Screening for lifetime bipolarity in women with perinatal depression: Need for clinical and research attention.

Sir,

Nearly one in seven women experience depression during the perinatal period.[1] While screening for depression is often recommended (Edinburgh Postnatal Depression Scale; [EPDS] ≥10) in the postpartum period, the bipolarity screen has received considerably less attention. With a community prevalence of up to 4%–5% (inclusive of bipolar spectrum), bipolar disorder (BD) is not uncommon. The course of BD, with usual onset in the early 20’s, is likely to overlap with periods of pregnancy and childbirths in affected women. Further, there is increased risk of reoccurrence of BD during pregnancy and postpartum period. This could be possibly due to hormonal changes, inflammatory processes, and sleep-disruption contributions. BD is likely to be misclassified as unipolar depression in nonspecialist/obstetric settings, leading to inappropriate treatment choices. A study among postpartum women (n = 10,000, 14% screen positive on EPDS) reported that a striking 22.6% (one in five) of those who screened positive for postpartum depression had BD diagnosis confirmed using Structured Clinical Interview for DSM-IV (SCID).[2] Thus, screening for bipolarity would assist in the identification of undiagnosed BD.[13]

There are two broad approaches (namely, diagnostic interviews versus screening questionnaires with follow-up/linkages) toward the identification of bipolarity. Screening questionnaires have the advantage of brevity and feasibility, and can be used to identify the cases for expert referral and/or diagnostic interview. Mood Disorder Questionnaire (MDQ) is the most widely used screening tool (13-item, self-report) with satisfactory psychometric properties (internal consistency: 0.69–91; test–retest reliability: 0.79–91) and has demonstrated some validity in pregnant and postpartum samples as well.[45] Since it assesses lifetime bipolarity rather than current symptoms, there is less concern that normal pregnancy-related changes would confound the results. Traditional scoring (cutoff ≥7 along with endorsement of two supplementary questions, i.e., symptoms cluster in same time and moderate/serious degree of impairment) has demonstrated an unacceptably low sensitivity in nonpsychiatric samples. Subsequent research found that MDQ sensitivity in obstetric samples can be improved by omitting one or both supplementary questions. Such modified scoring of MDQ (score ≥7; without supplementary questions) was found to have an excellent sensitivity (89%) and specificity (84%) among perinatal women in comparison to DSM diagnosis made by experienced psychiatrist.[4] More research is, however, required to further establish optimal scoring threshold. The WHO-CIDI-based BD Screening Scale (12-item) compares favorably to MDQ in view of its better sensitivity in nonpsychiatric samples;[6] but is not a self-report measure and lacks studies validating its use in perinatal samples yet. Finally, the use of structured diagnostic interviews (e.g., relevant module/s of SCID) is the gold standard which requires trained interviewers and can be reserved for all screen-positive cases.

From a clinical perspective, lifetime bipolarity screen (e.g., MDQ with scoring adjustment) can be routinely employed for all postpartum women.[3] Clinical attention toward bipolar postpartum depression by means of screening and timely referrals to psychiatrists would prevent complications associated with sub-optimal treatment, including suicidality, iatrogenic consequences of antidepressant monotherapy without concomitant mood stabilizer (e.g., inducing rapid cycling and sub-optimal treatment response), and help to improve outcomes in perinatal women with bipolarity. A simultaneous screen for depression and BD has been suggested, since it was found that one-third of potential BD cases is missed if bipolar screen is restricted only to women with current depressive symptoms (EPDS ≥10).[1]

Screening for bipolarity is especially warranted for women who screen positive for perinatal depression or anxiety disorder, women with risk factors for bipolarity such as early age of onset of prior depressive episodes or familial loading of BD. Screening is best done using patient self-report measures at the initial presentation during pregnancy and once again at the first follow-up visit in postpartum.[7] However, the lack of trained mental health nurses in obstetric clinics, the already overburdened health-care system, and the lack of validated screening tools in vernacular languages (e.g., Hindi) make screening for bipolarity practically difficult. Further, it has been recommended that a chosen screening tool should ideally be validated against a gold standard diagnostic assessment in that specific context (e.g., postpartum samples).

Finally, we wish to caution against a sole reliance on screening tools for diagnostic or treatment purposes and re-emphasize on their obvious limitations (e.g., higher sensitivity leading to detection of false positives). Those who screen positive in clinical-epidemiological research must undergo a diagnostic interview by a trained mental health professional. The screening services cannot have practical utility without an effective linkage to psychiatric services. The management must be initiated in accordance with evidence-based guidelines only after a formal diagnosis is made. A stepped-care approach would be useful which involves screening of the high-risk women as the first step, followed by linkage and referral to clinical-psychiatric services for diagnostic interview and expert management. Psychiatrists need to have collaborative initiatives for improving research, education, and service delivery for postpartum women at all levels of care.

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Conflicts of interest

There are no conflicts of interest.