Efficacy of hyperbaric oxygen therapy in the treatment of depression

Table 2 Demographic variables assessed across the selected trials

Ref.	Country	Protocol	Sample size (n)	Age range (years)	Male: Female ratio
Feng and Li[23], 2017	China	RCT	60	18-50	42:18
Guo et al[24], 2023	China	RCT	180	22-60	104:86
Harch et al[25], 2020	United States	RCT	62	18-65	28:34
Koźmin-Burzyńska et al[26], 2016	Poland	RCT	50	28-80	41:9
Mi et al[27], 2021	China	RCT	64	18-65	Unspecified
Zilberman-Itskovich et al[28], 2022	Israel	RCT	73	48.4 ± 10.6 (mean)	29:34

RCT: Randomized controlled trials.