Wilhelm 2008.

Methods	Design: Randomised, double‐blind, placebo controlled trial Study duration: 5 weeks Follow‐up: 1 month Country: USA
Participants	Sample size: 33 adult participants eligible and agreed to participate, 29 initiated treatment Recruitment: participants were recruited through flyers posted in the community and in area outpatient clinics Inclusion criteria ‐ diagnostic classification criteria: primary diagnosis of OCD, DSM‐IV Inclusion criteria ‐ rating scales: Not reported Included disorders: OCD and co‐morbid diagnoses Co‐morbidities: MDD (N = 3), social phobia (N = 3), specific phobia (N = 3), dysthymia (N = 2), GAD (N = 2), anxiety disorder not otherwise specified (N = 1), depressive disorder not otherwise specified (N = 1), and panic disorder with agoraphobia (N = 1) Gender: not reported Mean age: mean age of DCS group 40.0 years (SD 13.4); mean age of placebo group 38.2 years (SD 13.0) Ethnicity: Not reported Pharmacotherapy during the study: Naturalistic prescribing allowed; 14 participants were taking an anti‐depressant, 5 participants were taking a benzodiazepine, and 1 participant was taking an antipsychotic
Interventions	Intervention: Participants received 100 mg doses of DCS administered 1 hour prior to 10 twice weekly sessions or exposure‐based behavioural therapy (n = 14) Comparison: Participants received placebo pill administered 1 hour prior to 10 twice weekly sessions of exposure‐based behavioural therapy (n = 15) Therapists: Advanced trainees, under the supervision of licensed psychologists, administered the ERP
Outcomes	Withdrawals; anxiety: Y‐BOCS; co‐morbid depression: BDI‐II, adverse events
Notes	Funding from Industry: No. Supported by internal funding provided by Massachusetts General Hospital Medication supplied by industry: No Authors work for industry: Unclear Study ID: NCT00126282
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Study was randomised but not stated how random sequence generation was done. However, since allocation concealment was adequate we assume that randomisation method also was adequate
Allocation concealment (selection bias)	Low risk	'The research pharmacies at Massachusetts General Hospital and the Institute of Living prepared and dispensed the study medication (100 mg d‐cycloserine or placebo) and maintained the coded random assignment schedule for the double‐blind design.'
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants and personnel blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	'Assessors blinded to treatment condition.'
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Thirty‐three patients signed consent form of which three did not meet inclusion criteria, one refused the treatment because he reported that he was “not ready for change”, and six discontinued treatment before the mid‐treatment evaluation. Twenty‐two patients completed the treatment and were included in the statistical analysis. One patient dropped out after the mid‐treatment evaluation; his data were carried forward. Reasons for dropping out before mid‐treatment were not provided, and all randomised patients not included in analysis
Selective reporting (reporting bias)	Low risk	All outcomes pre‐specified in protocol were reported
Other bias	Unclear risk	More than 40% of patients (14/33 patients) were receiving concomitant anti‐depressants, which might have confounded the results

(ADIS‐IV) Anxiety Disorder Interview Schedule for Adults, (SPAI) Social Phobia and anxiety Inventory, (LSAS) Liebowitz Social Anxiety Scale, (BFNES) Brief Fear of Negative Evaluation Scale, (LIS) Life Interference Scale, (GAF) Global Assessment of Functioning Scale, (SCID) Structured Clinical Interview for DSM‐IV, (YBOC‐S) Yale‐Brown Obsessive Compulsive Scale, (SUDS) Subjective Units of Distress Scale, (CGI‐S) Clinican's Global impressions of Severity Scale, (PDSS) Panic Disorder Severity Scale, (CAPS) Clinician Administered Post Traumatic Stress Disorder Scale, (PCL) PTSD Checklist, (BDI‐II) Beck's Depression Inventory, (PSS‐SR) Posttraumatic Stress Symptom Scale—Self Report, (STAI) State and Trait Anxiety Inventory, (SL90) Symptom Checklist 90, (AAVQ) Acrophobia Questionnaire with Avoidance, (AAQ) Anxiety sub‐scales, (ATHI) Attitudes Toward Heights Inventory, (BAT) Behavioural Avoidance Test, (PAS) Panic and agoraphobia scale, (MI) Mobility Index, (BAI) Beck's Anxiety Inventory, (HAM‐D) Hamilton Depression Scale, (CGI), Clinical Global improvement scale, (OCI‐R) Obsessive‐Compulsive Inventory Revised, (ADIS‐IV‐P) Anxiety Disorders Interview Schedule for DSM‐IV: Parent Version, (CY‐BOCS) Children’s Yale–Brown Obsessive Compulsive Scale, (MASC) Multidimensional Anxiety Scale for Children