Table 1 Demographics and clinical characteristics of ketamine in depressed patients with and without pain

Age, mean ± SD

35.8 ± 11.6

34.8 ± 11.5

36.8 ± 11.8

− 0.699

0.487

Male gender, n (%)

29 (43.9%)

13 (39.4%)

16 (48.5%)

0.554

0.457

Education (years), mean ± SD

12.2 ± 3.3

13.2 ± 2.9

11.1 ± 3.4

2.692

0.009

Employed, n (%)

31 (47.0%)

18 (54.5%)

13 (39.4%)

1.521

0.218

Body mass index (kg/m²), mean ± SD

22.7 ± 3.5

22.0 ± 3.6

23.4 ± 3.4

− 1.578

0.020

Duration of illness (months), mean ± SD

86.8 ± 76.6

77.9 ± 67.9

95.6 ± 84.5

− 0.989

0.326

Psychiatric comorbidity (yes), n (%)

11 (16.7%)

8 (24.2%)

3 (9.1%)

2.686

0.185

Family history of psychiatric disorders (positive), n (%)

20 (30.3%)

10 (30.3%)

10 (30.3%)

0.000

1.000

Dose of antidepressant (mg/day), mean ± SD

40.0 ± 21.4

36.8 ± 21.4

43.4 ± 21.2

− 1.243

0.218

On antipsychotic, n (%)

39 (59.1%)

21 (63.6%)

18 (54.5%)

0.564

0.453

On mood stabilizers, n (%)

14 (21.2%)

8 (24.2%)

6 (18.2%)

0.363

0.547

On benzodiazepines, n (%)

27 (40.9%)

12 (46.4%)

15 (45.5%)

0.564

0.453

Baseline MADRS score, mean ± SD

31.6 ± 7.6

31.2 ± 8.8

32.1 ± 6.4

− 0.449

0.655

Response rate after six infusions, n (%)

40 (60.6%)

16 (48.5%)

24 (72.7%)

4.062

0.044

Remission rate after six infusions, n (%)

26 (39.4%)

9 (27.3%)

17 (51.5%)

4.062

0.044

Days to response, mean ± SD

10.3 ± 8.1

12.4 ± 8.6

8.2 ± 7.2

2.130

0.037

Days to remission, mean ± SD

13.9 ± 7.7

15.8 ± 7.5

12.0 ± 7.6

2.025

0.047

Baseline VAS score, mean ± SD

2.4 ± 2.8

–

4.8 ± 2.2

NA

NA

Baseline sensory index, mean ± SD

2.2 ± 3.5

–

4.5 ± 3.8

NA

NA

Baseline affective index, mean ± SD

2.2 ± 3.1

–

4.3 ± 3.1

NA

NA

Baseline PPI, mean ± SD

1.1 ± 1.4

–

2.3 ± 1.1

NA

NA