Gender Differences in Prevalence of Somatoform Disorders in Patients Visiting Primary Care Centers

Abstract

The aim of this study was to examine the gender differences in the prevalence of somatoform disorders among a sample of Qatari patients who were visiting primary health care centers and to investigate the severity of diagnostic categories and the most frequent somatic symptoms in these patients. The first stage of the study was conducted with the help of general practitioners, using the somatic symptom module of the Patient Health Questionnaire 12-item General Health Questionnaire. Overall, 2320 subjects were approached, and a total of 1689 patients, of whom 892 were men and 797 were women, agreed to participate in the study. The prevalence rate of somatoform disorders among the total screened sample was 23.9%. The prevalence rate was slightly higher in Qatari women (24.2%) than in Qatari men (23.7%). Housewives (43.5%) and men in administrative posts (37.9%) reported higher somatic symptoms compared to other professions. Prolonged depressive reaction was significantly higher in women compared to men (P = .003). There was a significant gender difference in certain psychiatric diagnostic categories such as depressive episode, recurrent depressive disorder, dysthymia, and brief depressive reaction. Backache was the most common reported symptom in men, whereas headache was more common in women. The present study revealed that the prevalence of somatoform disorders in Qatar is as high as the overall prevalence reported in prior studies done in other primary care settings. The prevalence of somatoform disorders was slightly higher in Qatari women than in men.

Keywords

somatic symptoms primary health care determinants Qatar

Introduction

Mental disorders such as somatization, anxiety, depression, and alcohol abuse are prevalent in general practice but often underrecognized.¹ Most researchers show that 1 in 4 people will experience a mental health problem at some point in their lives. Although the overall prevalence of mental illness is common in both women and men, there are clear gender differences in the occurrence.² Verdonk et al explained that this difference between genders is owing to the multiple interactions between biological, psychological, social, cultural, and societal factors.³ Women have greater rates of depression, anxiety disorders, and somatization compared to men. Conversely, men have greater rates of substance abuse disorders and some personality disorders.⁴ Overall, there is a clear consensus on gender differences in mental illness.

In Western countries, studies in which standardized methods have been used show that 14% to 36% of patients in primary care settings have mental disorders.⁵ Medically unexplained somatic complaints are among the most common clinical presentation in primary care in developing countries, and if left untreated, they impose considerable burden of disease for the health care system. Many patients present with unexplained physical symptoms rather than psychological complaints, resulting in an excess number of costly clinical investigations. Mental disorders are diagnosed in 33% to 60% of the cases by the general practitioners,⁶ but the somatization disorders recognized by general practitioners have only been sparsely studied.

Somatization is not a disease entity but a process whose result is the illness experience of medically unexplained symptoms. Somatization is a universal phenomenon; indeed, some authors have argued that it is psychologization—the presentation of common mental disorder as psychological symptoms—that is the more unusual presentation.⁷

Research studies published over the past 2 decades indicate that patients presenting with symptoms lacking adequate medical basis are commonly encountered in all medical care settings.^8-14 Most somatisizing patients present with multiple symptoms, referring to any body part, function, or organ system and imitating any bodily disease, especially pain. Somatization does not imply that the patient does not have a concurrent physical illness as they can coexist and be facilitated by each other. Somatization is hypothesized to be an expression of personal and social distress in the form of bodily complaints with medical help seeking. It is also reported that the high stigma attached to mental disorders in some cultures may have a compounding effect.¹⁵

Although the gender difference in prevalence rates of depression is well established, few studies have examined gender differences in the clinical features of depression. It is believed that women visit general practitioners and outpatient clinics more frequently because they are more apt to acknowledging psychological distress and seeking help for it. Gender differences can furthermore be explained either psychosocially or biologically, although it is likely that both groups of factors interact in complex ways.¹⁶

There has been limited research on the clinical presentation of somatic symptoms and the prevalence and etiology of somatic complaints in primary care settings in developing countries.¹⁷ Also, in the Middle East region, to our knowledge, very little information is available regarding gender differences in the prevalence of somatization in the general population. This research is the first report showing the prevalence of gender difference in somatoform disorders in primary care patients in Qatar.

Method

This is a cross-sectional study based on the primary health care clinics of Qatar. The survey was conducted among Qatari nationals between 25 and 65 years of age during the period from January to July 2007.

A multistage, stratified random sampling design was developed using an administrative division of the Qatar into 21 primary health care centers in terms of number of inhabitants. Of these health centers, 7 health centers in urban areas and 3 health centers in semi-urban areas were visited mostly by Qatari people; the remaining health centers were excluded from the survey. Also, the selected 10 health centers represent geographically the central location of the Qatari population. We have taken an equal proportion of Qatari subjects from these selected health centers according to the Qatari inhabitants in that district. The sample size was determined on the a priori presumption that the prevalence rate of somatization in Qatar would be more or less similar to rates found for several other countries in the Arabian Gulf and Eastern Mediterranean,^18,19 where the reported prevalence of somatization among adults ranged from 15% to 20%. Assuming the prevalence of somatization to be 17%, with the 99% confidence interval for an error of 2% at the level of significance, a sample size of 2320 would be required to meet the specific objectives of the study. Of the total 22 primary health care clinics available, 10 were selected at random. Of these, 8 were located in urban and 2 in semi-urban areas of Qatar. During the study period, 2320 subjects were approached, of whom 1689 responded to the questionnaire, with a response rate of 72.8%. A total of 1689 patients with 892 men and 797 women were screened for the presence of somatization. The screening procedure identified and confirmed a total of 404 cases eligible for clinical interviewing using the Clinical Interview Schedule (CIS) and International Classification of Diseases–10 (ICD-10) diagnostic criteria.

To avoid ambiguity and overgeneralization in using the term somatization in this sample, we adopted the restrictive operational criteria set by Bridges and Goldberg²⁰ and Bener et al.²¹

Psychiatric Instruments

Arabic version of the 12-item General Health Questionnaire (GHQ-12).^22,23

The GHQ was developed by Goldberg as a self-administered questionnaire that would identify nonpsychotic psychiatric cases. Somatization was measured using the somatic symptom module of the Patient Health Questionnaire GHQ-12.¹⁰ The Arabic version of the GHQ-12 has already proven to be a valid instrument for screening for psychiatry morbidity among Arab primary health care patients in Qatar.²³

The CIS.²⁴

The CIS is a semi-structured psychiatric questionnaire developed for use in community surveys. It consists of questions designed to elicit the presence or absence of 10 defined psychiatric symptoms and 12 manifest abnormalities. Each item of psychiatric symptoms and manifest abnormality was graded based on 4 points (0-4), with 0, absent; 1, mild; 2, moderate; 3, severe; and 4, very severe. The total weighted score is calculated by adding the sum of the 10 “reported symptoms” scores plus twice the sum of the 12 “manifest abnormality” scores. For the purpose of this study, the criteria used to define a psychiatric case was a total weighted score of 20 or more. This threshold was found appropriate when previously used in United Arab Emirates^18,21 and in Qatar.²³

Procedure

A psychiatrist and 2 general practitioners carried out the research assessments, both of whom had previous training. Training involved 2 sessions for administering the GHQ-12, the sociodemographic questionnaire, CIS, and the procedure as a whole.¹⁰

After dealing with the presenting complaint, eligible patients were invited by the general practitioner to take part in our study. The purpose of the study was explained for obtaining consent, and confidentiality was emphasized to all participants. Identified cases were assigned diagnoses according to the ICD-10²⁶ classification of mental illness. The severity of their illness was measured according to the total weighted score.

The Student t test was used to ascertain the significance of differences between mean values of 2 continuous variables. Chi-square analysis was performed to test for differences in proportions of categorical variables between 2 or more groups. In 2 × 2 tables, the Fisher exact test (2-tailed) replaced the χ² test if the assumptions underlying violated, namely in case of small sample size and where the expected frequency is less than 5 in any of the cells. The level P < .05 was considered as the cutoff value for significance.

Results

From the total screened 1689 Qatari patients with 892 men and 797 women, 404 cases (23.9%) were identified for CIS, with 211 men and 193 women. Mean age ± SD of men and women with somatoform disorders was 37.9 ± 7.7 and 38.3 ± 6.2, respectively.

Table 1 shows the sociodemographic characteristics of the studied patients with somatoform disorders by gender. The prevalence of somatoform disorders among the surveyed patients was slightly higher in women (24.2%) than in men (23.7%). Of the identified cases, somatic symptoms were higher in men (52.2%) than in women (47.8%). There was a significant difference between men and women in their age group (P = .031) and level of education (P = .008). Housewives (43.5%) and men in administrative posts (37.9%) reported higher somatoform disorders compared to other professions. Symptoms occurred more often in men in the age group 30 to 39 years and women in the age group 40 to 49 years. Symptoms were less prevalent in patients older than 50 years (8.1% men and 5.2% women). Marital status was not a significant factor in either gender.

Table 1.

The Sociodemographic Characteristics of the Studied Patients With Somatoform Disorders by Gender

	Men (n = 211)		Women (n = 193)
Variable	n	%	n	%	P
Age, y
<30	36	17.1	19	9.8	.031
30-39	91	43.1	80	41.5
40-49	67	31.8	84	43.5
50-60	17	8.1	10	5.2
Marital status
Currently single	32	15.2	36	18.7	Not significant
Currently married	179	84.8	157	81.3	Not significant
Educational level
Illiterate	33	15.6	23	11.9	.008
Elementary	33	15.6	43	22.3
Intermediate	76	36.0	42	21.8
Secondary	37	17.5	46	23.8
University	32	15.2	39	20.2
Occupation
Businessman	47	22.3	6	3.1
Clerical/administrative	80	37.9	53	27.5
Police/military	54	25.6	8	4.1
Housewife	0	0.0	84	43.5
Professional	30	14.2	42	21.8
Smoking habits
Never smoked	130	61.6	171	88.6	<.001
Ex-smoker	48	22.7	4	2.1
Current smoker	33	15.6	18	9.3

Table 2 summarizes the ICD-I0 diagnostic categories and their severity in patients with somatoform disorders by gender. The severity of prolonged depressive reaction was significantly higher in women (32.2 ± 7.3) than in men (26.3 ± 6.2; P = .003). There was a significant difference found between men and women in certain diagnosis categories: depressive episode, recurrent depressive disorder, dysthymia, and brief depressive reaction. But for the severity of illness, no statistically significant differences were found as to gender except in prolonged depressive reaction (P = .003).

Table 2

The ICD-10 Diagnostic Categories and Their Severity in Men and Women^a

	Men (n = 211)		Women (n = 193)			TWS
Diagnosis	n	%	n	%	P	Men	Women	P
Generalized anxiety disorder	34	16.1	35	18.1	.590	23.9 ± 5.5	27.3 ± 9.4	.072
Mixed anxiety and depressive disorder	67	31.8	48	24.9	.126	30.9 ± 9.0	32.2 ± 9.0	.446
Depressive episode	10	4.7	33	17.1	<.001	24.2 ± 6.8	26.4 ± 6.7	.369
Recurrent depressive disorder	39	18.5	18	9.3	.008	31.8 ± 6.6	30.4 ± 7.1	.470
Dysthymia	20	9.5	5	2.6	.004	26.5 ± 6.1	27.2 ± 4.4	.812
Brief depressive reaction	7	3.3	15	7.8	.049	28.7 ± 8.3	24.6 ± 7.2	.247
Prolonged depressive reaction	28	13.3	33	17.1	.283	26.3 ± 6.2	32.2 ± 7.3	.003
Somatization disorder	5	2.4	2	1	.405	27.2 ± 3.8	22.0 ± 0.0
Obsessive compulsive disorder	0	0	3	1.6			36.0 ± 0.0
Social phobia	1	0.5	1	0.5		29.0	29.0

ICD-10, International Classification of Diseases (10th revision); TWS, total weighted score (data are mean ± SD).

Table 3 shows the comparison of postulated determinants in the studied patients with somatoform disorders by gender. Physical illnesses during childhood (P = .022) and adulthood (P = .029) were significantly higher in men, whereas family history of psychiatric disorder (P = .012) and dissatisfaction in social life (P < .001) were higher in women.

Table 3.

Comparison of Postulated Determinants in the Studied Patients With Somatoform Disorders by Gender^a

	Men (n = 210)		Women (n = 194)
Variable	n	%	n	%	P
Significant physical illness during childhood	43	20.4	23	11.9	.022
Other adverse childhood experiences	92	43.6	85	44.0	NS
Significant physical illness during adulthood before the onset of presenting symptoms	46	21.8	26	13.5	.029
Family history of significant physical illness	64	30.3	52	26.9	NS
Dissatisfaction, during the 12 months before the onset of symptoms, with:
Marital and/or family life	105	49.8	97	50.3	NS
Work	88	41.7	84	43.5	NS
Social life	135	64.0	154	79.8	<.001
Family history of psychiatric disorder	27	12.8	43	22.3	.012
Stressful life events within the 12 months before the onset of the presenting symptoms (other than the above)	115	54.5	104	53.9	NS

NS, not significant.

Table 4 shows the most frequent somatic symptoms of the studied patients by gender. Backache was the most common reported symptom in men (45.5%), whereas headache was more prevalent in women (55.4%). The second most common symptom in men was headache (37.0%) and fatigability in women (46.1%). A significant difference was found between men and women in terms of headache (P < .001), abdominal pain (P = .035), pain in the extremities (P = .027), fatigability (P = .031), joint pain (P = .026), dizziness (P = .001), diarrhea (P = .041), and chest pain (P = .004).

Table 4.

The Most Frequent Somatic Symptoms of the Studied Patients by Gender^a

	Men (n = 211)		Women (n = 193)
Somatic Symptom	n	%	n	%	P
Headache	78	37.0	107	55.4	<.001
Backache	96	45.5	74	38.3	NS
Fatigability	75	35.5	89	46.1	.031
Pain in the extremities (upper and lower limbs)	54	25.6	32	16.6	.027
Generalized aches and pains	54	25.6	37	19.2	NS
Abdominal pain	49	23.2	63	32.6	.035
Dizziness	38	18.0	62	32.1	.001
Diarrhea	37	17.5	50	25.9	.041
Joint pain	14	6.6	4	2.1	.026
Pain/discomfort in the throat	11	5.2	10	5.2	NS
Breathlessness	10	4.7	10	5.2	NS
Chest pain	8	3.8	22	11.4	.004
Cough	4	1.9	3	1.6	NS
Sexual dysfunction	4	1.9	0	0.0
Weakness (or paralysis) of part/parts of the body	4	1.9	0	0.0
Palpitations	0	0.0	5	2.6
Irregular menstrual bleeding	0	0.0	5	2.6
Pain in the breast	0	0.0	3	1.6
Skin itching	0	0.0	2	1.0

NS, not significant.

Discussion

It is known that patients with somatic symptoms have a greater risk of developing depression. Similarly, patients with depression are more likely than are their nondepressed counterparts to develop somatic symptoms. Mental disorders are diagnosed in 33% to 60% of the cases by the general practitioners, but somatization recognized by general practitioners has only been sparsely studied.⁶ Prior studies have found similarly high prevalence rates ranging from 22% to 58% of consecutive patients presenting to primary care fulfilling the diagnostic criteria for a somatoform disorder.¹ A similar proportion was found in the surveyed primary care patients in Qatar, where 23.9% were identified with somatic symptoms. A study conducted in Denmark¹ disclosed that in half of the patients with somatoform disorder, the general practitioners rated that somatization was the reason for the consultation, and in 66.7% of the cases, there were psychosocial factors affecting the patient’s condition.

During the past decade, the psychiatric literature has reflected a new level of interest in gender as a key variable in psychopathology research and psychiatric services delivery. There are important differences in types of disorders found in each gender. Boys are more likely to display the so-called externalizing disorders such as conduct disorder, whereas girls typically show the internalizing disorders of depression and anxiety.^27,28 Official figures suggest that 20% of women as opposed to 14% of men in England have some form of mental illness.²⁹ Few studies have found that somatoform disorders are more prevalent among females, and furthermore, females in general report more symptoms than do males.²⁹ The present study revealed that the prevalence of somatoform disorder was nearly equal in both genders but slightly higher in women (24.2%) than in men (23.7%). On the other hand, in a study done by Flink et al,¹ the tendency was that the prevalence was equal or higher among male patients. This study is the first attempt to document the gender differences in somatoform disorders in primary care Qatari patients.

Most studies suggest that depression and anxiety are at least 1.5 to 2 times more common in women,³ but our results show that among the identified cases, the symptoms occurred more often in men (52.2%) than in women (47.8%). This is a surprising finding but possibly could be a reflection of most Qatari women being housewives, with possibly less stress compared to that of men.

Hiller et al⁹ reported in their study that somatization is linked to a number of sociodemographic risk factors. Symptoms occurred more often in women, in the elderly, and in those with lower educational levels. This is inconsistent with our data in that there was a significant difference found between men and women in educational level. Also, it was interesting to note that the symptoms of somatization were less prevalent in educated patients with university degrees and in those who were older than 50 years.

Flink et al¹ reported that no statistically significant difference as to gender was found in any diagnostic category except for autonomic dysfunction. In contradiction to this, the present study’s findings showed significant difference between men and women in depressive episode, recurrent depressive disorder, brief depressive reaction, and dysthymia. Also, dissatisfaction with social life was significantly higher in women compared to men. A number of gender differences in social relationships have been reported in a study by Elsenberg.¹⁶

Some of the most common somatic symptoms reported by the study patients were headache, backache, abdominal pain, pain in upper and lower limbs, fatigability, pain, dizziness, and diarrhea. Kroenke and Mangelsdorff³⁰ showed that chest pain, fatigue, dizziness, headache, and dyspnoea were the most frequent symptoms found in their study. Both studies report very similar somatic symptoms in the studied patients. In another study, it was documented that pain disorders are more or equally prevalent in males, compared with females.²⁷ The present results showed that pain in the upper and lower limbs and joint pain were significantly higher in men, whereas abdominal pain and chest pain were more significant in women.

The present study has a few limitations that merit discussion. The response rate of the studied subjects is 72.8%, and nonresponse may have affected our prevalence estimates. Also, in a primary care setting, the presence of somatic disorders cannot be ruled out entirely. Because our data were based on self-report, there was no objective way to know if the responses of the participants were exaggerated. This may affect the reliability of our results.

In conclusion, the study findings revealed that the prevalence of somatoform disorders in Qatar is as high as the overall prevalence reported in prior studies done in other primary care settings. The prevalence of somatoform disorders was slightly higher in Qatari women than in men. There was a significant difference found between men and women in certain diagnosis categories and somatic symptoms. Backache was the most common reported symptom in men, whereas headache was the most frequent symptom in women.

Footnotes

Acknowledgements

This work was generously supported and funded by the Hamad Medical Corporation, Grant No. 377-06 HMC, Doha, the State of Qatar.

The author(s) declared no potential conflicts of interests with respect to the authorship and/or publication of this article.

The author(s) received financial support from the Hamad Medical Corporation, Grant No. 377-06 HMC for the research and authorship of this article.

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Gender Differences in Prevalence of Somatoform Disorders in Patients Visiting Primary Care Centers

Abstract

Keywords

Introduction

Method

Psychiatric Instruments

Arabic version of the 12-item General Health Questionnaire (GHQ-12).22,23

The CIS. 24

Procedure

Results

Discussion

Footnotes

Acknowledgements

References

Arabic version of the 12-item General Health Questionnaire (GHQ-12).^22,23

The CIS.²⁴