Table 1.
Results Including All Those Providing Data (n = 58 at Posttreatment, n = 54 at 3-Month Follow-Up)
| Group | Mean (SD) |
Between-Group ANCOVA: F |
Between-Group Effect Size: d |
|||||
|---|---|---|---|---|---|---|---|---|
| Pretreatment | Posttreatment | Follow-Up | Posttreatment | Follow-Up | Posttreatment | Follow-Up | ||
| Primary outcomes measures | ||||||||
| Disability | ACT | 12.23 (4.53) | 9.96 (4.85) | 10.82 (5.55) | 3.16 | 6.10∗ | .32 | .59 |
| TAU | 12.19 (4.84) | 12.58 (6.02) | 14.14 (5.19) | |||||
| Depression | ACT | 11.58 (5.81) | 9.53 (6.84) | 9.95 (7.01) | 5.60∗ | 4.45∗ | .46 | .58 |
| TAU | 12.44 (7.03) | 13.04 (8.31) | 14.08 (6.68) | |||||
| Physical functioning | ACT | 30.35 (22.16) | 31.13 (19.99) | 31.51 (23.28) | <1 | 1.60 | .17 | .39 |
| TAU | 29.18 (27.76) | 27.32 (24.44) | 22.61 (21.19) | |||||
| Pain | ACT | 6.51 (1.92) | 6.45 (1.92) | 6.54 (2.10) | 1.41 | <1 | .44 | .32 |
| TAU | 7.00 (1.64) | 7.27 (1.73) | 7.19 (2.03) | |||||
| Treatment process measures | ||||||||
| Pain acceptance | ACT | 54.87 (14.39) | 64.97 (15.13) | 71.11 (8.86) | 3.60 | 5.83∗ | .26 | .64 |
| TAU | 56.92 (16.14) | 54.92 (17.04) | 64.89 (11.72) | |||||
| Psychological acceptance | ACT | 23.83 (10.77) | 23.60 (11.16) | 23.19 (12.00) | <1 | <1 | .20 | .22 |
| TAU | 24.72 (9.81) | 25.77 (10.75) | 25.55 (9.55) | |||||
| Secondary outcomes | ||||||||
| Emotional functioning | ACT | 52.02 (25.43) | 65.55 (16.93) | 64.21 (21.84) | 3.70 | 1.08 | .68 | .20 |
| TAU | 50.15 (23.71) | 50.50 (24.56) | 49.71 (22.11) | |||||
| Percentage Improved | χ2 | |||||||
| Patient rating of change | ACT | 53.33 | 51.90 | 4.43∗ | 3.43 | |||
| TAU | 25.00 | 26.08 | ||||||
| Medication reduction | ACT | 10.3 | 15.38 | <1 | <1 | |||
| TAU | 4.2 | 18.18 | ||||||
Abbreviation: ANCOVA, analysis of covariance.
NOTE. Disability was measured with the Roland and Morris Disability Questionnaire, depression with the Patient Health Questionnaire–9, pain with a 0 to 10 scale of average pain in the past week, physical and emotional functioning with the SF-36, pain acceptance with the Chronic Pain Acceptance Questionnaire, psychological acceptance with the Acceptance and Action Questionnaire–II, rating of change with the 1 to 7 Patient Global Impression of Change scale, and medication reduction with a single self-report item asking whether medication was increased, decreased, or stayed the same. Because of missing data, the actual n in the ACT condition varies from 28 to 31 and in the control condition from 26 to 27, including both posttreatment and follow-up time points.
P < .05. d > .20, small; >.50, medium; >.80, large.