Table 1. Baseline Demographic and Clinical Characteristics by Treatment Group.
| Characteristic | No. (%) | |
|---|---|---|
| Probiotic group (n = 24) | Placebo group (n = 25) | |
| Age, median (IQR), y | 32.5 (24.3-39.0) | 27.0 (23.0-41.0) |
| Sex | ||
| Female | 18 (75) | 21 (84) |
| Male | 6 (25) | 4 (16) |
| Weight, mean (SD), kg | 72.1 (18.5) | 79.7 (22.1) |
| BMI, median (IQR)a | 23.3 (21.3-29.2) | 25.9 (23.9-31.9) |
| Race and ethnicityb | ||
| Asian (non-Chinese) | 7 (29) | 0 |
| Multiracial | 3 (12) | 3 (12) |
| White | 13 (54) | 20 (80) |
| Other race | 1 (4) | 2 (8) |
| Depression severity | ||
| HAMD-17 total score, mean (SD) | 16.5 (2.9) | 17.3 (3.2) |
| IDS-SR total score, mean (SD) | 37.5 (10.1) | 37.0 (6.3) |
| CGI-S, median (IQR) | 4.0 (3.0-4.0) | 4.0 (4.0-4.0) |
| Duration of episode, median (IQR), wk | 51.0 (22.5-103.3) | 55.0 (22.5-173.0) |
| Number of episodes, median (IQR) | 3.0 (1.0-3.0) | 3.0 (1.0-5.0) |
| Antidepressant treatment | ||
| Duration, median (IQR), wk | 59.0 (11.0-201.0) | 34.0 (11.0-97.0) |
| Class | ||
| SSRI | 21 (88) | 24 (96) |
| SNRI | 3 (13) | 0 |
| Other | 0 | 1 (4) |
| Anxiety comorbidity | ||
| None | 12 (50) | 9 (36) |
| Generalized anxiety disorder | 10 (42) | 11 (44) |
| Any other anxiety disorder | 8 (33) | 10 (40) |
| OCD | 0 | 1 (4) |
| HAMA total score, mean (SD) | 15.8 (4.7) | 16.1 (5.1) |
| GAD-7 total score, mean (SD) | 10.6 (4.0) | 11.0 (4.6) |
| Diet and gastrointestinal health | ||
| Vegetarian | 3 (13) | 4 (16) |
| GSRS total score, median (IQR) | 12.5 (7.3-20.5) | 11.0 (8.0-22.0) |
| FFQ dietary quality, median (IQR), g per wk | ||
| Fruit | 20.0 (11.2-56.8) | 56.8 (11.2-56.8) |
| Vegetables | 56.8 (28.8-81.2) | 68.0 (36.4-127.6) |
| Oily fish | 0 (0-10.6) | 0 (0-2.3) |
| Fat | 30.9 (19.7-46.6) | 34.8 (20.4-47.8) |
| NMES | 21.1 (10.6-35.0) | 21.6 (10.9-38.8) |
| Alcohol intake | ||
| Rarely/never drink | 11 (46) | 9 (36) |
| <14 Units per wk | 8 (33) | 13 (52) |
| 14-21 Units per wk | 4 (17) | 3 (12) |
| >21 Units per wk | 1 (4) | 0 |
Abbreviations: CGI-S, Clinical Global Impression Severity subscale; FFQ, Food Frequency Questionnaire, Short-Form; GAD-7, General Anxiety Disorder; GSRS, Gastrointestinal Symptom Rating Scale; HAMA, Hamilton Anxiety Rating Scale; HAMD-17, Hamilton Depression Rating Scale, 17-item; IDS-SR, Inventory of Depressive Symptomatology Self Report; NMES, non-milk extracted sugars; OCD, obsessive-compulsive disorder; SNRI, serotonin–norepinephrine reuptake inhibitors; SSRI, selective serotonin reuptake inhibitors.
Calculated as weight in kilograms divided by height in meters squared.
Race and ethnicity data were collected through self-report by choosing one of the following categories: Asian (non-Chinese; British or any other), Black (British or any other), Chinese, multiracial (any), White (British or any other), or other race (any). Due to low numbers, the Black, Chinese and other race categories were combined.