Table 2.
Means, SDs, and F and P values for ANOVA effects for group, time, and group × time (G × T) and T and P values for the main outcome variables
| Outcome variables | |||||||||||
| Main effects | |||||||||||
| Outcome variables | Group | Pre-treatment Mean (SD) | Post-treatment Mean (SD) | 6-month f/u Mean (SD) | 12-month f/u Mean (SD) | Group F P |
Time F P |
G × T F P |
T1 vs. T2 T P |
T1 vs. T3 T P |
T1 vs. T4 T P |
| FIQ – Physical impairment | CBT | 4.35 (2.12) | 3.64 (2.30) | 3.00 (2.43) | 3.42 (2.29) | 2.45 ns | 0.71 ns | 0.84 ns | |||
| OBT | 4.77 (2.24) | 4.50 (1.91) | 3.94 (2.06) | 2.63 (1.57) | 0.10 ns | 0.63 ns | 3.13 0.004 | ||||
| AP | 4.19 (2.08) | 4.03 (2.09) | 4.77 (2.60) | 5.20 (2.51) | 0.17 ns | -2.27 ns | -2.90 0.006 | ||||
| CBT vs. OBT (F, P) | 1.28 ns | 5.02 ns | 1.73 ns | 1.94 ns | 3.07 ns | 0.68 ns | 6.57 0.001 | ||||
| CBT vs. AP (F, P) | 0.01 ns | 1.28 ns | 4.79 ns | 6.36 0.010 | |||||||
| OBT vs. AP (F, P) | 1.06 ns | 0.76 ns | 1.35 ns | 16.38 <0.001 | |||||||
| Pain intensity | CBT | 4.15 (0.84) | 3.54 (1.03) | 3.73 (0.94) | 3.18 (1.42) | 3.45 0.002 | 3.14 0.003 | 4.32 0.001 | |||
| OBT | 4.22 (0.99) | 4.12 (1.12) | 3.77 (0.94) | 3.05 (1.40) | 0.56 ns | 3.29 0.002 | 4.64 <0.001 | ||||
| AP | 3.80 (0.99) | 3.79 (1.07) | 4.07 (1.07) | 4.14 (1.46) | 0.39 ns | -2.82 0.008 | -2.08 ns | ||||
| CBT vs. OBT (F, P) | 0.21 ns | 2.23 ns | 0.15 ns | 0.49 ns | 1.83 ns | 11.70 <0.001 | 11.95 <0.001 | ||||
| CBT vs. AP (F, P) | 2.72 ns | 1.04 ns | 2.94 ns | 8.77 0.004 | |||||||
| OBT vs. AP (F, P) | 2.74 ns | 1.69 ns | 1.82 ns | 11.79 0.001 | |||||||
| MPI – Affective distress | CBT | 3.22 (1.02) | 2.84 (1.10) | 2.57 (1.05) | 2.56 (1.24) | 2.02 ns | |||||
| OBT | 3.17 (1.44) | 3.31 (1.29) | 3.14 (1.23) | 2.92 (1.23) | -0.61 ns | ||||||
| AP | 3.54 (1.29) | 3.62 (1.34) | 3.99 (1.37) | 4.16 (1.44) | -0.90 ns | ||||||
| CBT vs. OBT (F, P) | 0.29 ns | 2.43 ns | 2.88 ns | 1.09 ns | 8.34 0.001 | 0.28 ns | 5.89 <0.001 | ||||
| CBT vs. AP (F, P) | 1.96 ns | 6.97 ns | 20.65 <0.001 | 27.83 <0.001 | |||||||
| OBT vs. AP (F, P) | 2.79 ns | 0.96 ns | 4.94 ns | 9.26 0.004 | |||||||
| Number of physician visits | CBT | 30.55 (16.20) | 25.27 (18.47) | 1.79 ns | |||||||
| OBT | 36.87 (15.15) | 16.35 (18.26) | 5.57 <0.001 | ||||||||
| AP | 34.13 (12.17) | 47.65 (20.01) | -5.56 <0.001 | ||||||||
| CBT vs. OBT (F, P) | 2.59 ns | 4.77 0.010 | 10.99 <0.001 | 5.59 0.020 | 33.52 <0.001 | ||||||
| CBT vs. AP (F, P) | 1.16 ns | 24.22 <0.001 | |||||||||
| OBT vs. AP (F, P) | 0.72 ns | 46.04 <0.001 | |||||||||
Comparisons refer to pre-treatment, post-treatment, and 6- and 12-month follow-ups in the CBT, OBT, and AP groups. ANOVA, analysis of variance; AP, attention-placebo; CBT, cognitive behavior therapy; FIQ, Fibromyalgia Impact Questionnaire; f/u, follow-up; MPI, Multidimensional Pain Inventory; ns, not significant; OBT, operant behaviour therapy; SD, standard deviation.