Assessment of nerve growth factor levels and clinical indicators for outcome prediction in first-episode schizophrenia

Table 1 Demographic data and clinical characteristics of the study subjects, n (%)

	FEP group (n = 78)	HC group (n = 75)	χ2/t	P value
Gender (male/female)	40/38	42/33	0.342	0.559
Age (years)	26.03 (6.45)	26.51 (6.30)	-0.470	0.636
Education (years)	12.01 (3.18)	12.51 (3.85)	-0.870	0.382
Body mass index	22.42 (6.05)	22.46 (5.49)	-0.043	0.966
Smokers (yes/no)	28/50	33/42	1.050	0.306
Age of onset (years)	24.29 (5.27)
Duration of illness (years)	1.82 (2.14)
Family history of mental disorders (yes/no)	18/60
PANSS at baseline
Positive subscale	24.24 (8.47)
Negative subscale	21.42 (8.03)
General subscale	33.42 (3.59)
Total	79.09 (5.04)
PANSS after treatment
Positive subscale	16.09 (5.61)
Negative subscale	13.27 (4.28)
General subscale	20.08 (6.72)
Total	49.44 (11.78)

FEP: Never-medicated first-episode psychosis; HC: Healthy control; PANSS: Positive and Negative Syndrome Scale.

Table 2 Logistic regression models of treatment response at 8-week follow-up

	B	SE	Wald	Sig	EXP (B)	95%CI for EXP (B)
						Lower	Upper
NGF0	0.018	0.005	14.024	< 0.001	1.018	1.008	1.027
NGF1	0.016	0.004	14.860	< 0.001	1.016	1.008	1.024
NGF1 - NGF0	0.085	0.025	11.662	0.001	1.088	1.037	1.143
PANSS ≥ 20% response at 2 weeks	1.990	0.791	6.331	0.012	7.312	1.552	34.446

Variance inflation factor values were all below 2.0, indicating no serious multicollinearity. CI: Confidence interval; NGF₀: Baseline nerve growth factor; NGF₁: Nerve growth factor at 2 weeks after onset of antipsychotics treatment; PANSS: Positive and Negative Syndrome Scale.

Table 3 Receiver operating characteristic curve of variable sensitivity vs specificity

Variable	AUC	95%CI	P value	Youden index	Sensitivity	Specificity	PPV	NPV
NGF0	0.830	0.728-0.906	< 0.001	0.647	89.66	75.00	91.2	71.4
NGF1	0.842	0.742-0.915	< 0.001	0.647	89.66	75.00	91.2	71.4
NGF1 - NGF0	0.800	0.694-0.882	< 0.001	0.557	70.69	85.00	93.2	50.0
Early improvement	0.674	0.559-0.776	0.021	0.348	44.83	90.00	92.9	36.0
Combined variables	0.925	0.843-0.972	< 0.001	0.716	96.55	75.00	92.8	88.2

AUC: Area under the curve; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; NGF₀: Baseline nerve growth factor; NGF₁: Nerve growth factor at 2 weeks after onset of antipsychotics treatment.