ORIGINAL PAPER BIPOLAR DISORDER AND OTHER ASSOCIATED FACTORS IN POSTNATAL DEPRESSION Ng CG*, Aida SA*, Aizura SA**, Salina M*, r Zuraida Z*, Koh OH* *Department of Psychological Medicine, Faculty of Medicine, University Malaya**Department of Obstetric and Gynecology, Faculty of Medicine, University Malaya Abstract Postnatal depression is common and affects 10-15% of postpartum women. While there are many studies on the depressive episode in the postnatal period, its association with the bipolar spectrum disorder is often go unrecognized and undiagnosed. Objective: To study the rate of bipolar spectrum disorder in mothers presented with postpartum depression and its associated factors. Method: This is a cross sectional study on the women who visited the postnatal clinic in University Malaya Medical Centre. Subjects who consented were asked to complete a short questionnaire looking at the socio-demographic details and asked to answer the Multidimensional Scale of Perceived Social Support (MSPSS), Mood Disorder questionnaire (MDQ) and Edinburgh Postnatal Depression Scale (EPDS) whish assess the perceived social support and mood disorder. Result: A total of 93 women were recruited into the study. Independent t-test and stepwise regression analysis identified that unemployment and baby with health problem were the only associated factors for postnatal depression. 28.6% of the mother with possible postnatal depression (EPDS 12) might have bipolar spectrum disorder (MDQ 7). Conclusion: Postnatal depression as part of bipolar spectrum disorder needed additional attention. Postnatal check with screening tools may help to identify mood disturbance in postpartum women. Keywords: Postpartum depression, bipolar spectrum, screening instrument. Introduction Childbirth has been recognized to be a common precipitant of mental illness for mothers. It affects almost 10% of all mothers.1,2 A meta-analysis of 59 studies reported a prevalence of 13% with most cases starting in the first 3 months postpartum.3 The similar result was reported in the earlier studies that psychiatric disorder is common in the months following childbirth.2,4,5,6,7 Depression is one of the common mental illnesses identified in the postnatal period.2 The occurrence of depressive illness following childbirth can be detrimental to the mother, her marital relationship and children. It can have adverse long term effects if untreated. 1
The lifetime prevalence of bipolar spectrum disorder has been found to be between 2.6% and 6.5%.8 While there are many studies on the depressive episode in the postnatal period, its association with the bipolar spectrum disorder is often go unrecognized and undiagnosed.9,10 Recent study found that misdiagnosis of bipolar disorder as unipolar depression is a well-documented phenomenon in the psychiatric literature. The study revealed that out of 56 women referred with the diagnosis of postpartum depression, more than half actually had bipolar disorder.11 Another study looking into the recurrent nature of postpartum episode in bipolar disorder found that the polarity of postpartum episode was exclusively depressive.12 In fact, it is found that women with manic depression are more likely to relapse in the postpartum period.13,14 The risk of relapse during the postnatal period range between 20% and 50%.14-17 One way of increasing identification of bipolar disorder in mother with postnatal depression is the use of screening instrument. A brief and easy-to-use screening instrument for bipolar spectrum disorder is the Mood Disorder Questionnaire (MDQ).18 In regard to the postnatal depression, Edinburgh Postnatal Depression Scale (EPDS)19 is commonly used in the clinical and research settings. The aim of the study is to identify the rate of bipolar spectrum disorder in mothers presented with postnatal depression by using MDQ and EPDS. The authors also examine the associated socio-clinical features for the mood episodes. Method Sampling The study was conducted at the postnatal clinic of University Malaya Medical Centre (UMMC). UMMC is a teaching hospital situated in Kuala Lumpur. Its patient catchments area includes those living in Kuala Lumpur and also Petaling Jaya, Selangor. Most of the patients are urbanized and affluent. The obstetrical unit of the Department of Obstetrics and Gynecology is situated in the maternity block of UMMC. The postnatal clinic is located at the ground floor of the building. All the mothers delivered uneventfully in UMMC are given an appointment to come back for checkup six weeks after delivery on Wednesday or Friday afternoon from 2pm till 4.30pm. Mothers with various complications are given earlier appointment to revisit clinic on Monday, Tuesday or Thursday afternoon. The average patient load in a month is about 250 visits. The postnatal clinic is conducted combined with Paediatric Unit in assessing the newborn babies. Study Design This is a cross sectional study involving all mothers who attended the postnatal clinic in UMMC from 1st March to 31st March 2009. Ethical approval was obtained from the Medical Ethical Committee of UMMC before study commencement. All patients who attended the postnatal clinic of UMMC during the study period were approached. Consent was obtained. Those who consented were recruited and asked to complete a short questionnaire designed by the study team looking at the socio-demographic details and asked to answer the MDQ and EPDS. The social support is assessed with Multidimensional Scale of Perceived Social Support (MSPSS).20,21 Patients who were unable to answer the questionnaires due to lack of understanding or illiteracy were 2
assisted by the researchers to complete them. Instrument The MDQ screens for a lifetime history of a manic or hypomanic syndrome by including 13 yes/no items derived from both the DSM IV criteria and clinical experience. Finally, the level of functional impairment due to these symptoms is queried on 4 point scale. A MDQ screening score of 7 or more was chosen as the optimal cutoff by the author in the original report, as it provided good sensitivity (0.73, 95% CI = 0.65-0.81) and very good specificity (0.90, 95% CI = 0.84-0.96).18 In addition, all the symptoms must have occurred at the same time and the symptoms have moderate to severely affected the person s function. The EPDS is a 10 items self rated scale, which was derived from the earlier work of Snaith. It was reported to have satisfactory validity, split half reliability and was also sensitive to changes. The scale was fully acceptable to the child bearing women and usually completed within 5 minutes. Based on the data in the author s original paper, it was suggested that women scored above a threshold of 12/13 were more likely to be suffering from a depressive illness of varying severity. It was recommended that score below cut off should not be taken to indicate the absence of depression.19 The MSPSS developed by Zimet GD in 1988 (Zimet et al, 1988). It is a instrument specifically addresses the subjective assessment of social support adequacy. It is a 12 item instrument designed to assess perceptions of social support from three specific sources: family, friends and significant other. The MSPSS assess the extent to which respondents perceive social support from each of those sources and is divided into three subscales: family (item 3,4,8,11); friends (item 6,7,9,12) and significant other (item 1,2,5,10). It uses a 7- point Likert type response format (1=very strongly disagree, 7=very strongly agree) (Fisher J, Corcoran K, 1994). The MSPSS has excellent internal consistency, with alphas of 0.91 for total scale and 0.90 to 0.95 for the subscales. The author claim good test-retest reliability, factorial, concurrent and construct validity.20 Analysis Data were analyzed using Statistical Package for Social Sciences Version 13.0. To test the statistical significance, independent t test was used. All the test of significance was two-tailed, with an alpha level of 0.05. Result A total of 93 mothers consented and included in the study. 3
Table 1 Socio-demographic characteristics of the subjects Mean S.D. Age (year) 30.4 5.2 Race Malay Chinese Indian Others Employment Education Primary Secondary Tertiary N % 56 16 19 2 26 67 2 49 42 60.2 17.2 20.4 2.2 28.0 72.0 2.2 52.7 45.2 Pregnancy Complication during delivery Healthy baby Placing of baby First Second Third Fourth Fifth and above Breast feeding Fully breast feed Never breast feed Mixed with bottle feeding 30 63 41 52 84 9 45 24 16 5 3 40 5 48 32.3 67.7 44.1 55.9 90.3 9.7 48.4 25.8 17.2 5.4 3.2 43.0 5.4 51.6 Table 1 shows the descriptive characteristics of the 93 samples. The mean age of the subjects was 30 years old (range = 18-46). Most were Malay and achieved at least secondary education. Two third of the subjects were employed. Table 2 Clinical characteristics of the current pregnancy N % Duration after delivery Less than 6 months 6 months and above 32 61 34.4 65.6 History of mental illness History of medical illness Substance use Previous life events 1 92 7 86 1 92 20 73 1.1 98.9 7.5 92.5 1.1 98.9 21.5 78.5 Planned pregnancy Complication during 46 47 49.5 50.5 Table 2 shows the descriptive characteristics of the pregnancy. One third of the subjects developed complication during the pregnancy and 4
came for early follow up in the postnatal clinic (less than 6 weeks). Half of the pregnancies were unplanned. Slightly more than half of the subjects had complication during delivery and 9 babies had health problem. Most were first baby for the subjects. Only 40% of the subjects were fully breast feeding. Table 3 EPDS and MDQ score of the subjects One fifth of the subjects experienced certain life events prior to the delivery. The mean MSPSS scores of the subjects was 44.5 + 11.6(SD). Overall, most of the subjects perceived to have good social support based on the high MSPSS. N Mean S.D. Cutoff Point n % EPDS 93 3.9 4.0 7 7.5 (cp = 12) MDQ (cp = 7) 93 1.7 2.1 4 4.3 cp = cutoff point. Table 3 shows the description of the EPDS and MDQ scores of the subjects. On average, the subjects had low EPDS and MDQ scores. 7 mothers scored above the threshold value of 12 in EPDS and 4 mothers had MDQ scores above the cutoff value of 7. Table 4 Distribution of MDQ scores in samples with EPDS above the threshold value. MDQ score n % 0 1 14.3 1 1 14.3 2 2 28.6 3 0 0 4 0 0 5 1 14.3 6 0 0 7 0 0 8 2 28.6 Table 4 shows the distribution of the MDQ scores among the 7 subjects with EPDS score above the cutoff value of 12. 2 women scored above the MDQ cutoff value of 7. 5
Table 5 Relationship between socio-clinical factors with EPDS score Category Mean t P 95% CI Age Less than 30 30 and above 3.89 3.88 0.01 0.01 1.00-1.63, 1.65 Race Malay n Malay 3.36 4.68-1.32-1.58 0.12-2.97, 0.34 Employment 5.42 3.28 2.14-2.37 0.02* -5.90, -0.51 Education Secondary and lower Higher than secondary 3.76 4.02-0.26-0.31 0.76-1.91, 1.39 Duration delivery after Less than 6 weeks 6 weeks and more 3.53 4.07-0.54-0.62 0.54-2.26, 1.19 Planned pregnancy 3.70 4.06-0.36-0.45 0.66-2.01, 1.27 Complication during pregnancy Complication during delivery Healthy baby Placing of baby First child Second and above 3.70 3.99-0.29-0.30 0.76-2.02, 1.49 4.20 3.63 0.56 0.68 0.50-1.09, 2.21 3.57 6.78-3.21-2.37 0.02* -5.90, -0.51 3.91 3.85 6
0.06 0.07 0.95-1.58, 1.70 Breast feeding Fully breast feed Mixed or never 3.69 4.04-0.35-0.42 0.68-2.00, 1.30 Previous events * p < 0.05 life 4.90 3.60 1.30 1.30 0.20-0.68, 3.28 Discussion UMMC is one of the leading teaching and tertiary referral centre in Malaysia. It is located in Kuala Lumpur, the capital of the nation. Based on the sources from Department of Statistics and assumptions derived from existing number of housing units in Kuala Lumpur, it is estimated that the population in 2000 was 1.42 million. It comprised mostly of Chinese (43%), followed by Malay (38%) and Indian (10%)22. However in this study majority of the subjects were Malays (60.2%) and less than 20% are Chinese. This could be explained with the low birth rate23 and preference to deliver in the private hospital among the Chinese in the region. The original English version of MSPSS was translated into Malay and validated among a group of medical students by the authors.21 The scale was used to assess the degree of perceived social support in the subjects. Overall, the subjects had good perceived social support in the study. The EPDS was used to examine the depression in the subjects. Based on the original paper by the authors of EPDS, women who score above a threshold of 12 were more likely to be suffering from depressive illness.19 In this study, there was 7.5% of the mothers score above the cutoff point. It is slightly lower than the previous studies which reported 10-15% of the mothers experience depressive illness after childbirth.1-6,24 It shows that the prevalence of depressive illness varies according to the study setting, design and threshold point of the questionnaire used. MDQ was used to screen for bipolar spectrum disorder in the study. 4.3% of the mothers scored above the cutoff point of 7 as suggested by the authors of the MDQ. It is within the range of prevalence reported in the previous study.8 It is commonly known that depression arises when a vulnerable individual confronts adversity.25 Childbirth is suggested as a uniquely potent precipitant of affective disorder in mothers.16 There were many literatures looking into the occurrence of depressive disorder in postnatal period. In contrast, study on the postpartum depression as part of bipolar spectrum disorder is limited.9,10 In this study, the authors aimed to study the rate of bipolar in women presented with postnatal depression. Lane et al (1997)9 reported a relationship between EPDS and High scores at day 3 and week 6 among mothers. Glover et al (1994) failed to find an association between the scales.26 In this study, there was 28.6% of the subjects with possible postnatal depression (EPDS 12) might have bipolar spectrum disorder (MDQ score 7). This finding is similar to the result of 7
previous study which reported the risk of recurrence of bipolar illness after childbirth is thought to be about 25%.16,17 Hunt et al (1995)14 reported that only 31% of deliveries leading to relapse of mother with a past affective episode. It was explained that childbirth might only hastened the onset of an inevitable affective illness and some bipolar patients are particularly prone to becoming ill after childbirth. In other words, only mother with inherited diathesis may express itself as vulnerable to life events such as childbirth. The concept of childbirth may be a uniquely potent precipitant for women with a moderate genetic or constitutional predisposition to affective disorder was not fully accepted by all researchers. In a different view, there is suggestion that puerperal psychosis in some proportion may have a different illness from that which is ordinarily seen as non-postpartum mania.13,27 Besides looking into the rate of bipolar spectrum disorder, the authors also examined the associated socio-clinical factors of postpartum depression in the study. Varieties of risk factors in postpartum depression such as single status, unplanned pregnancy and other social factors were reported in previous studies.28-38 In this study, unemployment and baby with health problem were the only two significant associated factors identified to be associated with relatively high EPDS scores. It was similar with the finding of a previous study where Warner et al (1996)36 reported that factor associated with high EPDS scores at 6-8 weeks after delivery is unemployment.30 Baby with health problem is obviously a risk for depression for mothers. Poor child health is an added stress and make depression manifest in individuals with an increased vulnerability to depression.28,30 Johnstone et al (2001)37 suggested that most obstetric factors during pregnancy and birth do not significantly increase risk for depression. Instead, the importance of psychosocial risk factors for postnatal depression is emphasized. This is supported by the findings in the current study where complication during delivery or pregnancy do not associated with depression in mothers. Conclusion Postnatal depression as part of bipolar spectrum disorder needed additional attention and further studies. Postnatal check with screening instrument may help to recognize mood disturbance in mothers. Early identification and prompt treatment of postnatal mental illness will reduce the adverse effect on the mother, child and family. Acknowledgement We would like to take this opportunity to thank all the staffs in the postnatal clinic, UMMC for helping in the data collection for the study. Reference 1. Kendell RE, Chalmers JC & Platz C (1987) Epidemiology of puerperal psychoses. Br J Psychiatry 150:662-73. 2. Kumar RE & Robson K (1984) A prospective study of emotional disorders in childbearing women. Br J Psychiatry 144:35-47. 3. O Hara MW & Swain AM (1996) Rates and risk of postpartum depression: a meta-analysis. Int Rev Psychiatry 8:37-54. 4. Cox JL, Connor Y & Kendell RE (1982) Prospective study of the psychiatric 8
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