Table 2.

Results mixed regression analyses

	Parameter	Beta	Std. error	df	t	p	Effect size Cohen’s d
PSS-SR+	Intercept	33.87	2.45	12.19	13.83	< 0.001
	Treatment	− 1.06	1.51	24.21	− 0.70	0.491	0.64
	Post-treatment	− 2.72	2.18	14.43	− 1.25	0.231	0.93
	3-months follow-up	− 8.70	2.52	15.92	− 3.45	0.003	1.53
	Time within baseline	0.58	0.30	41.34	1.94	0.060
	Time within treatment	− 0.57	0.38	48.96	− 1.50	0.140
	Time within post-treatment	− 1.79	0.87	144.41	− 2.06	0.041
VAS++ Negative emotions	Intercept	71.73	6.45	9.98	11.12	< 0.001
	Treatment	1.91	2.89	34.72	0.66	0.512	1.03
	Post-treatment	− 4.04	4.20	33.75	− 0.96	0.343	1.08
	3-months follow-up	− 10.42	4.94	57.69	− 2.11	0.039	1.39
	Time within baseline	2.97	0.75	44.07	3.98	< 0.001
	Time within treatment	− 2.17	1.03	58.12	− 2.10	0.040
	Time within post-treatment	− 1.35	2.22	286.01	− 0.61	0.544
VAS++ Self-beliefa	Intercept	2.14	0.34		6.22	< 0.001
	Treatment	0.24	0.14		1.67	0.099	1.15
	Post-treatment	0.52	0.22		2.37	0.20	0.99
	3-months follow-up	0.93	0.25		2.86	0.005	2.35
	Time within baseline	− 0.19	0.04	89	− 5.04	< 0.001
	Time within treatment	0.13	0.05	104	2.50	0.014
	Time within post-treatment	− 0.02	0.20	293	− 0.09	0.932
VAS++ Body-beliefa	Intercept	1.37	0.37		3.74	0.004
	Treatment	0.08	0.12		0.65	0.518	1.16
	Post-treatment	0.46	0.18		2.51	0.014	1.41
	3-months follow-up	1.45	0.26		5.67	< 0.001	3.79
	Time within baseline	− 0.13	0.03	70	− 4.22	< 0.001
	Time within treatment	0.09	0.04	86	2.06	0.043
	Time within post-treatment	− 0.01	0.15	293	− 0.04	0.972
PTCI+	Intercept	179.42	5.82	13.37	30.81	< 0.001
	Treatment	6.57	4.35	42.08	1.51	0.138	1.80
	Post-treatment	− 8.13	6.15	15.98	− 1.32	0.205	2.98
	3-months follow-up	− 15.35	7.08	18.88	− 2.17	0.043	4.00
	Time within baseline	3.77	0.93	40.68	4.04	< 0.001
	Time within treatment	− 4.13	1.84	85.34	− 2.24	0.028
	Time within post-treatment	− 0.35	2.49	107.96	− 0.14	0.887
BMI+	Intercept	16.08	0.49	9.84	32.82	< 0.001
	Treatment	0.95	0.23	125.25	4.20	< 0.001	− 1.75
	Post-treatment	1.83	0.38	108.79	4.78	< 0.001	− 2.52
	3-months follow-up	2.34	0.42	104.87	5.52	< 0.001	− 3.80
	Time within baseline	0.14	0.05	127.90	3.03	< 0.001
	Time within treatment	0.24	0.08	122.70	3.05	0.003
	Time within post-treatment	− 0.03	0.09	118.76	− 0.32	0.752
EDE-Q+	Intercept	4.51	0.40	10.74	11.41	< 0.001
	Treatment	− 0.07	0.20	11.78	− 0.34	0.739	0.08
	Post-treatment	− 0.14	0.28	4.83	− 0.52	0.627	0.29
	3-months follow-up	− 0.75	0.31	6.35	− 2.42	0.050	1.45
	Time within baseline	− 0.03	0.05	17.81	− 0.71	0.486
	Time within treatment	− 0.03	0.09	72.52	− 0.32	0.752
	Time within post-treatment	− 0.12	0.12	118.82	− 0.97	0.333
DERS+	Intercept	117.41	5.32	10.94	22.08	< 0.001
	Treatment	0.27	2.56	33.71	0.11	0.917	0.77
	Post-treatment	− 1.86	3.60	9.33	− 0.52	0.617	0.97
	3-months follow-up	− 13.19	4.27	10.90	− 3.09	0.010	2.41
	Time within baseline	0.96	0.53	27.62	1.81	0.081
	Time within treatment	− 1.13	1.12	87.76	− 1.01	0.316
	Time within post-treatment	− 0.82	1.57	111.70	− 0.52	0.602

^aAnalyzed by mixed gamma regression with a log link, after inversing raw scores by 101-raw score (in mm.). This implies that beta’s are in transformed scale, and that positive time effects denote improvement

^+,++Time-within-Condition: 0 for measurements outside the condition, centred time (with a week as unit) for measurements within condition (⁺e.g., − 3, − 2, − 2, − 1, 0, 1, 2, 3 for a 6-week condition; ⁺⁺e.g., − 3, − 2.5, − 2, − 1.5, − 1, − 0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3 for 2 weekly measures in a 6 week condition)