Heresco‐Levy 2013.

Study characteristics
Methods	Double‐blind randomised controlled trial
Participants	Diagnosis: DSM‐IV major depressive disorder; insufficient therapeutic response during the current episode, defined as a ≥ 20 score on the HRSD‐21 despite two or more adequate antidepressant medication trials N: 26 Age: M = 53.0 (SD = 10.2) Sex: 62% female Baseline depression severity: D‐cycloserine group HRSD = 25.1 (SD = 5.6); placebo group HRSD = 27.2 (SD = 4.9)
Interventions	6 weeks of treatment D‐cycloserine (N = 13) gradually titrated: 250 mg (one capsule)/d for 3 days ‐> 500 mg (two capsules)/d for 18 days ‐> 750 mg (three capsules)/day for 1 week ‐> and 1000 mg (four capsules)/d for the last 2 weeks Placebo (N = 13) in identical capsules to D‐cycloserine and according to same dose escalation schedule Concomitant treatment: yes, patients continued on existing psychotropic medications
Outcomes	HRSD Response rate (≥ 50% reduction in HRSD scores) Remission rate (HRSD score ≤ 7) HAMA CGI BDI Adverse events
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: ''randomly allocated using a block size of four''
Allocation concealment (selection bias)	Unclear risk	No details given on allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: ''Clinical and research staff, patients and their families were unaware of and could not determine the study drug assignment by appearance or otherwise''
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: ''double blind'' no further details given
Incomplete outcome data (attrition bias) All outcomes	Low risk	Study reports dropouts
Selective reporting (reporting bias)	Unclear risk	Protocol unavailable, but data reported matches methods
Other bias	Low risk	No other potential sources of bias identified