Table 1.

Characteristics of the analyzed papers.

Authors	Study Design	N. of Cases	Method of Suicide	PMI	Control	Samples	Molecule Targeted	Method of Analysis
Hayley (2015) [46]	Case-control depressed suicide individuals vs. non-suicide	19	10 hangings 8 overdoses 1 fall from height	<6 h	19	Hippocampus PFC (BA10)	BDNF protein	Western blot
Schneider (2015) [47]	Case-control suicide individuals vs. non-suicide	6	NP	<1 day	6	BA10	BDNF gene	Microarray
Ropret (2015) [48]	Case-control suicide individuals vs. non-suicide	486	NP	NP	289	Venous blood	BDNF gene	Genotyping with PCR
Youssef (2018) [49]	Case-control depressed and not depressed suicide individuals vs.-non suicide	37	NP	<1 day	53	BA9, BA24, CB, and RB	BDNF Val66Met polymorphism and BDNF protein	PCR Western blot
Mysztak (2020) [50]	Case-control suicide individuals vs. non-suicide	14	7 hangings 3 overdoses 2 falls from height 1 drowning 1 overwhelmed by train	NP	8	Hippocampus PFC	BDNF protein	Western blot
Gadad (2021) [51]	Case-control MD individuals vs. MD with AUD-SUD vs. AUD-SUD vs. non-psychiatric individuals	39	NP	<2 days	18	BA10 Plasma CSF	BDNF and GDNF protein	Multiplex-based Luminex assay
Ropret (2021) [52]	Case-control suicide individuals vs. non-suicide	22	Hanging	NP	20	Hippocampus BA9 Blood	BDNF DNA methylation and mRNA	NGS and PCR
Erbay (2021) [53]	Case-control depressed suicide individuals vs. non-suicide	61	Hanging	10 h	25	Hippocampus	BDNF, TrkB mRNA, and protein	PCR

PFC: prefrontal cortex; BA: Brodman area; NP: not present; SNPs: single nucleotide polymorphism; CB: caudal brainstem; RB: rostral brainstem; CSF: cerebrospinal fluid; PCR: polymerase chain reaction; MD: mood disorder; AUD: alcohol use disorder; SUD: substance use disorder; NGS: next-generation sequencing.