J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 000, Number 000, January 2026, pages 000-000

Assessment of Social Functioning in Patients With Schizophrenia and Their First-Degree Relatives

Figure 1. Area under the receiver operating characteristic curve for calculating the cutoff value of SFS for schizophrenia. AUC: area under the curve; SFS: Social Functioning Scale.

Figure 2. Proportion of subjects with SFS < 140 in each group. ***P < 0.0001 Cochran-Armitage test. There was a significant linear trend in the proportion of SFS < 140 among the three groups. SCZ: schizophrenia; FR: first-degree relatives; HC: healthy controls; SFS: Social Functioning Scale.

Figure 3. SFS subscales for each group. *P < 0.05, **P < 0.01, ***P < 0.001. HC: healthy controls; FR: first-degree relatives; SCZ: schizophrenia; SFS: Social Functioning Scale.

Figure 4. The correlation between SFS scores of SCZ patients and their unaffected parents. A total of 22 pairs comprising patients with SCZ and their unaffected parents were included. The Spearman rank correlation coefficient was 0.3963 (P = 0.0679). The gray shaded area represents the 95% confidence interval. SCZ: schizophrenia.

**Table 1.** Subjects Background
	Total (n = 256)	SCZ (n = 44)	FR (n = 26)	HC (n = 186)	P
SCZ: schizophrenia; FR: first-degree relatives; HC: healthy controls; JART: Japan Adult Reading Test, SFS: Social Functioning Scale.
Sex (male), n (%)	96 (37.5%)	17 (38.6%)	6 (23.1%)	73 (39.2%)	0.2761
Age (years), mean ± SD	48.0 ± 16.0	52.7 ± 13.7	68.3 ± 11.1	44.0 ± 14.6	< 0.0001
Educational history (years), mean ± SD	13.5 ± 2.2	12.3 ± 2.0	12.4 ± 1.8	13.9 ± 2.1	< 0.0001
JART50, mean ± SD	106.3 ± 9.2	98.3 ± 11.5	105.0 ± 10.3	108.3 ± 7.2	< 0.0001
SFS total score, mean ± SD	149.2 ± 36.2	90.9 ± 36.5	130.1 ± 24.6	165.7 ± 16.8	< 0.0001

Table 1. Subjects Background

Total (n = 256)

SCZ (n = 44)

FR (n = 26)

HC (n = 186)

SCZ: schizophrenia; FR: first-degree relatives; HC: healthy controls; JART: Japan Adult Reading Test, SFS: Social Functioning Scale.

Sex (male), n (%)

96 (37.5%)

17 (38.6%)

6 (23.1%)

73 (39.2%)

0.2761

Age (years), mean ± SD

48.0 ± 16.0

52.7 ± 13.7

68.3 ± 11.1

44.0 ± 14.6

< 0.0001

Educational history (years), mean ± SD

13.5 ± 2.2

12.3 ± 2.0

12.4 ± 1.8

13.9 ± 2.1

< 0.0001

JART50, mean ± SD

106.3 ± 9.2

98.3 ± 11.5

105.0 ± 10.3

108.3 ± 7.2

< 0.0001

SFS total score, mean ± SD

149.2 ± 36.2

90.9 ± 36.5

130.1 ± 24.6

165.7 ± 16.8

< 0.0001

**Table 2.** Effect of Group (SCZ, FR, HC) on SFS Total Score: ANCOVA
	Estimate	SE	t value	P
Model: P < 0.0001, R² = 0.700. ANCOVA: analysis of covariance; HC: healthy controls; FR: first-degree relatives; SCZ: schizophrenia; SE: standard error; JART: Japan Adult Reading Test.
Group (HC)	29.71	2.32	12.8	< 0.0001
Group (FR)	–1.21	3.25	–0.37	0.711
Group (SCZ)	–28.5	2.88	–9.9	< 0.0001
Age	–0.12	0.09	–1.25	0.2113
Educational history	1.95	0.66	2.97	0.0033
JART50	0.40	0.18	2.23	0.0269
Sex (male)	–3.38	1.34	–2.52	0.0123
Sex (female)	3.38	1.34	2.52	0.0123

Table 2. Effect of Group (SCZ, FR, HC) on SFS Total Score: ANCOVA

Estimate

t value

Model: P < 0.0001, R² = 0.700. ANCOVA: analysis of covariance; HC: healthy controls; FR: first-degree relatives; SCZ: schizophrenia; SE: standard error; JART: Japan Adult Reading Test.

Group (HC)

29.71

2.32

12.8

< 0.0001

Group (FR)

–1.21

3.25

–0.37

0.711

Group (SCZ)

–28.5

2.88

–9.9

< 0.0001

Age

–0.12

0.09

–1.25

0.2113

Educational history

1.95

0.66

2.97

0.0033

JART50

0.40

0.18

2.23

0.0269

Sex (male)

–3.38

1.34

–2.52

0.0123

Sex (female)

3.38

1.34

2.52

0.0123

**Table 3.** Difference in SFS Total Score Between Groups: Linear Contrast Test Based on ANCOVA
	Difference in SFS total score ± SE	P
ANCOVA: analysis of covariance; SCZ: schizophrenia; FR: first-degree relatives; HC: healthy controls.
Difference between SCZ and FR	–27.3 ± 5.7	0.0067
Difference between FR and HC	–30.9 ± 4.9	0.0004
Difference between SCZ and HC	–58.2 ± 4.1	< 0.0001

Table 3. Difference in SFS Total Score Between Groups: Linear Contrast Test Based on ANCOVA

Difference in SFS total score ± SE

ANCOVA: analysis of covariance; SCZ: schizophrenia; FR: first-degree relatives; HC: healthy controls.

Difference between SCZ and FR

–27.3 ± 5.7

0.0067

Difference between FR and HC

–30.9 ± 4.9

0.0004

Difference between SCZ and HC

–58.2 ± 4.1

< 0.0001

**Table 4.** Cutoff Value for SCZ in the SFS Total Score
	SCZ (n = 44)	Other than SCZ (n = 212)	Sensitivity	Specificity
SCZ: schizophrenia; Other than SCZ: first-degree relatives and healthy controls; SFS: Social Functioning Scale total score.
SFS < 140	42 (95.5%)	32 (15.1%)	0.954	0.849
SFS ≥ 140	2 (4.5%)	180 (84.9%)

Table 4. Cutoff Value for SCZ in the SFS Total Score

SCZ (n = 44)

Other than SCZ (n = 212)

Sensitivity

Specificity

SCZ: schizophrenia; Other than SCZ: first-degree relatives and healthy controls; SFS: Social Functioning Scale total score.

SFS < 140

42 (95.5%)

32 (15.1%)

0.954

0.849

SFS ≥ 140

2 (4.5%)

180 (84.9%)