Brain-derived neurotrophic factor levels in first episode of psychosis: A systematic review

Table 1 Characteristics of the included studies

Ref.	Sample	Age (yr)	Matched for	Illness duration (yr)	Medication	BDNF measurement
Jockers-Scherübl et al[9]	157 FEP	31.8	Age, gender	Not reported	Drug naïve	Serum
	72 Ctl	32.3
Zakharyan et al[10]	25 FEP	25.3 ± 9.2	Age, gender	18.4 ± 7.2	Drug naïve	Plasma
	105 Ctl	37.3 ± 11.3
Murphy et al[11]	15 FEP	18.6 ± 3.3	Age, gender	Not reported	Quetiapine	Serum
	15 Ctl	18.5 ± 3.1
Sotiropoulou et al[12]	50 FEP	29.84 ± 8.20	Age, gender	Not reported	Drug naïve	Serum
	50 Ctl	31.36 ± 7.96
Ruiz de Azua et al[13]	47 FEP	24.3 ± 8.5	Age, gender, education level	Not reported	Drug naïve, Rsp, Olz	Plasma
	47 Ctl	24.0 ± 8.8
Yoshimura et al[14]	50 FEP	30.8 ± 5.3	Age, gender	Not reported	Apz	Plasma
	50 Ctl	32.3 ± 7.1
Rizos et al[5]	20 FEP	30.8 ± 10.5	Age, gender, education level, employment	Not reported	Drug naïve	Serum
	21 Ctl	34.0 ± 4.7
González-Pinto et al[15]	18 FEP	24.39 ± 6.53	Age, gender	Not reported	Drug naïve1	Plasma
	18 Ctl	25.19 ± 5.95
Rizos et al[16]	37 FEP	26.81 ± 9.22	Age, gender	Not reported	Drug naïve	Serum
	22 Ctl	26.59 ± 4.47
Jindal et al[17]	41 FEP	22.40 ± 5.47	Age, gender	Not reported	Drug naïve	Serum
	41 Ctl	22.31 ± 5.67
Goto et al[18]	18 FEP	29 ± 11	Age, gender	9.4 ± 6.8	Drug naïve, Rsp/Olz/Apz	Serum
	18 Ctl	30 ± 11
Pillai et al[19]	34 FEP	32.19 ± 8.74	Age, gender	Not reported	Drug naïve	Plasma
	36 Ctl	38.30 ± 1.26
Rizos et al[20]	31 FEP	26.81 ± 9.22	Age, gender, education level, employment	Not reported	Drug naïve	Serum
	22 Ctl	26.81 ± 9.22
Chen da et al[21]	88 FEP	29.2 ± 9.6	Age, gender, education level, smoking	23.4 ± 19.1	Drug naïve	Serum
	90 Ctl	29.8 ± 9.8
Rizos et al[22]	14 FEP	25.4 ± 5.8	Age, gender, education level, employment	Not reported	Drug naïve	Serum
	15 Ctl	26.6 ± 5.0
Buckley et al[23]	15 FEP	21.00 ± 8.83	Age, gender	25.2 ± 33.0	Drug naïve	Plasma
	14 Ctl	25.00 ± 5.72
Palomino et al[24]	48 FEP	23.7 ± 1.0	Age, gender	Not reported	Atypical, mood stabilizers	Plasma
	43 Ctl	25.5 ± 0.8
Pirildar et al[25]	22 FEP	27.81 ± 9.54	Age, gender	15.2 ± 13.0	Drug naïve1	Serum
	22 Ctl	25.7 ± 5.8

¹BDNF levels were also assessed after antipsychotic treatment (Olz, Rsp, Cloz) but not included in the review. Data are presented as mean ± SD. Apz: Aripiprazole; BDNF: Brain-derived neurotrophic factor; Cloz: Clozapine; Ctl: Controls; FEP: First episode psychosis; Olz: Olanzapine; Rsp: risperidone.

Table 2 Basal levels of brain-derived neurotrophic factor

Ref.	FEP (ng/mL)	Controls (ng/mL)	Results	Effect size d (CI)
Jockers-Scherübl et al[9]	13.1 ± 5.9	13.2 ± 0.2	No difference	0.10 (-0.18-0.38)
Zakharyan et al[10]	0.176 ± 0.014	0.24 ± 0.3	↓ in FEP	1.21 (0.75-1.67)
Murphy et al[11]	Missing data	Missing data	No difference	-
Sotiropoulou et al[12]	12620 ± 1860	14520 ± 2180	↓ in FEP	0.64 (0.23-1.04)
Ruiz de Azua et al[13]	6.09 ± 3.70	9.19 ± 4.21	↓ in FEP	0.66 (0.24-1.07)
Yoshimura et al[14]	0.7 ± 0.4	Missing data	↓ in FEP	0.43 (0.03-0.82)
Rizos et al[5]	9.76 ± 4.61	15.33 ± 6.34	↓ in FEP	0.99 (0.34-1.64)
González-Pinto et al[15]	4.09 ± 2.31	5.80 ± 2.66	↓ in FEP	-
Rizos et al[16]	18.87 ± 8.23	29.20 ± 7.73	↓ in FEP	0.72 (0.17-1.26)
Jindal et al[17]	0.09 ± 0.03	0.117 ± 0.04	↓ in FEP	0.54 (0.10-0.99)
Goto et al[18]	Missing data	Missing data	No difference	0.38 (-0.28-1.04)
Pillai et al[19]	Missing data	Missing data	↓ in FEP	0.53 (0.05-1.00)
Rizos et al[20]	Missing data	Missing data	↓ in FEP	-
Chen da et al[21]	9.0 ± 4.2	12.1 ± 2.2	↓ in FEP	0.92 (0.61-1.23)
Rizos et al[22]	23.90 ± 5.99	30.00 ± 8.43	↓ in FEP	0.83 (0.07-1.59)
Buckley et al[23]	0.017 ± 0.003	0.049 ± 0.007	↓ in FEP	1.37 (0.56-2.18)
Palomino et al[24]	4.19 ± 2.26	7.55 ± 4.31	↓ in FEP	0.56 (0.13-0.97)
Pirildar et al[25]	14.2 ± 8.1	26.8 ± 9.3	↓ in FEP	1.07 (0.93-1.7)

Data are presented as mean ± SD. FEP: First episode psychosis.