Postpartum Depression and Its Threshold: EPDS, and What Falls Below It

7 min read日本語版あり
Audience
Parents within the first year postpartum, and their partners and family members
Target length
~1,500 words
Status
Draft v1 (translated from Japanese v1)
Original
../19_postpartum_depression.md

Lead

At the first checkup after discharge, you are handed a ten-item questionnaire. You answer questions about how you have been feeling over the past seven days. A score is calculated. If the score exceeds a certain number, you are referred for a follow-up conversation.

That questionnaire is the — the standard screening tool for postpartum depression used in most maternity care settings and municipal health programs in Japan.

When someone says "I scored a 9" or "I scored a 12," what does that number actually mean? Does falling below the threshold mean you are fine? Does crossing it mean you have postpartum depression? And is there suffering that exists somewhere else entirely — outside what the score measures?

This article examines the EPDS, what its thresholds clinically mean, how common postpartum depression actually is, and what to do when the score comes back low but the difficulty persists.

What the EPDS Is — Back to 1987

The EPDS was published in 1987 by Cox, Holden, and Sagovsky in the British Journal of Psychiatry [1]. It is a ten-item self-report questionnaire, validated against Research Diagnostic Criteria diagnoses made by psychiatrists in a sample of 84 mothers [1]. The original paper reported that the scale identified the large majority of women with depressive symptoms, and it was subsequently adopted as the standard postnatal screening measure in maternity care settings around the world.

The Japanese-language version was translated and validated by Okano and colleagues in 1996, published in the Japanese Journal of Psychiatric Diagnosis [2]. In the Japanese validation sample, a cutoff of 8/9 yielded a sensitivity of 0.75 and a specificity of 0.93 [2]. This is the version in routine use across Japan's postnatal health visits and the municipal perinatal mental health screening that accompanies the boshi techo — the Maternal and Child Health Handbook that is issued to all expectant parents in Japan.

A point the tool's developers have consistently emphasized: the EPDS is not a diagnostic instrument. It is a screen — a net designed to identify people who need more thorough assessment. A high score does not mean a diagnosis of depression. That diagnosis requires evaluation by a psychiatrist, psychotherapist, or other qualified clinician. The EPDS tells you who should be seen. It does not tell you what they have.

The Threshold Is Not One Number

A common misconception is that the EPDS has a single cutoff. In practice, different thresholds serve different purposes.

A 2020 individual participant data meta-analysis by Levis and colleagues, published in the BMJ, pooled 36 studies with 9,066 participants and reported and at each cutoff for detecting major depression via semi-structured interview [3]:

In practice, the 9/10 cutoff is typically used for population-level screening where minimizing missed cases is the priority; the ≥13 threshold is more common in research and clinical evaluation settings where reducing false positives matters more [3]. In Japan, the Okano et al. 8/9 threshold is widely used in municipal perinatal mental health programs [2].

The key implication: different thresholds are designed for different purposes. Reading "9 points, so I'm fine" or "13 points, so I have postpartum depression" misapplies the tool. A threshold is an entry point into a process, not an exit from uncertainty.

Prevalence — What "1 in 7 to 10" Actually Represents

Postpartum depression is not rare.

O'Hara and Swain's 1996 meta-analysis in the International Review of Psychiatry — the landmark study in this area — estimated the average prevalence of non-psychotic postpartum depression at 13% [4]. The "1 in 7 or 8" framing that circulates widely traces substantially to this figure.

Japanese data land in nearly the same range. A 2020 meta-analysis by Tokumitsu and colleagues in Annals of General Psychiatry, covering 123 studies and 108,431 Japanese women, estimated point prevalence at one month postpartum at 14.3% [5]. Prevalence was reported at 14.0% in the second trimester and 16.3% in the third trimester, with a gradual decline as the postpartum period progressed [5]. Japan's numbers are close to the global average — neither notably lower nor notably higher.

Data on fathers are also now available in sufficient quantity to be clinically meaningful. A 2010 meta-analysis by Paulson and Bazemore in JAMA, covering 43 studies and 28,004 fathers, estimated prenatal and postnatal paternal depression prevalence at 10.4% (95% CI 8.5–12.7%) [6]. The same analysis found a moderate correlation (r=0.31) between maternal and paternal depression within the same household [6] — suggesting that postpartum depression is better understood as a family condition than as one person's individual problem.

These numbers have a purpose beyond epidemiology. They disrupt the "only me" narrative. For a condition experienced by roughly one in seven to ten parents, "I must be uniquely weak" is simply not accurate. The data say otherwise.

Below the Threshold, and Still Struggling

What about a score of 7 or 8 — below the standard cutoff, no referral triggered, but every day still feels heavy?

In psychiatric research, this experience is recognized as , or minor depression [7]. It refers to clusters of depressive symptoms that do not meet full DSM-5 criteria for major depressive disorder but still produce functional impairment and subjective distress [7]. Subthreshold depression is documented as a risk factor for progression to major depression, and is associated with reduced quality of life and measurable functional decline compared to symptom-free groups.

In the postpartum period specifically, an EPDS score below 9 does not exclude the following, all of which warrant conversation with a clinician:

The EPDS is designed to detect major depression. Postpartum mental health is not a binary between major depression and complete wellbeing [7]. Subthreshold presentations are clinically real, and they deserve the same access to conversation and care.

The operating principle here: the threshold for reaching out is lower than the EPDS cutoff. When the score came back low but the struggle persists, "I'll manage because the number was okay" is not the right inference. "The number was okay but I'm still having a hard time, so I'll talk to someone" is a lower-cost choice that preserves more options.

Practical Next Steps

Three considerations for the period ahead:

  1. Use the EPDS as a starting point, not a conclusion: Scores from municipal postnatal health visits or maternity care settings are inputs to a clinical conversation, not verdicts. Don't self-diagnose from the number alone. When in doubt, the conversation is the appropriate next step.

  2. Treat partners and co-parents as part of the same screening landscape: Paternal depression prevalence is approximately 10%, and it correlates moderately with maternal depression within the same household [6]. In some countries this understanding is shaping policy toward family-level screening. Until formal structures catch up, it is worth partners asking each other — and worth families watching for signs in both directions.

  3. Identify one contact point before you need it: Options in Japan include the Children and Families Center (Kodomo Katei Center, formerly the Integrated Support Center for Pregnant Women and Children) [8], the clinician or midwife at a postnatal health visit, the public health nurse at the local health center, postnatal care programs, and general practitioners or psychiatric outpatient clinics. Having one phone number or office in mind during a calm moment is meaningfully different from having to search for it during a difficult one.

Tracking daily mood and sleep in an app like Memori creates a time-series picture of your state that is genuinely useful when you do speak with a clinician. It allows you to say "here is the past two weeks" rather than having to reconstruct everything from memory. This applies regardless of whether the EPDS score was high or low.

Summary

The EPDS was developed by Cox and colleagues in 1987 [1] and validated in Japanese by Okano and colleagues in 1996 [2]. Its thresholds — 9/10 in community screening contexts, ≥11 for balanced sensitivity and specificity, ≥13 for high specificity — are designed for different purposes, and none of them equates to a diagnosis [3].

Postpartum depression affects approximately 13% of people globally and 14.3% of Japanese women at one month postpartum [4,5]. Paternal depression affects approximately 10% of fathers in the perinatal period [6]. These are not unusual events; they are statistically common ones.

When the score falls below the threshold but the difficulty continues, that difficulty is clinically recognized and worth discussing [7]. The EPDS threshold is where major depression screening begins — it is not the lower bound of care that matters.

Sometimes the most useful thing is to speak before the score ever gets taken.

References

  1. Cox JL, Holden JM, Sagovsky R. Detection of postnatal depression. Development of the 10-item Edinburgh Postnatal Depression Scale. Br J Psychiatry. 1987;150:782–786. doi:10.1192/bjp.150.6.782. PMID: 3651732.
  2. Okano T, Murata M, Masuji F, et al. Reliability and Validity of a Japanese Version of the EPDS [in Japanese]. Seishinika Shindangaku (Japanese Journal of Psychiatric Diagnosis). 1996;7(4):525–533.
  3. Levis B, Negeri Z, Sun Y, Benedetti A, Thombs BD; DEPRESsion Screening Data (DEPRESSD) EPDS Group. Accuracy of the Edinburgh Postnatal Depression Scale (EPDS) for screening to detect major depression among pregnant and postpartum women: systematic review and meta-analysis of individual participant data. BMJ. 2020;371:m4022. doi:10.1136/bmj.m4022. PMID: 33177069.
  4. O'Hara MW, Swain AM. Rates and risk of postpartum depression—A meta-analysis. Int Rev Psychiatry. 1996;8(1):37–54. doi:10.3109/09540269609037816.
  5. Tokumitsu K, Sugawara N, Maruo K, Suzuki T, Shimoda K, Yasui-Furukori N. Prevalence of perinatal depression among Japanese women: a meta-analysis. Ann Gen Psychiatry. 2020;19:41. doi:10.1186/s12991-020-00290-7. PMID: 32607122.
  6. Paulson JF, Bazemore SD. Prenatal and postpartum depression in fathers and its association with maternal depression: a meta-analysis. JAMA. 2010;303(19):1961–1969. doi:10.1001/jama.2010.605. PMID: 20483973.
  7. Cuijpers P, Smit F. Subthreshold depression as a risk indicator for major depressive disorder: a systematic review of prospective studies. Acta Psychiatr Scand. 2004;109(5):325–331. doi:10.1111/j.1600-0447.2004.00301.x. PMID: 15049768.
  8. Children and Families Agency, Cabinet Office, Japan. On the Kodomo Katei Center. FY2024. https://www.cfa.go.jp/

Related