TABLE 1.

Summary of quality assessment details and judgment for risk of bias of each study.

Study	Sequence generation		Allocation concealment		Blinding of participants and personnel		Blinding of outcome assessment		Incomplete outcome data
	Judgment	Comments	Judgment	Comments	Judgment	Comments	Judgment	Comments	Judgment	Comments
Dickerson et al., 2014	Unsure	No mention of sequence generation.	Unsure	No mention of allocation concealment for placebo vs. treatment groups.	Low	Study was double-blind, but there was no mention of how this was maintained.	Low	Study was double-blind, but there was no mention of how this was maintained.	Low	Subjects that were excluded were documented with reasoning.
Kazemi et al., 2019	Low	Patients were randomly assigned to experimental groups (1:1:1) in blocks of 6.	Low	Participants, clinicians, and raters remained blind to the allocated group of each participant.	Low	Participants, clinicians, and raters remained blind to the allocated group of each participant.	Low	Participants, clinicians, and raters remained blind to the allocated group of each participant.	Low	Subjects that were excluded were documented with reasoning.
Ghorbani et al., 2018	Unsure	No mention of treatment group sequencing.	Low	Double-blind study with 1:1 ratio for treatment vs. placebo randomization.	Low	Double-blind study. Throughout the study, the psychiatrist, the rater (study researchers), and the patients were all blind to allocation.	Low	The raters (study researchers) were blind to allocation.	Low	Subjects that were excluded were documented with reasoning.
Eskandarzadeh et al., 2021	Low	Patients were randomly assigned using a random numbers table to either treatment or placebo groups.	Low	Patients were randomly assigned using a random numbers table to either treatment or placebo groups.	Low	The study is double-blind, but there was no mention as to how that was maintained.	Low	The study is double-blind, but there was no mention as to if raters were blinded.	Low	Subjects who were excluded were documented with reasoning.
Arifdjanova et al., 2021	Low	Participants were randomized to either experimental or control group, but no mention as to how.	High	No concealment of treatment group.	High	No mention of blinding of staff.	High	No mention of blinding of raters.	Low	Some subjects were not included at the beginning, but criteria for which they were not included was not disclosed.
Miyaoka et al., 2018	Unsure	No mention of allocation sequence.	Unsure	No mention of allocation concealment.	High	No mention of blinding.	High	No mention of blinding.	Low	All data was reported and subjects that were excluded were documented with reasoning.
Rudzki et al., 2019	Low	Patients were randomly assigned to placebo or probiotic group using computer generated randomization list.	Low	The study was blinded at group allocator, participant, and assessor levels.	Low	The study was blinded at group allocator, participant, and assessor levels.	Low	The study was blinded at group allocator, participants, and assessor levels.	Low	Subjects that were excluded were documented with reasoning.
Yang et al., 2021	Unsure	No mention of how the participants were randomized.	High	The blind method was not used in this study, and the researchers were fully aware of the medication.	High	Researchers were fully unblinded and aware of the medication. No mention of unblinding to participants.	High	The blind method was not used in this study, and the researchers were fully aware of the medication.	Low	Subjects that were excluded were documented with reasoning.