Table 2.

Mean (±SD) pain task ratings across drug conditions and participant types.

Variable	Placebo		Naloxone
Variable	Healthy control	LBP	Healthy control	LBP
FP-MPQ-S	10.5 ± 6.55	11.3 ± 5.77	10.5 ± 6.19	11.2 ± 5.52
FP-MPQ-A	1.1 ± 1.79	1.2 ± 1.34	1.0 ± 1.77	1.3 ± 1.45
FP-VAS intensity	46.6 ± 24.54	53.3 ± 22.63	45.7 ± 20.76	57.2 ± 21.68
FP-VAS unpleasantness	51.2 ± 24.92	57.6 ± 22.51	47.8 ± 20.01	61.5 ± 24.79
FP-intra-task NRS	45.1 ± 25.47	47.7 ± 19.91	46.0 ± 23.73	48.8 ± 19.92
ISC threshold (s)	26.5 ± 32.25	31.1 ± 43.25	37.6 ± 49.68	40.6 ± 47.85
ISC-MPQ-S	8.6 ± 6.33	10.7 ± 5.11	8.4 ± 5.95	9.6 ± 4.82
ISC-MPQ-A	1.6 ± 2.02	1.4 ± 1.19	1.4 ± 2.09	1.4 ± 1.69
ISC-VAS intensity	43.2 ± 26.33	50.4 ± 21.9	43.0 ± 25.47	46.4 ± 25.68
ISC-VAS unpleasantness	52.6 ± 25.36	54.5 ± 22.01	53.7 ± 24.89	49.0 ± 26.91
ISC-intra-task NRS	44.8 ± 28.47	43.3 ± 18.72	42.3 ± 27.44	42.0 ± 17.33

FP, finger pressure task; ISC, ischaemic task; LBP, chronic low back pain; MPQ, McGill Pain Questionnaire-Sensory (S) and Affective (A) subscales; NRS, numeric rating scale; SD, standard deviation; VAS, visual analogue scale.