Lapidus 2014.

Study characteristics
Methods	Double‐blind randomised controlled cross‐over trial
Participants	Diagnosis: DSM‐IV major depressive disorder; IDS‐C score ≥ 30 N: 20 Age: M = 48.0 (SD = 12.8) Sex: 50% female Baseline depression severity: IDS‐C = 42.7 (SD = 8.5)
Interventions	1 single intranasal infusion Ketamine (N = 10) 50 mg Placebo (N = 10) Study drug or placebo provided in identical syringes containing clear solutions of either 100 mg/mL ketamine in.9% saline or saline alone. 5 intranasal applications of solution separated by 5 minutes Concomitant treatment: Yes, patients continued on existing psychotropic medications
Outcomes	MADRS Response rate (≥ 50% reduction in MADRS scores) QIDS‐SR HAMA BPRS CADSS YMRS SAFTEE Adverse events
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: ''The order of treatment periods was randomly assigned by the research pharmacy using permuted blocks of size four''
Allocation concealment (selection bias)	Low risk	Quote: ''The order of treatment periods was randomly assigned by the research pharmacy using permuted blocks of size four''
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: ''All study investigators, anesthesiologists, and raters were blind to treatment assignment. Study drug or placebo was provided in identical syringes, containing clear solutions of either 100 mg/mL ketamine in.9% saline or saline alone''
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: ''Raters were blind to treatment assignment''
Incomplete outcome data (attrition bias) All outcomes	Low risk	Study reports dropouts
Selective reporting (reporting bias)	Unclear risk	Protocol unavailable. Data reported matches methods
Other bias	Low risk	No other potential sources of bias identified