Table 1 Characteristics of included studies

Camilleri et al. [28]

US

Cohort

Healthy (n = 41);

IBS-C (n = 49);

IBS-D (n = 44);

IBS-M (n = 29)

Healthy:33.6 ± 1.6;

IBS-C:38.6 ± 1.5;

IBS-D:35.4 ± 1.6;

IBS-M:37.2 ± 2.2

Healthy:100;

IBS-C:100;

IBS-D:93.2;

IBS-M:100

Rome II

HADS

7

Cho et al. [27]

Korea

Case–control

Healthy (n = 91);

IBS-C (n = 30);

IBS-D (n = 63);

IBS-M (n = 31)

Healthy:45.8 ± 15.2;

IBS:43.3 ± 14.3

Healthy:46.2;

IBS:49.2

Rome II

HADS

7

Jamali et al. [25]

Iran

Cross sectional

IBS-C (n = 75);

IBS-D (n = 55);

IBS-M (n = 120)

IBS-C:32.90 ± 10.1;

IBS-D:29.12 ± 10.4;

IBS-M: 31.97 ± 13.5

IBS-C:62.1;

IBS-D:48.8;

IBS-M:50

Rome III

BDI

7

Jones et al. [24]

Australia

Case–control

Healthy (n = 76);

IBS-C (n = 60);

IBS-D (n = 57);

IBS-M (n = 51)

Healthy: 38.8 ± 12.4;

IBS-C: 38.8 ± 12.6;

IBS-D: 41.1 ± 13.6;

IBS-M: 37.5 ± 13.3

Healthy:79;

IBS-C:86;

IBS-D:65;

IBS-M:85

Rome III

HADS

7

Lee et al. [23]

China

Case–control

Healthy (n = 20);

IBS-C (n = 20);

IBS-D (n = 20)

Healthy:50.7 ± 17.4;

IBS-C: 48.9 ± 16.3;

IBS-D: 49.2 ± 15.6;

Healthy:30;

IBS-C:30;

IBS-D:30

NA

MMPI

6

Medeiros et al. [22]

Brazil

Case–control

Healthy (n = 8);

IBS-C (n = 7);

IBS-D (n = 6);

IBS-M (n = 8)

Healthy:32.3(24–44);

IBS:39.9(20–60)

Healthy:25.0;

IBS:76.2

Roma II

HADRS

7

Miller et al. [21]

UK

Cohort

IBS-C (n = 296);

IBS-D (n = 256);

IBS-M (n = 448)

IBS:51.6(17–91)

IBS:80

Rome II

HADS

7

Seminowicz et al. [20]

Canada

Case–control

Healthy (n = 48);

IBS-C (n = 15);

IBS-D (n = 17);

IBS-M (n = 19)

Healthy: 31.1 ± 12.3;

IBS-C: 35.0 ± 13.4;

IBS-D: 32.0 ± 5.46;

IBS-M: 31.2 ± 10.9

NA

Rome II

HADS

8

Sugaya et al. [19]

Japan

Cross sectional

Healthy (n = 1881);

IBS-C (n = 45);

IBS-D (n = 61)

Healthy:19.77 ± 1.73;

IBS:19.53 ± 1.87

Healthy: 52.2;

IBS:56.3

Rome II

HADS

7

Thijssen et al. [18]

Netherlands

Cohort

Healthy (n = 137);

IBS-C (n = 33);

IBS-D (n = 52);

IBS-M (n = 60);

IBS-U (n = 9)

Healthy: 44.2 ± 19.3;

IBS: 44.5 ± 16.3

Healthy: 61;

IBS: 70

Rome III

HADS

8

De-Rong et al. [26]

China

Case–control

Healthy (n = 20);

IBS-D (n = 42)

Healthy:28.9 (20–38);

IBS-D:29.4 (22–40)

Healthy: 40;

IBS-D: 35.7

Rome III

HADS

8

Mujagic et al. [34]

Netherlands

Case–control

Healthy (n = 94);

IBS-C (n = 21);

IBS-D (n = 34);

IBS-M (n = 30);

IBS-U (n = 6)

IBS:44.4 ± 1.6;

Healthy:45.0 ± 2.0

IBS: 63.7;

Healthy:58.5

Rome III

HADS

7

Ladep et al. [35]

Nigeria

Cross sectional

IBS-C (n = 59);

IBS-D (n = 58);

IBS-A (n = 15)

32.0 ± 9.4

56.8

Rome II

DSM-IV

7

Qin et al. [33]

China

Case–control

Healthy (n = 18);

IBS-D (n = 40)

IBS-D:44.50 ± 9.27;

Healthy:42.33 ± 12.81

IBS-D:25;

Healthy:27.8%

Rome IV

HADS

8

Bruno et al. [30]

Italy

Cohort

IBS-C (n = 34);

IBS-D (n = 37);

IBS-M (n = 40)

IBS-C:47.6 ± 10.1;

IBS-D:46.7 ± 11.7;

IBS-M:45.6 ± 13.9

56.76

Rome III

HRSD/HRSA

7

Ford et al. [29]

Canada

Cross sectional

IBS-C (n = 175);

IBS-D (n = 380);

IBS-M (n = 509)

IBS-C:43.0 ± 16.1;

IBS-D:41.8 ± 15.0;

IBS-M:38.2 ± 14.7

IBS-C:80.6;

IBS-D:69.5;

IBS-M:77.0

Rome III

HADS

8

Mearin et al. [31]

Spain

Cohort

IBS-C (n = 160);

IBS-D (n = 182);

IBS-A (n = 175)

NA

IBS-C:83.1;

IBS-D:66.3;

IBS-A:79.4

Rome II

EuroQoL-5D

7

Okami et al. [32]

Japan

Cross sectional

IBS-C (n = 260);

IBS-D (n = 116);

IBS-A (n = 252)

NA

IBS-C:20.4;

IBS-D:6.6;

IBS-A:14.5

Rome II

HADS

7