Suicide attempt predictors among adolescents exhibiting non-suicidal self-injury: A six-week follow-up open study

Table 1 Demographic and clinical data, n (%)

	Low risk	High risk	χ2/t	P value
Age (years, mean ± SD)	14.83 ± 1.82	14.6 ± 1.516	0.564	0.575
Gender (men/women)	5/25	4/34	0.146	0.703
Smoking/drinking	9 (30.00)	17 (44.74)	1.542	0.214
Have physical illnesses	2 (6.67)	9 (23.68)	2.435	0.119
Only child	16 (53.33)	15 (39.47)	1.298	0.255
Urban household registration	16 (53.33)	27 (71.05)	2.264	0.132
Single parent family	9 (30.00)	13 (34.21)	0.136	0.712
Father with education above high school	16 (53.33)	21 (55.26)	0.025	0.874
Mother with education above high school	18 (60.00)	17 (44.74)	1.564	0.211
Family history of mental illness	3 (10.00)	4 (10.53)	0.005	1.000

Categorical variables (e.g., gender and smoking/drinking status) were analyzed using χ² tests, while continuous variables (e.g., age) were assessed via independent samples t-tests.

Table 2 Comparison of clinical scale scores between the two groups, mean ± SD

	Low risk	High risk	t	P value
HDRS	44.17 ± 10.58	52.16 ± 9.06	-3.355	0.001
HAMA	29.00 ± 9.91	36.24 ± 9.60	-3.042	0.003
RSES	20.53 ± 5.83	16.37 ± 4.39	3.362	0.001
ATQ	106.37 ± 28.62	128.79 ± 15.81	-4.106	0.000
SSRS	50.33 ± 14.47	36.76 ± 13.47	3.993	0.000
ISI	14.27 ± 5.42	19.55 ± 5.94	-3.786	0.000

HDRS: Hamilton Depression Rating Scale; HAMA: Hamilton Anxiety Rating Scale; RSES: Rosenberg Self-Esteem Scale; ATQ: Automatic Thoughts Questionnaire; SSRS: Schizophrenia Suicide Risk Scale; ISI: Insomnia Severity Index.

Table 3 Comparison of inflammatory cytokines between the two groups

Inflammatory cytokine	Low risk	High risk	Z	P value
TNF-α	3.46 (2.65, 4.09)	3.84 (3.10, 5.35)	-1.561	0.118
IL-6	1.91 (1.28, 3.03)	1.77 (1.52, 3.78)	-0.669	0.503
IL-10	0.94 (0.63, 1.14)	1.12 (0.95, 1.27)	-2.522	0.012
IL-1	2.68 (2.59, 3.40)	2.99 (2.59, 3.40)	-1.280	0.201
IFN-γ	11.25 (10.57, 13.06)	10.90 (10.90, 12.32)	-0.330	0.742
IL-4	3.32 (2.02, 3.32)	3.32 (2.02, 3.32)	-0.252	0.801
IL-17	3.46 (3.27, 3.90)	3.46 (2.69, 4.38)	-0.329	0.742
IL-2	6.18 (4.35, 7.54)	5.88 (5.03, 7.06)	-0.334	0.738
IFN-α	1.85 (1.70, 2.00)	2.00 (1.96, 2.00)	-2.033	0.042
IL-12	129.96 (110.96, 150.45)	145.24 (117.95, 150.45)	-0.847	0.397

Mann-Whitney U test (non-parametric) was used to compare inflammatory cytokine levels between the low- and high-risk groups. Data are presented as median, with Z and P values reported. TNF: Tumor necrosis factor; IL: Interleukin; IFN: Interferon.

Table 4 Factors affecting suicide risk

Risk factor	Regression coefficient	SE	Wald χ² value	P value	Exp(B)
TNF-α	0.38	0.23	2.81	0.094	1.464
IL-10	3.06	1.38	4.92	0.027	21.402
IFN-γ	-0.03	0.09	0.10	0.757	0.972
ISS	0.10	0.08	1.59	0.208	1.102
HDRS	0.05	0.05	0.75	0.386	1.046
HAMA	-0.05	0.06	0.61	0.435	0.954
RSES	-0.01	0.10	0.02	0.898	0.987
ATQ	0.04	0.03	1.55	0.213	1.037
SSRS	-0.04	0.03	1.55	0.214	0.959
Somatic disorders	-1.43	1.28	1.25	0.263	0.240
Regional factors	-1.44	0.86	2.81	0.094	0.236
Constant	-6.87	5.35	1.65	0.199	0.001

Binary logistic regression analysis was performed to assess the impact of risk factors on the outcome variable. TNF: Tumor necrosis factor; IL: Interleukin; IFN: Interferon; ISS: International Staging System; HDRS: Hamilton Depression Rating Scale; HAMA: Hamilton Anxiety Rating Scale; RSES: Rosenberg Self-Esteem Scales; ATQ: Automatic Thoughts Questionnaire; SSRS: Schizophrenia Suicide Risk Scale.

Table 5 Comparison of clinical scale scores before and after treatment

Clinical scale	Comparison group	Mean difference	SE	P value	95%CI
HDRS	Baseline vs 2-week time point	-23.00	2.73	< 0.001b	-28.41 to -17.59
	Baseline vs 6-week time point	-23.32	2.73	< 0.001b	-28.73 to -17.92
	2-week time point vs 6-week time point	0.32	2.73	0.906	-5.08 to 5.73
HAMA	Baseline vs 2-week time point	9.00	2.34	< 0.001b	4.37-13.63
	Baseline vs 6-week time point	7.74	2.34	0.001a	3.10-12.37
	2-week time point vs 6-week time point	-1.26	2.34	0.590	-5.90 to 3.37
ISS	Baseline vs 2-week time point	6.56	1.50	< 0.001b	3.60-9.53
	Baseline vs 6-week time point	6.45	1.50	< 0.001b	3.47-9.40
	2-week time point vs 6-week time point	-0.13	1.50	0.932	-3.09 to 2.83

^aP < 0.01.

^bP < 0.001.

Repeated measures ANOVA was used to evaluate differences in scores of clinical scales (Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, International Staging System) across different time points (baseline, 2-week time point, 6-week time point). Bonferroni correction was applied for multiple comparisons. Results are reported as mean differences, standard errors, P values, and 95% confidence intervals. HDRS: Hamilton Depression Rating Scale; HAMA: Hamilton Anxiety Rating Scale; ISS: International Staging System; CI: Confidence interval.

Table 6 Pre- and post-treatment cytokine levels in the whole sample

Inflammatory cytokine	Pre-treatment	Post-treatment	Z	P value
TNF-α	4.05 (3.10, 4.67)	2.98 (2.11, 3.53)	-4.72	< 0.001b
IL-6	3.43 (1.28, 3.58)	1.42 (1.11, 1.62)	-4.615	< 0.001b
IL-10	1.04 (0.87, 1.21)	0.85 (0.56, 1.04)	-4.082	< 0.001b
IL-1	4.00 (2.59, 3.40)	2.58 (2.36, 2.77)	-4.306	< 0.001b
IFN-γ	12.43 (10.90, 13.03)	25.41 (9.30, 12.17)	-2.561	0.010a
IL-4	3.13 (2.02, 3.32)	7.02 (4.80, 8.87)	-5.401	< 0.001b
IL-17	3.42 (2.69, 3.79)	3.34 (3.05, 4.05)	-0.657	0.511
IL-2	5.82 (4.39, 7.24)	5.44 (4.37, 6.76)	-1.570	0.116
IFN-α	1.95 (1.70, 2.00)	2.27 (2.00, 2.46)	-4.814	< 0.001b
IL-12	137.66 (129.96, 150.45)	127.03 (111.56, 132.41)	-2.219	0.026a

^aP < 0.05.

^bP < 0.001.

Wilcoxon signed-rank tests (non-parametric) were used to compare inflammatory cytokine levels before and after treatment. Data are presented as median, with Z and P values reported. TNF: Tumor necrosis factor; IL: Interleukin; IFN: Interferon.