Brain-derived neurotrophic factor, sex hormones and cognitive decline in male patients with schizophrenia receiving continuous antipsychotic therapy

Table 1 Demographic characteristics, clinical data, brain-derived neurotrophic factor, and sex hormones in chronic antipsychotic-treated male patients with schizophrenia and healthy controls (mean ± SD)

Variable	CATM patients (n = 120)	Healthy controls (n = 120)	F or χ2 (P value)
Age (yr)	51.0 ± 10.3	52.2 ± 6.4	27.4 (0.28)
Education (years)	9.2 ± 3.0	9.1 ± 2.8	0.8 (0.62)
Smokers (%)	60.8	65.9	0.6 (0.4)
BMI (kg/m2)	25.7 ± 3.4	24.0 ± 2.2	33.5 (< 0.001)
BDNF (ng/mL)	2.5 ± 1.6	9.7 ± 3.2	35.5 (0.00)
FSH (ng/mL)	8.6 ± 6.7	9.0 ± 6.6	0.1 (0.67)
LH (ng/mL)	6.7 ± 3.3	4.9 ± 2.6	1.6 (0.00)
E2 (ng/mL)	40.5 ± 17.1	56.2 ± 24.3	4.5 (0.00)
P (ng/mL)	0.8 ± 0.3	0.8 ± 0.4	0.2 (0.84)
T (ng/mL)	4.8 ± 1.8	4.0 ± 1.2	2.4 (0.01)
PRL (ng/mL)	25.4 ± 22.4	10.6 ± 5.5	24.1 (0.00)
Age of onset (yr)	22.9 ± 5.8
Duration of illness (yr)	28.0 ± 9.3
PANSS score
Positive symptoms	11.3 ± 4.9
Negative symptoms	20.1 ± 10.0
General psychopathology	31.2 ± 9.0
Total score	62.6 ± 20.2

BDNF: Brain-derived neurotrophic factor; CATM: Chronic antipsychotic-treated male; BMI: Body mass index; FSH: Follicle-stimulating hormone; LH: Luteinizing hormone; E2: Estradiol; P: Progesterone; T: Testosterone; PRL: Prolactin; PANSS: Positive and Negative Syndrome Scale.

Table 2 Comparison of cognitive scores between chronic antipsychotic-treated male schizophrenia patients and healthy controls

Cognitive index	CATM patients	Controls	F (P value)	MD (95%CI)
DCT	304.1 ± 215.0	130.8 ± 43.3	50.8 (< 0.001)	173.2 (124.0 to 222.4)
SVF	16.0 ± 7.8	27.6 ± 7.9	0.0 (< 0.001)	-11.6 (-8.7 to -14.5)
SS	11.6 ± 4.2	16.4 ± 4.2	0.1 (< 0.001)	-4.7 (-3.4 to -6.1)
TMT-A	101.3 ± 57.9	50.0 ± 21.7	26.5 (< 0.001)	51.3 (35.6 to 67.0)
BDT	17.1 ± 9.0	31.8 ± 8.8	0.2 (< 0.001)	-14.7 (-11.6 to -17.8)
PASAT correct	19.8 ± 10.5	34.0 ± 10.2	0.0 (< 0.001)	-14.1 (-9.5 to -18.7)
PASAT try	23.9 ± 11.0	36.9 ± 10.7	0.4 (<0.001)	13.0 (-8.2 to 17.8)

95%CI: 95% confidence interval; DCT: Digit Cancellation Test; SVF: Semantic Verbal Fluency; SS: Spatial Span Test; PASAT: Paced Auditory Serial Addition Test; TMT-A: Trail Making Task; BDT: Block Design Test.

Table 3 Correlations between sex hormones and brain-derived neurotrophic factor levels in all subjects¹

	BDNF
	r	P value2	P value3	P value4
FSH (ng/mL)	0.068	0.467	0.638	NS
LH (ng/mL)	-0.256	0.007	0.011	NS
E2 (ng/mL)	0.343	< 0.001	0.001	S.
P (ng/mL)	0.074	0.459	0.173	NS
T (ng/mL)	-0.215	0.032	0.055	NS
PRL (ng/mL)	-0.267	0.004	0.04	NS

¹Pearson product moment.

²Before adjusting for confounding factors.

³After adjusting for confounding factors (body mass index).

⁴Bonferroni correction was applied (a new = 0.05/5 = 0.01).

NS: Not significant; S.: Significant; FSH: Follicle-stimulating hormone; LH: Luteinizing hormone; E2: Estradiol; P: Progesterone; T: Testosterone; PRL: Prolactin.

Table 4 Correlations between brain-derived neurotrophic factor levels and cognitive function in all subjects¹

	BDNF
	r	P value2	P value3	P value4
DCT	-0.376	< 0.001	0.0019	NS
Category fluency	0.539	< 0.001	0.022	NS
SS	0.307	< 0.001	0.398	NS
TMT-A	-0.516	< 0.001	0.010	NS
Block design	0.557	< 0.001	0.015	NS
PASAT correct	0.442	< 0.001	0.404	NS
PASAT try	0.405	< 0.001	0.201	NS

¹Pearson product moment.

²Before adjusting for confounding factors.

³After adjusting for confounding factors (body mass index).

⁴Bonferroni correction was applied (a new = 0.05/7 = 0.007).

NS: Not significant; DCT: Digit Cancellation Test; SS: Spatial Span Test; PASAT: Paced Auditory Serial Addition Test; TMT-A: Trail Making Task.

Table 5 Relationships between prolactin levels and psychotic symptoms in patients¹

	Positive symptoms score				Negative symptoms score				General psychopathology score
	r	P value2	P value3	P value4	r	P value2	P value3	P value4	r	P value2	P value3	P value4
PRL	0.152	0.098	0.254	NS	0.196	0.032	0.011	S.	0.181	0.048	0.030	NS

¹Pearson product moment.

²Before adjusting for confounding factors.

³After adjusting for confounding factors (body mass index).

⁴Bonferroni correction was applied (a new = 0.05/3 = 0.017).

NS: Not significant; S.: Significant; DCT: Digit Cancellation Test; SS: Spatial Span Test; PASAT: Paced Auditory Serial Addition Test; TMT-A: Trail Making Task.