Table 2.

Statistical results related to non-linear features (U-test).

Scales	Sub-scales	Statistical results
		Features	p-value
PANAS	PANAS PA	↓ MSE IBI (long CI)	<0.05
DERS	DERS non-Accept	↓ MSE IBR (short CI)	<0.05
		↓ MSE IBR (longCI)	<0.05
		↓ MMSE HRV-IBI (shortCI)	<0.01
		↓ MMSE HRV-IBI (longCI)	<0.01
	DERS Impulse	↓ 2V	<0.05
	DERS Awareness	↓ MMSE HRV-IBR (longCI)	<0.03
		↓ MMSE HRV-IBR (shortCI)	<0.05
	DERS Strategies	↓ 2V%	<0.05
IRI	IRI EC	↑ CD	<0.01
		↓ SD1	<0.01
		↓ DFA1	<0.05
		↓ MMSE HRV-IBR (shortCI)	<0.03
		↓ MMSE HRV-IBR (longCI)	<0.03
		↑ 1V%	<0.05
BIS/BAS	BIS	↑ CD	<0.03
	BAS	↓ MMSE HRV-IBR (shortCI)	<0.03
		↓ 0V	<0.03
		↓ 0V%	<0.03
ZKPQ	ZKPQ_Activity	↑ ApEn	<0.01
		↑ SampEn	<0.01
		↑ RP Lmax	<0.05

MSE HRV, Multiscale Entropy on HRV series; MSE IBR, Multiscale Entropy on IBR series; MSE IBI, Multiscale Entropy on IBI series; MMSE HRV-IBR, Multivariate Multiscale Entropy on bivariate HRV and IBR series; MMSE HRV-IBI, Multivariate Multiscale Entropy on bivariate HRV and IBI series; CI, Complexity Index. ApEn, Approximate Entropy, SampEn; Sample Entropy, 0V, number of patterns with none variation in the amplitude; 0V%, 1V%, 2V%, percentage of the total patterns with zero, one or two variations in the amplitude; SD1, Standard Deviation of PoincarÃl' Plot related to the points that are perpendicular to the line-of-identity; DFA1, Detrended Fluctuation Analysis (first slope); RP Lmax, Recurrence Plot (longest diagonal line); CD, Correlation Dimension ↑ indicates that an increase of the test score is associated to an increase of the feature value. ↓ indicates that an increase of the test score is associated to a decrease of the feature value.