Depression, depressive symptoms and treatments in women who have recently given birth: UK cohort study

Objectives To investigate how depression is recognised in the year after child birth and treatment given in clinical practice. Design Cohort study based on UK primary care electronic health records. Setting Primary care. Participants Women who have given live birth between 2000 and 2013. Outcomes Prevalence of postnatal depression, depression diagnoses, depressive symptoms, antidepressant and non-pharmacological treatment within a year after birth. Results Of 206 517 women, 23 623 (11%) had a record of depressive diagnosis or symptoms in the year after delivery and more than one in eight women received antidepressant treatment. Recording and treatment peaked 6–8 weeks after delivery. Initiation of selective serotonin reuptake inhibitors (SSRI) treatment has become earlier in the more recent years. Thus, the initiation rate of SSRI treatment per 100 pregnancies (95% CI) at 8 weeks were 2.6 (2.5 to 2.8) in 2000–2004, increasing to 3.0 (2.9 to 3.1) in 2005–2009 and 3.8 (3.6 to 3.9) in 2010–2013. The overall rate of initiation of SSRI within the year after delivery, however, has not changed noticeably. A third of the women had at least one record suggestive of depression at any time prior to delivery and of these one in four received SSRI treatment in the year after delivery. Younger women were most likely to have records of depression and depressive symptoms. (Relative risk for postnatal depression: age 15–19: 1.92 (1.76 to 2.10), age 20–24: 1.49 (1.39 to 1.59) versus age 30–34). The risk of depression, postnatal depression and depressive symptoms increased with increasing social deprivation. Conclusions More than 1 in 10 women had electronic health records indicating depression diagnoses or depressive symptoms within a year after delivery and more than one in eight women received antidepressant treatment in this period. Women aged below 30 and from the most deprived areas were at highest risk of depression and most likely to receive antidepressant treatment.

1. I am not quite clear about how the authors (or the administrators of the READ database) defined deression/postpartum depression and symptoms of depression. Are the prevalences estimated for each of these categories comparable to the reported prevalences reported in the literature? Are the assessments provided by the GPs to those with "symptoms of depression" reliable? What signs and/or symptoms are included in the "symptoms of depression"? 2. How should we understand the difference between any sort of depression and use of SSRI? Although the authors stated the use of SSRI to be intended for those with anxiety disorder (pp. 9), can it be a sole account for the 45% (100% minus 55% SSRI prescribed with any form of depression: Fig 1b)?
3. How did the authors count the number of those with depression before approximately 42 days after childbirth? What sort of women sought for help before 42 days as opposed to general referral patterns described in pp. 5? This is of interest as those with an early onset and with a later onset may reveal different background.
4. The literature cited here appear to be outdated and/or insufficient in some parts. For instance, pp. 10, LL. -1 the metaanalyses were published 17 years ago; there are a number of studies that follow, which have reported the "L-shape". What are the bases for taking "lower doses may be prescribed for other reasons such as chronic pain"? (Also, what are the cutoff points for "lower doses"?) I was expecting the estimate on total data to be a weighted average of the estimates in the subgroups. Thank you for explaining this result.
The most interesting result is the difference observed according to the deprivation indicator. The authors should highlight it and discuss it in more detail.

R1:
The large number of the study participants, who seem to be representative of the whole UK population, is an outstanding strength of this study. The estimates are thus reliable, and may be generalised. Clinical significance of this study is also of value.
We thank you for your positive comments. 2. How should we understand the difference between any sort of depression and use of SSRI? Although the authors stated the use of SSRI to be intended for those with anxiety disorder (pp. 9), can it be a sole account for the 45% (100% minus 55% SSRI prescribed with any form of depression: Fig  1b)?
Thanks for raising this issue. As we state in the discussion we are aware that the indication for SSRI prescribing is broader than depression and some women in our study may have received SSRI treatment for other indications for example anxiety. Yet, there is often an overlap between depression and anxiety and we chose therefore to include initiation of all SSRI prescriptions in our study.
We also believe that some GPs may omit to record another diagnosis of depression after delivery if the women already had such record. We have now estimated how often this occurred among women who were prescribed SSRI after delivery, but without records suggestive of depression.
Thus, we found of the 6,270 women with a prescription of SSRI without a record suggestive of depression within a year after delivery. Of these women, 4,818 (77%) had a record suggestive of depression or treatment prior to delivery. We have now included this information in the manuscript.
3. How did the authors count the number of those with depression before approximately 42 days after childbirth? What sort of women sought for help before 42 days as opposed to general referral patterns described in pp. 5? This is of interest as those with an early onset and with a later onset may reveal different background.

Thanks for raising this question, we have now examined the relationship between early (before 42 days) and late recording of depression and treatment according to age, social deprivation, calendar year and prior records of depression. The main findings are that a prior record suggestive of depression or treatment and more recent calendar period is associated with earlier recording (before 42 days). We include a summary of these analyses in the result section and provide the results of the full analyses in appendix 2.
4. The literature cited here appear to be outdated and/or insufficient in some parts. For instance, pp. 10, LL. -1 the metaanalyses were published 17 years ago; there are a number of studies that follow, which have reported the "L-shape".
We have now updated the literature and for example we now include a reference to paper (Muraca GM, Joseph KS. The association between maternal age and depression. J Obstet Gynaecol Can JOGC J Obstet Gynecol Can JOGC. 2014 Sep;36(9):803-10.) that suggest the associations between age and postnatal depression is somewhat U shaped. However, a lot of the relevant literature is relatively old and there are a limited number of newer studies that deals with the questions.
What are the bases for taking "lower doses may be prescribed for other reasons such as chronic pain"? (Also, what are the cutoff points for "lower doses"?) In the UK, treatment such as amitriptyline hydrochloride is also indicated for neuropathic pain at a lower dose (10 mg per day) and it is also used (although not licensed) for migraine prophylaxis (10 mg per day). In contrast the recommended initial dose for treatment of depression is 75 mg per day.
(for further details please see https://www.medicinescomplete.com). Therefore, we only considered doses of 75 mg and above as treatment for depression.
5. I appreciate it if the authors could provide some more details about the Townsend scores. Is the measurement based on income, education, occupation, residence, or anything else?
We apologies for the omission of the details on the Townsend scores. We have now included following text in the paper "The Townsend scores is based on census data (2011) for car ownership, owner-occupation, overcrowding and unemployment in a patient's postcode."

R2:
Please leave your comments for the authors below The part of figure (1B) on the combination of diagnoses is not understandable.
We apologies that we have not been able to describe the figure in sufficient detail. We now provide an example to help the reader to understand how the figure should be read. "For example, the figure illustrates that 82% of those who had a diagnosis of depression also had a prescription of a SSRI. On the other hand, 31% of those who had a prescription of SSRI had a diagnosis of depression." I am not sure the figures are useful.

We feel the figure provides a lot of information about the interrelationship between the recording of depression and treatment and would like to keep the figure in the paper.
I don't understand why the adjusted RR related to Townsend deprivation index, estimated on all data (last rows table 1 or table 2 The most interesting result is the difference observed according to the deprivation indicator. The authors should highlight it and discuss it in more detail.