Abstract
The aim of the present study was to estimate the co-morbidity of migraine and major depression in the Turkish population. The households were selected randomly from all district areas. The study included 947 subjects aged ≥ 18 years. The diagnosis of migraine was made according to the criteria of the International Headache Society. The diagnosis of major depression was made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria. Migraine was identified in 163 subjects. Major depression was identified in 155 subjects, and in 53 subjects with migraine. The lifetime prevalence of major depression was approximately three times higher in persons with migraine in this Turkish population.
Introduction
The term ‘co-morbidity’ refers to the coexistence of two conditions within the same individual (1). Co-morbidity studies are important to illuminate aetiologies of the diseases and to develop new treatment modalities. Possible explanations for co-morbidity include: (i) co-morbidity can be found coincidentally or can arise from selection bias of the population; (ii) one condition can be the reason for the other condition; (iii) the conditions may be related to shared environmental or genetic risk factors; and (iv) environmental and genetic risk factors may produce a brain state that gives rise to both conditions (2).
Migraine and major depression are common disorders that have a large socio-economic impact and significant adverse effects on the quality of life. There are significant similarities between migraine and major depression. Both of them are frequently seen in the young adult population and females, their prevalences are close to each other, age of onset is similar and treatment of the both diseases includes anti-depressive agents. A possible relationship between migraine and depression has been argued since the days of Liveing (3). Clinical and population-based studies consistently demonstrate that there is an association between migraine and major depression (4–16).
Most previous studies of co-morbidity of migraine and major depression were based on only a few communities. Genetic or environmental causes are accepted as important in co-morbidity. The aim of this study was to estimate the co-morbidity of migraine and major depression in the Turkish population and to compare it with the other communities.
Methods
The study was performed to determine migraine prevalence, clinical characteristics of migraine and co-morbidity of migraine and major depression. The migraine prevalence and clinical characteristics part of the study was previously reported (17). In this report, we present the results regarding the co-morbidity of migraine and major depression which composed the other part of the study.
The study was cross-sectional and questionnaire-based. It was performed in Sivas, Turkey. The population of Sivas was 224 103 residents according to the 1997 census. The city centre consisted of 62 district areas. The size of the sample from each district was determined according to the size of the district area. The households were selected from the table of random numbers, from all district areas. Household interviews were conducted between January and June 1999. Information about the content of the study was given to each person and oral informed consent was obtained from subjects. Sixteen persons did not accept interview and they were excluded from the study and all statistical analysis. The study was terminated when the number of participants reached the target value in each area. Interview was conducted face to face by a neurologist and a psychiatrist. The study included 1320 participants, but 373 under 18 years old were not questioned concerning depression. Therefore, 947 participants were questioned concerning co-morbidity of migraine and major depression. In this co-morbidity study, data about migraine and demographics obtained from individuals < 18 years old were not used for any statistical analysis.
The questionnaire consisted of three parts, including questions relating to demographic data, headache and depression. The demographic data included age, educational level, economic and marital status. All participants were asked ‘do you suffer from headache?’ If the participant suffered from headache, both headache and major depression questions were asked, but if not, only major depression questions was asked.
Migraine diagnosis
Each subject with headache was questioned about the characteristics of the headache, as follows: the age of onset, the number of the attacks, frequency (one to two times weekly, once every 2 weeks, once a month or less often), duration (0–4 h, 4–24 h, 24–72 h or> 72 h), quality of pain (pulsating, pressing, tightening), location (unilateral, bilateral or variable), severity (mild, moderate or severe), aggravating factors (emotional stress, fatigue, sleeplessness, hunger, strong odours, travelling, physical activity, foods), ameliorating factors (dark, silent room, sleep), prodromal symptoms (fatigue, indigestion, irritability, depression, hunger, coldness), associated symptoms (nausea, vomiting, photophobia, phonophobia, osmophobia, blurring of vision) and aura (visual, motor, sensory). Migraine diagnosis was made according to the criteria of the International Headache Society (IHS) (18). If the answers were compatible with IHS migraine criteria, the person was classified as ‘with migraine’. Subjects with migraine were classified as ‘without aura’ or ‘with aura’, according to IHS code 1.1 and 1.2. Others were classified as ‘without migraine’.
Major depression diagnosis
Diagnosis of major depression was made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) Criteria (19). The major depression questionnaire was designed in accordance with DSM-IV, and included nine questions. The questions were: (i) do you have periods of depression which last for more than 2 weeks without any apparent cause, for most of nearly every day?; (ii) do you have difficulty in being interested in hobbies or activities that you used to enjoy nearly every day? (iii) have you experienced any weight gain or loss (5% of body weight) while not dieting or attempting to gain weight? (iv) have you experienced any change in your sleeping pattern (too little or too much) every day? (v) do you feel agitated or depressed nearly every day? (vi) do you have fatigue or loss of energy nearly every day? (vii) do you feel worthlessness or excessive guilt nearly every day? (viii) is it difficult for you to concentrate or make decisions about most things nearly every day? and (ix) do you repeatedly have thoughts about death, suicide, or have you made a suicide attempt? Major depression is defined as the presence of at least five symptoms from a list of nine symptoms which occurred within the same 2-week period, with at least one of the symptoms pertaining to a depressed mood or loss of interest and pleasure.
Statistical analysis
Data were analysed with the SPSS (Statistical Package for the Social Sciences for Windows) program. χ2 values were calculated from 2 × 2 cross-tabulations of binominal parameters. Odds ratio (OR) values were calculated by multivariate logistic regression analysis.
Results
The socio-demographic characteristics of the sample are presented in Table 1. There were 395 males (41.7%) and 552 females (58.3%). The mean age was 40.25 ± 15.23 years in males, 37.53 ± 14.81 years in females.
Socio-demographic characteristics of the sample
The lifetime prevalence of migraine was 10.37% (41 subjects) in males and 22.10% (122 subjects) in females. The lifetime prevalence of migraine was found to be higher in females than in males (OR = 2.45 (95% CI 1.67, 3.58), χ2 = 22.20, d.f. = 1, P = 0.00). The lifetime prevalence of major depression was 8.86% (35 subjects) in males and 21.73% (120 subjects) in females. The lifetime prevalence of major depression was found to be significantly higher in females than in males (OR = 2.85 (95% CI 1.91, 4.29), χ2 = 27.89, d.f. = 1, P = 0.00).
The lifetime prevalence and risk of major depression were significantly higher in subjects with migraine when compared with subjects without migraine (Wald χ2 = 26.0, P = 0.00). The lifetime prevalence and risk of major depression were significantly higher in migraine with aura than in migraine without aura (Wald χ2 = 14.59, P = 0.00). The lifetime prevalence and risk of major depression were significantly higher in migraine with aura than in subjects without migraine (Wald χ2 = 17.22, P = 0.00). Table 2 shows the lifetime prevalences and risk values for major depression in patients with migraine and in subtypes of migraine.
Major depression prevalence and odds ratio (OR) values in subtypes of migraine
∗Sex-adjusted OR, from multivariate logistic regression.
It was found that the lifetime prevalence of major depression was similar in males with migraine (31.70%) to females with migraine (32.78%) (χ† = 0.016, d.f. = 1, P = 0.898). The risk of major depression in migraine was higher in males with migraine than in females with migraine (OR = 2.52 (95% CI 1.68, 3.79), χ2 = 24.48, d.f. = 1, P = 0.000). Table 3 presents lifetime prevalences of major depression and risk values according to gender.
Lifetime prevalence of major depression in migraine and odds ratio (OR) according to sex
∗From χ2 test.
†From multivariate logistic regression.
Discussion
Previous population-based studies revealed that the lifetime prevalence of migraine was approximately 6–14% in males and 12–18% in females (20–22). The results of the present study show that lifetime prevalence of migraine was 10.37% in males, 22.10% in females. These values are moderately higher, because our sample population was ≥ 18 years of age; migraine prevalence is increased after puberty. Indeed, lifetime migraine prevalence was found to be 7.9% for males and 17.1% for females, including under 18-year-old individuals (17). The results regarding the Turkish population were similar when compared with other population study results.
The lifetime prevalence of major depression is approximately 10–15% and is two times higher in females than in males. The lifetime prevalence of major depression is reported as 5–12% in males, 10–25% in females (23). In our study we found that lifetime major depression prevalence was 8.86% in males and 21.73% in females. These results of the present study are in accordance with those of other studies.
Our results suggest that migraine is associated with major depression. Major depression was more common in subjects with migraine (32%) than in subjects without migraine (13%). Risk of major depression in patients with migraine was 2.8 times higher. This result confirms those of other studies on the association between migraine and major depression (4–6, 9–11, 24, 25). All reports showed two to four times increases in the risk of depression in persons with migraine. These studies consistently demonstrate co-morbidity of migraine and major depression across studies, despite the variations in geographical, genetic, cultural, and environmental factors, methodologies, age ranges and sex distributions of samples and time period prevalence. These variations in studies may explain the small differences in the magnitude of the risk value. The results are compared in Table 4.
Association between migraine with depression–population studies
The prevalence of major depression in persons with migraine was approximately equal in both sexes: 31.7% in males, 32.7% in females. However, these values were not close in both genders in people without migraine. Furthermore, depression prevalence showed two to three times predominance in females. This implies that major depression risk in male patients increased. In this study the major depression risk was also found to be 2.5 times higher in males with migraine than in females with migraine (see Table 3).
The two most common subtypes of migraine are migraine with and without aura. Persons with each subtype showed higher value of prevalence and OR of major depression than persons without migraine. The prevalence of major depression in those with migraine with aura was considerably higher than in those with migraine without aura. The OR of major depression was 4.4 in migraine with aura, 2.5 in migraine without aura. This result confirms the other reports detecting a higher risk in migraine with aura. The differences between the two subtypes could also be attributed to their differences in severity; migraine with aura may represent a more severe condition, thereby exhibiting stronger associations with major depression than migraine without aura. The other possible reason may be related to the presence of different genetic characteristics between the subtypes of migraine. Genetic epidemiological and molecular studies verify this difference (26, 27).
Migraine is a multifactorial disease. In multifactorial traits, if there is a unequal sex incidence, the risk is higher for the low sex incidence group. The higher risk is present in the severe type of disease, also (28). For migraine, the male population has less sex incidence and migraine with aura is the severe form. The increased risk in male patients and patients with migraine with aura can be related to genetic transmission.
One of the limitations of this study was the small sample size. This limitation did not allow further statistical analysis of demographic factors.
In conclusion, previous population-based studies reveal that the prevalence of major depression is approximately three times higher in those with migraine. Our findings confirm previous studies on the association of migraine and major depression. Our study suggests that the lifetime prevalence of major depression is 2.8 times higher in those with migraine in the Turkish population. As mentioned above, co-morbidity of migraine and major depression is important for the Turkish population, as for other countries. Little difference of prevalence rates and risk values can be related to genetic, cultural, and environmental factors, age range, sex distribution of samples and time period of prevalence. In spite of all differences in environmental factors, there is association between migraine and major depression in all studies, and its risk value results have close resemblance. Therefore, biological factors such as the neurochemical system or shared genetic predisposition may be responsible and more important for the risk of major depression in persons with migraine.