses and treatment needs. Gen Hosp Psychiatry 12:355-362, 1990 38. Katon W, Lin E, Von Korff M, Russo J, Lipscomb P, Bush T: Somatization: a spectrum of severity. Am J Psychiatry 148:3&O, 1991 39. Katon W, Von Korff M, Lin E, et al: A randomized trial of psychiatric consultation with distressed high utilizers. Gen Hosp Psychiatry 14:86-98, 1992 40. Von Korff M, Ormel J, Katon W, Lin EHB: Disability and depression among high utilizers of health care. Arch Gen Psychiatry 49:91-100, 1992 41. Katon W, Kleinman A, Rosen G: Depression and somatization. A review. Am J Med 72:127-135,241-247, 1982 42. Katon W: Panic disorder: epidemiology, diagnosis and treatment in primary care. J Clin Psychiatry 47(Suppl):21-27, 1986 43. Barsky AJ, Klerman GL: Overview: hypochondriasis, bodily complaints, and somatic styles. Am J Psychiatry 140:273-283, 1983 44. Katon W: Deuression: somatic svmutoms and medical disorders’in primary care. Cbm’pr Psychiatry 23: 274-287.1982 45. Williamson I’, William RY: The initial presentation of depression in family practice and psychiatric outpatients. Gen Hosp Psychiatry 11:188-193, 1989 46. Sato T, Sakihata H, Takeichi M: Studies on general medicine clinic psychiatry: a comparison of 30-item
Psychiatric Disorders in a General Medicine Clinic
General Health Questionnaire results between general medicine clinic and psychiatric clinic depressive patients treated with sulpiride. Kyushu N-psych 37: 240-246, 1991 (in Japanese) 47. Health and Welfare Statistics Association: life table. J Health Welfare Statistics (Suppl) 39:72-79, 1992 (in Japanese) 48. Weissman MM, Myers JK: Rates and risks of depressive symptoms in a United States urban community. Acta Psychiatr Stand 57219-231, 1978
49. Regier DA, Goldber ID, Taube CA: The de facto US mental health services system. Arch Gen Psychiatry 35:685-693, 1978 50. Schurman RA, Kramer I’D, Mitchell JB: The hidden mental health network: treatment of mental illness by nonpsychiatrist physicians. Arch Gen Psychiatry 42: 89-94, 1985 51. Cleary I’D, Goldberg ID, Kessler LG, Nycz GR: Screening for mental disorder among primary care patients. Arch Gen Psychiatry 39:837-840, 1982
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