Table 2

Summary of descriptive statistics for active inference parameters by group

Parameter	Controls		Individuals with ARMS		Patients with FEP		Group comparison^*			Controls v. patients with FEP		Controls v. individuals with ARMS		Individuals with ARMS v. patients with FEP

	n	Mean ± SD	n	Mean ± SD	n	Mean ± SD	F_t	p value	ξ^†	Ψ (95% CI)	p value	Ψ (95% CI)	p value	Ψ (95% CI)	p value
Optimism prior	31	0.50 ± 0.05	23	0.51 ± 0.05	26	0.52 ± 0.05	1.04	0.367	0.23
Pavlovian win prior	31	0.55 ± 0.07	23	0.55 ± 0.05	26	0.56 ± 0.07	0.24	0.797	0.11
Pavlovian loss prior	31	0.52 ± 0.05	23	0.50 ± 0.06	26	0.53 ± 0.05	1.37	0.270	0.26
Outcomes sensitivity	31	5.08 ± 0.10	23	5.06 ± 0.03	26	5.04 ± 0.06	1.36	0.278	0.25
Forgetting	31	0.41 ± 0.16	23	0.42 ± 0.21	26	0.54 ± 0.17	5.08	0.013	0.42	−0.14 (−0.26 to −0.02)	0.009	0.01 (−0.13 to 0.15)	0.836	−0.15 (−0.29 to −0.00)	0.016
Prior on policy precision	31	1.69 ± 0.65	23	1.56 ± 0.34	26	1.35 ± 0.64	2.88	0.077	0.38	0.33, (−0.11 to 0.68)	0.070	0.05 (−0.22 to 0.36)	0.673	0.28 (−0.15 to 0.55)	0.082
Free energy	31	−62.89 ± 23.04	23	−71.77 ± 14.97	24	−79.53 ± 22.34	2.97	0.089	0.40	19.44 (1.23 to 36.45)	0.011	9.29 (−6.57 to 24.79)	0.140	10.15 (−5.29 to 24.50)	0.136
Maximum likelihood	31	−60.94 ± 23.16	23	−69.73 ± 14.79	26	−78.58 ± 21.45	4.26	0.028	0.45	21.46 (4.04 to 36.88)	0.003	8.59 (−6.17 to 22.52)	0.154	12.87 (−0.81 to 24.86)	0.025

ARMS = at-risk for mental health, CI = confidence interval, FEP = first-episode psychosis, SD = standard deviation.
↵* Robust ANOVA analysis of group differences of modelled parameters based on trimmed means using the bootstrap method.
↵† Explanatory measure of effect size (ξ) values of 0.10, 0.30 and 0.50 correspond to small, medium and large effect sizes.