Table 3 Associations between scores on each EPDS item, and the latent classes (2-class solution) for the 797 women with PPD included in the latent class analysis, presented as probability (p) of achieving the stated score on a given item for each class*

1. I have been able to laugh and see the funny side of things

As much as I always could

Not quite so much now

Definitely not so much now

Not at all

Class 1

0.0808

0.5476

0.3435

0.0281

Class 2

0.0108

0.1241

0.6188

0.2463

2. I have looked forward with enjoyment to things

As much as I ever did

Rather less than I used to

Definitely less than I used to

Hardly at all

Class 1

0.1290

0.6384

0.2326

0.0000

Class 2

0.0096

0.2308

0.6190

0.1407

3. I have blamed myself unnecessarily when things went wrong

No, never

Not very often

Yes, some of the time

Yes, most of the time

Class 1

0.8162

0.1649

0.0090

0.0099

Class 2

0.5777

0.3042

0.0976

0.0205

4. I have been anxious or worried for no good reason

No, not at all

Hardly ever

Yes, sometimes

Yes, very often

Class 1

0.0000

0.0025

0.0804

0.9171

Class 2

0.0069

0.0883

0.2380

0.6668

5. I have felt scared or panicky for no very good reason

No, not at all

No, not much

Yes, sometimes

Yes, quite a lot

Class 1

0.6913

0.2530

0.0455

0.0101

Class 2

0.3963

0.3469

0.2332

0.0236

6. Things have been getting on top of me

No, I have been coping as well as ever

No, most of the time I have coped quite well

Yes, sometimes I haven’t been coping as well as usual

Yes, most of the time I haven’t been able to cope

Class 1

0.9693

0.0287

0.0000

0.002

Class 2

0.7822

0.1973

0.0206

0.000

7. I have been so unhappy that I have had difficulty sleeping

No, not at all

Not very often

Yes, sometimes

Yes, most of the time

Class 1

0.6478

0.2543

0.0924

0.0055

Class 2

0.2214

0.3446

0.3441

0.0900

8. I have felt sad or miserable

No, not at all

Not very often

Yes, quite often

Yes, most of the time

Class 1

0.8985

0.1015

0.0000

0.0000

Class 2

0.2841

0.5856

0.1132

0.0172

9. I have been so unhappy that I have been crying

No, never

Only occasionally

Yes, quite often

Yes, most of the time

Class 1

0.8102

0.1756

0.0122

0.0020

Class 2

0.2965

0.4915

0.1949

0.0171

10. The thought of harming myself has occurred to me

Never

Hardly ever

Sometimes

Yes, quite often

Class 1

0.1523

0.3830

0.2315

0.2332

Class 2

0.0104

0.0836

0.2572

0.6488