Correction

Figures & data

Figure 1. CONSORT diagram showing the flow of participants through each stage of the study.

Table 4. Main group, time, and interaction effects (group × time) (n = 115).

Measure	Group effect	Partial η2	Time effect	Partial η2	Group*Time effect	Partial η2
SOP	F(1, 113) = 0.00, p = .99	.00	F(1.86, 209.63) = 18.83, p < .001	.14	F(1.86, 209.63) = 16.72, p < .001	.13
SPP	F(1, 113) = 1.39, p = .24	.01	F(1.68, 189.40) = 0.94, p = .38	.01	F(1.68, 189.40) = 7.91, p < .001***	.07
OOP	F(1, 113) = 5.59, p = .02*	.05	F(1.95, 220) = 2.47, p = .09	.02	F(1.95, 220) = 1.29, p = .28	.01
PCI	F(1, 113) = 12.25, p = .002**	.08	F(2, 226) = 2.07, p = .27	.01	F(2, 226) = 41.51, p < .001***	.25
Help seeking	F(1, 113) = 0.00, p = .99	.00	F(1.72, 195) = 2.97, p = .06	.03	F(1.72, 195) = 1.01, p = .36	.01
Anxiety	F(1, 113) = 4.71, p = .03*	.04	F(1.90, 213.95) = 3.66, p = .03*	.03	F(1.89, 213.95) = 17.68, p < 001***	.14
Anger	F(1, 113) = 0.80, p = .37	.01	F(1.66, 187.98) = 9.76, p < .001**	.08	F(1.66, 187.98) = 4.50, p = .02*	.04
Dejection	F(1, 113) = 0.63, p = .43	.01	F(1.72, 194) = 6.23, p = .004**	.05	F(1.72, 193.84) = 5.50, p = .007**	.05
Happiness	F(1, 113) = 3.45, p = .07	.03	F(1.87, 211) = 4.97, p = .009**	.04	F(1.87, 210.74) = 0.58, p = .55	.01
Excitement	F(1, 113) = 2.87, p = .09	.03	F(1.91, 215.62) = 2.05, p = .13	.02	F(1.91, 215.62) = 0.11, p = .89	.00

Note. SOP = self-oriented perfectionism; SPP = socially prescribed perfectionism; OOP = other-oriented perfectionism; PCI = perfectionistic cognitions; HELP = help-seeking attitudes.

*p < .05. **p < .01. ***p < .001, two-tailed. Huynh-Feldt correction to df used when sphericity p < .05.

Table 3. Analysis of simple effects on all measures between intervention and control group at each time point (n = 115).

	Time 1					Time 2					Time 3
Measure	Intervention M (SD)	Control M (SD)	M differrence	p values	Cohen’s d	Intervention M (SD)	Control M (SD)	M difference	p values	Cohen’s d	Intervention M (SD)	Control M (SD)	M difference	p values	Cohen’s d
SOP	5.60 (0.74)	5.17 (0.73)	0.42**	.003	0.59	4.91 (0.83)	5.13 (0.75)	–0.22	.138	0.29	4.98 (0.89)	5.18 (0.81)	–0.20	.208	0.20
SPP	4.05 (0.94)	3.94 (0.72)	0.11	.476	0.20	3.83 (0.81)	4.02 (0.73)	–0.19	.188	0.29	3.80 (0.77)	4.18 (0.74)	–0.38**	.009	0.51
OOP	4.10 (0.68)	4.31 (0.81)	–0.21	.133	0.29	4.08 (0.71)	4.37 (0.70)	–0.29*	.029	0.41	4.12 (0.69)	4.48 (0.67)	–0.36**	.005	0.55
PCI	2.12 (0.91)	1.92 (0.89)	0.20	.227	0.23	1.61 (0.86)	2.25 (0.86)	–0.64***	.000	0.75	1.59 (0.82)	2.47 (0.72)	–0.88***	.000	1.15
HELP	2.12 (0.60)	2.18 (0.56)	–0.06	.583	0.00	2.23 (0.56)	2.23 (0.56)	–0.05	.961	0.00	2.27 (0.56)	2.22 (0.59)	0.05	.623	0.00
ANX	1.97 (1.17)	1.72 (1.07)	0.25	.237	0.20	1.34 (1.05)	1.97 (1.13)	–0.63**	.003	0.59	1.24 (1.03)	1.99 (1.10)	–0.76**	.000	0.70
ANG	0.98 (1.15)	0.80 (0.90)	0.19	.336	0.20	0.42 (0.67)	0.70 (0.88)	–0.28	.056	0.35	0.42 (0.75)	0.68 (0.94)	–0.26	.107	0.29
DEJ	0.91 (1.16)	0.69 (0.89)	0.22	.255	0.20	0.39 (0.68)	0.66 (0.81)	–0.27	.054	0.35	0.43 (0.85)	0.70 (0.99)	–0.27	.116	0.20
HAP	1.63 (1.04)	1.94 (1.05)	–0.31	.114	0.29	1.73 (0.97)	2.13 (1.08)	–0.40*	.039	0.41	1.98 (1.04)	2.18 (1.11)	–0.20	.332	0.20
EXC	2.05 (1.04)	2.32 (1.07)	–0.27	.175	0.29	2.09 (1.09)	2.34 (0.98)	–0.24	.215	0.20	2.20 (1.14)	2.52 (0.98)	–0.33	.103	0.29

Note. SOP = self-oriented perfectionism; SPP = socially prescribed perfectionism; OOP = other-oriented perfectionism; PCI = perfectionistic cognitions; HELP = help-seeking attitudes; ANX = anxiety; ANG = anger; DEJ = dejection; HAP = happiness; EXC = excitement.

*p < .05. **p < .01. ***p < .001, two-tailed.