BMC Public Health 2006, 6:211 http://www.biomedcentral.com/1471-2458/6/211 overall affective tone of the content was also coded as pos- itive, neutral or negative. We have not conducted a quali- tative analysis of these data but report briefly on the categories that emerged and on the overall affective tone (positive versus neutral/negative) of responses. Statistical calculations were executed in SPSS 14.0. Ethical approval The study was approved by Austin Health's Ethics Com- mittee and all participants gave informed written consent. Results Population In total, 479 postnatal women responded to the survey – just over half of the 920 who were approached: 873 by post, 21 by phone and 26 by face-to-face interview, including 245 women who had received a DSM-IV diag- nosis of depression as a result of being screened and referred to our clinic. All had completed the EPDS with a Maternal & Child Health Nurse in Victoria prior to the acceptability survey:- the average length of time since postnatal screening with the EPDS was 58.3 weeks (95% CI 54.5–62.0). The mean EPDS score of all 920 women was 12.47 (95% CI 12.06–12.87). This reflects the delib- erately high representation of women scoring above the cut-off (601 of those surveyed) who had a mean EPDS of 16.29 (95% CI, 16.00–16.58) compared to a mean of 5.26 (95% CI, 4.92–5.59) for the 319 who scored below cut-off. The average age of respondents, at the time they were screened, was 30.02 years (95 % CI, 32.6–33.43) and the average age of infants was 16.87 weeks (95% CI, 15.34–18.41). The 21 women surveyed by telephone had a mean EPDS of 12.86 (CI 10.48–15.23) and those 26 interviewed face- to-face averaged 16.77 (CI 15.41–18.3). These latter 26 women had all been referred for formal psychological assessment because of concerns over their emotional health, including elevated EPDS scores. Response rate All 47 women surveyed by telephone and in face-to-face interviews responded to the questions. Of those 873 women surveyed via post, 41 had changed address (survey forms were returned marked "no longer at this address"). The overall postal response rate among the remaining women was 432/832 (52%) and among these 832 women the likelihood of responding to the survey was related to EPDS screening score such that women who had higher scores were less likely to respond. Thus, postal non-respondents had significantly higher EPDS screening scores than postal respondents (13.3 versus 11.6, p < 0.05). Although detectably significant in the statistical sense, the slope of the underlying relationship is small so that for every 1-point increase in EPDS score, the odds of non-response rise only by around 4% (Odds Ratio 1.05, CI 1.03–1.07). There was no difference in response rates between those diagnosed with depression and those not diagnosed (χ2 = 0.82, df = 1, p = 0.37). There was also a rel- atively small but statistically detectable effect of the time elapsed since screening, such that for every week since screening the chances of non-response rose by about 0.8% (OR 1.008, 95% CI 1.004–1.012) independent of EPDS score. Acceptability of the EPDS Comfort level of completing the EPDS To provide a central measure of clinical acceptability the survey asked "How comfortable were you completing that questionnaire? (the EPDS)". Of 467 respondents who answered this question, 88 (18.8%) rated their experience of completing the EPDS as less than 'Comfortable' includ- ing 20 women (4.3%) who responded that they were 'Not Comfortable' – the uppermost level of discomfort on the scale. The frequency distribution of responses on the 5- point Likert scale is shown in Figure 1. The distributions of responses to this question were no different for those women surveyed by post, by telephone or in face-to-face interview (χ2= 7.47, df = 8, p = 0.49). Next, multiple regression models were fitted, employing backward elim- ination of non-significant terms beginning with the max- imal model. There were no significant relationships between comfort level and infant or maternal age (p = 0.34 and 0.99 respectively). There was a significant, nega- tive effect of screening EPDS score such that women with higher scores tended to rate their experience of filling out the EPDS as less comfortable (slope -0.069, p < 0.001). However, this did not result in significantly different fre- quency distributions of comfort levels in women diag- nosed versus those not diagnosed with depression (χ2 = 180 Number of 160 Women 140 120 100 80 60 40 20 0 Not Comfortable Very Comfortable Comfortable Women's Comfort level with EPDS fFDoiirgstturlreibevue1tlioinnboefinrgesspcorenesensedonwaith5-tphoeinEtPLDikSert scale of com- Distribution of responses on a 5-point Likert scale of com- fort level in being screened with the EPDS. Page 4 of 8 (page number not for citation purposes)