Table 1 Item content and factor loadings (λ) of the CSI items

1

I feel unrefreshed when I wake up in the morning

2

My muscles feel stiff and achy

3

I have anxiety attacks

4

I grind or clench my teeth

5

I have problems with diarrhoea and/or constipation

6

I need help in performing my daily activities

7

I am sensitive to bright lights

8

I get tired very easily when I am physically active

9

I feel pain all over my body

10

I have headaches

11

I feel discomfort in my bladder and/or burning when I urinate

12

I do not sleep well

13

I have difficulty concentrating

14

I have skin problems such as dryness, itchiness, or rashes

15

Stress makes my physical symptoms get worse

16

I feel sad or depressed

17

I have low energy

18

I have muscle tension in my neck and shoulders

19

I have pain in my jaw

20

Certain smells, such as perfumes, make me feel dizzy and nauseated

21

I have to urinate frequently

22

My legs feel uncomfortable and restless when I am trying to go to sleep at night

23

I have difficulty remembering things

24

I suffered trauma as a child

25

I have pain in my pelvic area