Association between emotional functioning and biological rhythm disruptions in patients with schizophrenia

Figures & data

Table 1. Sociodemographic, clinical characteristics and cognitive test scores of studied population.

	SZ (n:41)	HC (n:40)	Test Statistics	p
Age (mean ± SD)	40.44 ± 10.81	42.83 ± 11.51	t = −.96	.34
Gender (female %)	% 39 (16/41)	% 55 (22/40)	χ^2  = 2.08	.15
Marital status (married %)	% 14.6 (6/41)	% 65.0 (26/40)	χ^2  = 21.49	<.001 *
Education (years, mean ± SD)	7.34 ± 5.58	10.20 ± 4.86	t = −3.00	.004 *
Employment status (unemployment %)	% 82.9 (34/41)	% 35.0 (14/40)	χ^2  = 19.26	<.001 *
Smoking (yes %)	% 51.2 (21/45)	% 42.5 (17/40)	χ^2  = .62	.43
ToM (RMET Score)	15.42 ± 4.92	20.28 ± 4.45	F = 16.01^a	<.001 *
Executive Functions
WCST- perseverative errors	41.58 ± 20.60 (43.50)	35.19 ± 25.77 (32.35)	Z = −2.33	.03 *
WCST- categories	1.92 ± 1.44 (32.33)	3.70 ± 2.94(43.82)	Z = −2.22	.02 *
Stroop Time difference	27.01 ± 15.51 (50.35)	15.48 ± 8.59 (29.38)	Z = −4.06	<.001 *
Compound score^b	−0.34 ± 0.59	0.26 ± 0.85	F = 9.08^a	.004 *
Duration of illness (mean ± SD)	16.39 ± 8.01
Age of onset (mean ± SD)	24.24 ± 8.39
CPZe (mg)	752.68 ± 474.38
PANSS-Total (mean ± SD)	66.29 ± 14.30
PANSS- Positive (mean ± SD)	14.71 ± 5.21
PANSS- Negative (mean ± SD)	18.73 ± 6.38
PANSS-General (mean ± SD)	32.85 ± 7.16

SZ, Schizophrenia patients; HC, Healthy controls; ToM, Theory of Mind; RMET, Reading the Mind in the Eyes Test; WCST, Wisconsin Card Sorting Test; CPZe, Chlorpromazine equivalent dose; PANSS, Positive and Negative Syndrome Scale.

t: Student's t-test; χ²: chi- square test; Z: Mann- Whitney U test.

^aOne-way analysis of covariance (ANCOVA) adjusted for age and education level.

^bCalculated by averaging the Z-scores of Stroop-time difference, WCST-categories and WCST-perseverative errors.

*p < .05.

Figure 1. Comparison of BRIAN total and subscale scores between patients and healthy controls. BRIAN total score and sleep, activity and social rhythm subscale scores were significantly higher in patient group than controls (p < .001; p = .02; p < .001 and p < .001, respectively). There was no significant diffirence between study groups in terms of eating subscale score (p = .39). Student's t-test was used to compare Brain total score and sleep subscale score; Mann-Whitney U test was used to compare activity, social rhythm and eating subscale scores. BRIAN: Biological Rhythm Interview of Assessment in Neuropsychiatry.

Table 2. The correlation of BRIAN total scores with cognitive domains and clinical symptoms in patient group.

	Test Statistics	p
ToM (RMET Score)	ρ = −.38	. 02 *
Executive Functions^a	ρ = −.09	.60
PANSS-total	ρ = .60	< . 001 *
PANSS-positive	r = .48	. 002 *
PANSS-negative	r = .33	. 04 *
PANSS-general	ρ = 0.67	< . 001 *

BRIAN, Biological Rhythms Interview of Assessment in Neuropsychiatry; ToM, Theory of Mind; RMET, Reading the Mind in the Eyes Test; PANSS, Positive and Negative Syndrome Scale.

ρ = Pearson correlation coefficient, r = Spearman's rank correlation coefficient.

^aCalculated by averaging the Z-scores of Stroop-time difference, WCST-categories and WCST-perseverative errors.

*p < .05.

Table 3. Regression analysis on ToM scores in patient group.

	B	SE	β	t	p
Age	−.11	.07	−.24	−1.68	.10
Gender^a	3.53	1.41	.35	2.50	.02 *
PANSS-total score	−.002	.06	−.006	−.04	.97
BRIAN	−.179	.08	−.39	−2.27	. 03 *

ToM, Theory of Mind; PANSS, Positive and Negative Syndrome Scale; BRIAN, Biological Rhythms Interview of Assessment in Neuropsychiatry.

B = Unstandardized beta coefficient; SE = Standard error; β = Standardized beta coefficient.

^aGender: 1 = Male; 0 = Female

*p < .05.