Prevalence of epilepsy and comorbidity of psychiatric disorders in Iran

Seizure (2006) 15, 476—482

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Prevalence of epilepsy and comorbidity of psychiatric disorders in Iran Mohammad Reza Mohammadi a,b,*, Ahmad Ghanizadeh a,c, Haratoun Davidian a, Mohammad Mohammadi b,d, Maryam Norouzian a a

Psychiatry and Psychology Research Center, Tehran University of Medical Sciences, Roozbeh Hospital, South Kargar St., 13185/1741 Tehran, Iran b National Research Center for Medical Sciences of Iran, Tehran, Iran c Department of Psychiatry, Shiraz University of Medical Sciences, Hafez Hospital, Shiraz, Iran d School of Medicine, Azad University of Medical Sciences, Tehran, Iran Received 29 July 2004; received in revised form 19 May 2006; accepted 23 May 2006

KEYWORDS Epilepsy; Psychiatric disorders; Community; Prevalence; Comorbidity; Iran

Summary Problem: To determine the lifetime prevalence of self- and other relative informants-reported epilepsy in nationwide study among Iranian adults of aged 18 years and over and to study the association of epilepsy with lifetime history of the psychiatric disorders. Method: Twenty-five thousand one hundred and eighty individual were selected through a randomized clustered sampling method from all the Iranian households; interviewed and used epilepsy questionnaire face-to-face at home in year 2001. From 12,398,235 households residing in Iran, 7795 families selected from 1559 clusters, 997 clusters were in urban and 582 were in rural areas, each cluster with 5 households were studied. The response rate was 90%. Results: The prevalence of epilepsy was 1.8%. Epilepsy was more common in females, unemployed and higher educational level. It was not significantly associated with the age group, marital status and residential areas. The most common psychiatric disorders in subjects with epilepsy were major depressive disorder and obsessive compulsive disorder. The rate of lifetime suicidal attempt was 8.1%. Conclusion: Lifetime prevalence of epilepsy in Iran is not low. As the other communities, it is more common in females and unemployed. However, in contrast with the other studies, it was not more common among some age groups and unmarried and low educated subjects. # 2006 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

* Correspondence to: Roozbeh Hospital, Psychiatry Research Center, Kargar Ave., Tehran 13334, Iran. Tel.: +98 21 912 123 6615; fax: +98 21 541 9113. E-mail addresses: [email protected], [email protected] (M.R. Mohammadi). 1059-1311/$ — see front matter # 2006 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.seizure.2006.05.011

Prevalence of epilepsy and psychiatric disorders in Iran

Introduction One of the powerful tools in medical science to estimate the magnitude of epilepsy in the community is epidemiology and also it helps to find out the association of some sociodemographic factors with it. Epidemiology is also a key to prevention planning programs. Hospital-based studies are always biased. Epilepsy is one of the most common neurological disorders1 and is a worldwide common chronic neurological disorder.2,3 Symptoms of epilepsy depend on the type of it and the localization of the epileptogenic focus in the brain. An epileptic event can includes motor, psychiatric, sensory auras and loss of consciousness. Approximately 3% of the general population in the United States may have epilepsy at some point in their lives.4 A community-based survey using a standardized protocol in a rural district in Tanzania revealed a prevalence of 10.2 in 1000.5 A metaanalysis reported the overall prevalence rate of epilepsy in India at 5.59 per 1000 populations, with no statistically different rates between men and women or urban and rural residence.6 Two recent studies have shown lower prevalence rates in the South Asian population.4,7 A door-to-door prevalence survey of epilepsy was conducted in Italy showed the prevalence of active epilepsy (per 1000 population) was 3.3 overall, 3.5 for men and 3.2 for women. The age-specific patterns for active epilepsy differed by sex, with higher figures for men at younger ages (5—19 years) and older ages (50—99 years).8 Factors such as sex and socioeconomic status appear to be related to the prevalence of epilepsy, with higher prevalence found in males and people in the lower socioeconomic groups.9 A study of prevalence of epilepsy in a population over 15 years of age, residing in Eastern Finland, showed that it was higher in males than in females. Age-specific prevalence of active epilepsy increased until 40—50 years of age, and declined in the oldest age groups.10 A clinical setting study in London and south east England showed that there was no apparent difference in incidence between males and females. It showed the incidence of epilepsy seems to increase with socioeconomic deprivation.11 Epilepsy is associated with poor academic achievement, unemployment and low income.12— 15 The Finnish survey found patients with uncomplicated epilepsy had at least a primary education, but that continuing education was difficult even for those with idiopathic epilepsy who were in remission without medication.16 Reduced marriage rates in patients with epilepsy have been previously reported.16,17 There are some

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reports that have highlighted the employment difficulties encountered by patients with epilepsy.16,17 Epilepsy is usually found to be slightly more common in the lower socioeconomic groups.18 It is difficult to study epilepsy in isolation from psychiatric disorders. The behavioral disturbances associated with epilepsy may be related to different factors such as the seizure discharge itself, the interictal phase or the adverse psychosocial consequences of epilepsy, central nervous system pathology, antiepileptic drugs or some could even coexist without being causally related to epilepsy. The majority of studies support the impression of an increased psychiatric morbidity in association with epilepsy. A study on epileptic patients in a psychiatry outpatient department in India showed that more than one-half of the subjects had psychiatric comorbidity.19 Suicide rate is in 0.2—0.5% of epileptic patients and causing deaths in 3—7% of them and 2—9% of patients with epilepsy have psychotic disorders.20 There is no study dealing with the epidemiology of epilepsy in Iran. We estimated the prevalence of epilepsy in Iran nationwide community-based population and its association with sex, age groups, marital status, occupation, educational level and residential area. Also, it studies the rate of positive history of the lifetime psychiatric disorders in the epileptic subjects.

Method A cross-sectional nationwide epidemiological study of the Iranian population, aged 18 years and older, designed to estimate the prevalence of psychiatric disorders and their association with some demographic factors. From 12,398,235 households residing in Iran, 7795 families selected by a randomized cluster sampling from 1559 clusters, 997 clusters were in urban and 582 were in rural areas, each cluster with 5 households were studied. The total number of the subjects, whom interviewed and completed Schedule for Affective Disorders and Schizophrenia (SADS)21 and also the epilepsy questionnaire, were 25,180 subjects in year 2001. The response rate was 90%. The widely known instrument, the structured interview of SADS, used to obtain psychiatric disorders by Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria.22 It is a structured instrument that ascertains the diagnosis of psychiatric disorders. Its reliability and validity have previously been reported.23,24 Based on prior studies25,26 the questionnaire made. Its’ face validity was confirmed by three

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Table 1 Prevalence of epilepsy by sex, age group and marital status Variable

N

Percentage

Significance

Sex M F T

199 255 454

1.6 2 1.8

X2 = 7674, d.f. = 1, P < 0.006

Age 18—25 M F T

75 67 143

1.9 1.8 1.8

X2 = 7.25, d.f. = 4, P < 0.12 a X2 = 5.27, d.f. = 4, P < 0.26 b X2 = 5.48, d.f. = 4, P < 0.241 c

26—40 M F T

52 83 138

1.3 2 1.7

41—55 M F T

42 69 112

1.5 2.4 2

56—65 M F T

20 23 43

1.9 2.6 2.2

+65 M F T

10 13 23

1 1.8 1.4

70 51 123

1.7 1.6 1.7

126 185 314

1.5 2.1 1.8

0 3 3

— 3.5 2.5

3 15 18

4 2.7 2.8

Marital statues Single M F T Married M F T Separated or divorce M F T Widow/widower M F T

X2 = 3.87, d.f. = 3, P < 0.275 a X2 = 4.97, d.f. = 3, P < 0.17 b X2 = 4.712, d.f. = 3, P < 0.19 c

M, male; F, female; T, total. Discrepancy between total numbers and sum ups of male and female numbers are due to the missing data (N = 25,180). a Statistical analysis in total group. b Statistical analysis in male subjects. c Statistical analysis in female subjects.

specialists (two neurologists and one psychiatrist) and a pilot study was done. One hundred screened individuals (50 positives and 50 negatives) randomly assessed by a psychiatrist who was blinded to the screening results. He conducted a complete history

and systematic and neurological examination, and review of prior medical records. The questionnaire demonstrated 90% specificity and 78.5% sensitivity. The interviewers trained to use it. The subjects comprehend questions well.

Prevalence of epilepsy and psychiatric disorders in Iran

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Table 2 Prevalence of epilepsy by type of occupation, education and residential area Occupation

N

Percentage

Significance

Employed M F T

143 16 160

1.4 1.3 1.4

X2 = 18.42, d.f. = 3, P < 0.000 a X2 = 7.16, d.f. = 4, P < 0.12 b X2 = 29.68, d.f. = 4, P < 0.0000 c

Students M F T

12 12 24

1.3 1.5 1.4

7 1 8

1.2 0.8 1.1

Householder M F T

0 211 211

— 2.2 2.2

Unemployed M F T

37 14 52

3 1.9 2.7

Education Illiterate M F T

17 11 28

1.1 1.1 1.1

Primary and secondary school M 135 F 144 T 283

1.5 1.9 1.7

Higher educated M F T

47 99 147

2.2 2.6 2.5

125 146 274

1.6 1.9 1.7

74 109 185

1.6 2.3 1.9

Retired M F T

Residential area Urban M F T Rural M F T

X2 = 7.69, d.f. = 2, P < 0.021 a X2 = 12.51, d.f. = 2, P < 0.002 b X2 = 23.34, d.f. = 2, P < 0.000 c

X2 = 0.001, d.f. = 1, P < 0.97 a X2 = 5.49, d.f. = 1, P < 0.24 b X2 = 1.76, d.f. = 1, P < 0.18 c

Discrepancy between total numbers and sum ups of male and female numbers are due to the missing data. M, male; F, female; T, total (N = 25,180). a Statistical analysis in total group. b Statistical analysis in male subjects. c Statistical analysis in female subjects.

Lifetime prevalence was used and active and inactive epilepsy were considered together. Seizures were classified based on self- and other informant relative-reported clinical symptoms. Epilepsy defined as two or more seizure of nonfebrile, unre-

lated to any acute medical disorder, intoxication or withdrawal of alcohol or drugs, head trauma, central nervous system infection and stroke. The lifetime prevalence is the proportion of persons manifesting a disorder during the period of their

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Table 3 Lifetime history of psychiatric disorders among subjects with a positive history of epilepsy (N = 25,180) The psychiatric disorders Major depressive disorder Minor depressive disorder Bipolar Mood disorder-I Bipolar Mood disorder-II Panic Disorder General Anxiety Disorder Obsessive compulsive disorder Specific phobia Social phobia Somatization disorder Post traumatic stress disorder Schizophrenia Suicidal attempt

Male (%)

Female (%)

Total n (%)

Lower

Upper

General population of Iran* (%)

7.5 0.5 0.5 4 4.5 1 6 3 1.5 1.4 1 2 5

13.3 1.6 0.8 4.3 7.8 2.7 7.1 6.7 4.7 2 2.7 3.1 10.2

49 6 3 19 29 9 30 23 15 8 9 12 37

2.9 2.1 3.3 3.9 3.6 1.1 2.8 2.9 2.5 5.3 2.7 7.7 4.6

5.3 11.4 41.2 10.3 8.0 4.2 6.1 7.0 7.4 24.5 10.8 27.8 9.4

2.98 0.33 0.1 0.7 1.49 1.33 1.8 1.86 0.82 0.18 0.98 0.25 1.4

(10.7) (1.3) (0.7) (4.1) (6.3) (2.0) (6.5) (5.0) (3.3) (1.7) (2) (2.6) (8.1)

95% CI

The subjects may suffer from more than one disorder. * Mohammadi MR, et al. Clin Pract Epidemol Ment Health. 2005 Sep 26;1:16.

life up to the survey date. We excluded subjects who had experienced only a single seizure. This research’s data collected through face-toface interview conducted by 250 experienced clinical psychologists, who completed a rigorous program of training to administer the SADS reliably, employed throughout country and the diagnosis was made based on diagnosis of DSM-IV classification. The variables of age, genders, marital status, type of occupation, educational level and residency in urban or rural area were examined as associated factors. A more detailed discussion of the results about other psychiatric disorder is presented in the overview of the survey.27 Procedure for carrying out the study were approved and executed in accordance with institutional requirements for the protection of human subjects. Informed consent was obtained from each respondent prior to the interview. Chi-square test used to examine the association of epilepsy with the mentioned factors in each total, male and female groups; separately.

Results The sample consists 25,180 subjects having 18 years and older. The mean and standard deviation of their age are 37.2 and 16.6 years, respectively. 50.3% of them were men and 49.7% were women. 29.13% were single and 67.45 were married, the others were separated or divorced (0.48%) and widow (2.54%), undetermined (0.40%). The prevalence of epilepsy was 1.8% in the country. Epilepsy was more common in females, unem-

ployed and higher educational level. It was not significantly associated with the age group, marital status, and residential areas. However, the prevalence was more in age groups of 56—65 and 41—55. The prevalence of epilepsy in widow/widower and separated subjects was more than among single or married groups. However, the maternal status and frequency of epilepsy was not significant associated. The most common psychiatric disorders in subjects with epilepsy were major depressive disorder and obsessive compulsive disorder. The rate of lifetime suicidal attempt was 8.1%. Table 1 shows the association of epilepsy by sex, age group and marital status. The association of epilepsy by occupation, education, and residential areas are shown in Table 2. The unemployed category was compared with the other occupational categories in the epileptic subjects. Lifetime history of psychiatric disorders among subjects with a positive history of epilepsy is shown in Table 3.

Discussion This study shows that epilepsy is a common neurological condition in the Iran. Despite epilepsy being amongst the most common serious neurological conditions, the reported prevalence figures vary widely. This can be due to differences in case ascertainment, differences in age groups studied and differences in the location of the study and on the definitions used. It is more common in female than males. Some of the prior studies have shown that it was more common in female than male.8—10 In a study in London there was not difference between males and females.11

Prevalence of epilepsy and psychiatric disorders in Iran The prevalence of epilepsy among different age group was not different. Another door-to-door study also showed that it was more common in younger ages and older ages.8 Epilepsy in higher educational level was more common than the lower ones. It is inconsistence with many studies that shown epilepsy is associated with poor academic achievement.12—15 It is possible that educated people are more aware and concern about the symptoms and seeking the treatment in Iran. Type of occupational status was associated with epilepsy in male and also in total groups. However, it was not associated in female group. The most common type of occupation was ‘‘unemployed’’. It is in accordance with the prior studies.13—17 Marital status was not associated with epilepsy. However, some prior studies have shown the reduced rate of marriage in patients with epilepsy.16,17 The prevalence was not associated with residential areas, such as in India.6 The most common psychiatric disorders were major depressive disorder, obsessive compulsive disorder, panic disorder and bipolar mood disorder. The rate of suicidal attempt was relatively high. However, the most common rates in the general population of Iran were major depressive disorder, phobic disorders, obsessive compulsive disorder and panic disorder.27 The prevalence of psychiatric disorders in the community in the current study were: major depressive disorder, 2.98%; bipolar mood disorder, 0.96%; schizophrenia, 0.25%; panic disorder, 1.49; generalized anxiety disorder, 1.33; obsessive compulsive disorder, 1.8%.27 It seems that the rates in the epileptic subjects are more than the rates in the general population.

Limitations It is necessary to mention some points: although the response rate was high but some subjects probably have concealed their epilepsy. For example, among young adult women because of their concern with possible effect of it’s revealing on their marriage prospects or because of a social stigma which is associated with epilepsy. Current study did not address issues such as taking antiepileptic medication, active or inactive epilepsy, neurological evaluation, or medical records and IQ. Another limitation is that, remembering past has some difficulties and it may under report the conditions of the past. Also, we know that a substantial proportion of the people with relatively uncommon disorders like schizophrenia are already long-term residents of mental hospitals, and thus not included in the study. Less severe episodes of symptom ear-

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lier in life may be forgotten. Forgetting episodes may not be only a matter of forgetting, but also a result of the processing of the significance and meaning of the symptoms with time. It is questionable whether symptoms that today are rated as medical would now be understood and reported as nervous symptoms. The importance of lateralization of focus in patients with temporal lobe epilepsy and psychosis should be noted.28 It is postulated that left- and right-sided seizure foci are more likely to be associated with a schizophrenia-like and manic-depressive presentations, respectively. DSM-IV criteria are not based of etiology and are not exclusive to epilepsy. Also, the clinical manifestations of psychiatric disorders in patients with epilepsy may be different from those of the psychiatric disorders in nonepileptic patients. The differentiation between some emotional associated feature of epilepsy and anxiety disorders such as panic disorder is diagnostically challenging and some may experience emotional manifestation as their symptoms.

Recommendation The diagnosis of epilepsy is, in essence, clinical and is based upon the medical history, physical and neurological examination and the history of the epileptic seizures and their phenomenology and EEG. In communities the direct screening with an interview may be the primary tool to identify cases. It may be desirable to use an intensive case-finding strategy involving multiple avenues (e.g. direct screening with an interview; reviews of medical, laboratory or other records; contacts with other informants). In the current study, the diagnosis of epilepsy was possible, no definite. Also, it was included active and inactive epilepsy.

Acknowledgements We appreciate the contributions of Dr. Kazem Mohammad, Haratoon Davidian, Ahmad Ali Noorbala, Hossein Malekafzali, Hamid Reza Naghavi, Hamid Reza Pouretemad, Seyed Abbas Bagheri Yazdi, Mehdi Rahgozar, Javad Alaghebandrad, Homayoon Amini, Emran Mohammad Razzaghi, Mohammad Reza Rostami, Saeed Madani, Drs. Tavakoli and Mohammad Taghi Joghatai, Ms. Afsanah Baghaie and all the headquarters and also the Medical Commission of National Scientific Research Council, National Research Center for Medical Sciences of Iran, Deputy for Research and Technology, Health Deputy, Medical Commission of National

482 Research Council, The Welfare and Rehabilitation Sciences University, Deputy for Prevention of Welfare Organization, Psychiatric Department of Roozbeh Hospital and 250 clinical psychologists and experts who assisted us in conducting this national study.

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