Sheerin 2014.

Methods	Design: Randomised double‐blind placebo controlled study Study duration: 10 weeks Follow‐up: 6 months Country: USA
Participants	Sample size: 16 adult participants were found eligible and agreed to participate. Recruitment: flyers were posted around a university campus with relevant information about the nature of the study, what types of participants were being recruited, who was conducting the study, who to contact for more information, and information needed to schedule an initial assessment. Inclusion criteria ‐ diagnostic classification criteria: participants who met criteria for a current DSM‐IV diagnosis of social anxiety disorder. Inclusion criteria ‐ rating scales: Anxiety Disorders Interview Schedule (ADIS), supported by results of the Liebowitz Social Anxiety Scale (LSAS), with a minimum score (minimum 55) required for designation of moderate social anxiety. Included disorders: social anxiety disorder. Co‐morbidities: exclusion criteria included current major depressive episode, obsessive‐compulsive disorder, panic disorder, and post‐traumatic stress disorder, as well as diagnosis of bipolar disorder or psychosis, assessed by the ADIS‐IV. Additionally, anyone with a drug allergy that included medications in the class with DCS was excluded for health reasons, as well as anyone who was pregnant (determined by pregnancy test given at the initial screening), breast feeding, as was anyone who had medical conditions contraindicated for the experimental drug (e.g., a heart condition or epilepsy). Also, individuals who reported currently drinking alcohol on a daily basis were excluded. Gender: 63% female Mean age: 19.81 (SD 1.91), range not reported. Ethnicity: 63% non‐Hispanic white. Pharmacotherapy during the study: Potential participants were excluded if they were currently taking anti‐anxiety or anti‐depressant medications, currently using illicit substances, reported currently drinking alcohol on a regular basis or were on a medication that could potentially interact with DCS.
Interventions	Intervention: participants received 10 weekly 60‐minute sessions of exposure‐based cognitive behavioral therapy. Following each session, if the therapist determined that evidence of some extinction learning occurred during the session, they received a 250 mg DCS pill. N = 7 Comparison: participants received 10 weekly 60‐minute sessions of exposure‐based cognitive behavioral therapy. Following each session, if the therapist determined that evidence of some extinction learning occurred during the session, they received a placebo pill. N = 9 Therapists: sessions were conducted by doctoral graduate student therapists with a minimum of one year of supervised clinical experience.
Outcomes	Withdrawals: anxiety: LSAS (imputed SDs for DCS group); co‐morbid anxiety: STAI (imputed SDs for DSC group); adverse events.
Notes	Funding from industry: unclear. Medication supplied by industry: no, DCS and placebo purchased from a local pharmacy. Any author work for industry: unclear (PhD dissertation). Study ID: not stated. A dissertation submitted to the Graduate College in partial fulfilment of the requirements for the degree of Doctor of Philosophy ‐ West Michigan University.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A random number generator was used to randomly assign participants to one of two conditions.
Allocation concealment (selection bias)	High risk	"All participants, research assistants, and therapists were blind to the condition; however, the psychiatrist and pharmacy staff retained a list of all participants and those who were receiving DCS and placebo." Risk of bias is considered high, since the psychiatrist, whom all potential participants met with individually for a medical screening, was not blind to the allocation. Further, it is not specified in what way the blinding was carried out.
Blinding of participants and personnel (performance bias) All outcomes	High risk	"All participants, research assistants, and therapists were blind to the condition; however, the psychiatrist and pharmacy staff retained a list of all participants and those who were receiving DCS and placebo." Risk of bias is considered high, since the psychiatrist, whom all potential participants met with individually for a medical screening, was not blind to the allocation. Further, it is not specified in what way the blinding was carried out.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"All participants, research assistants, and therapists were blind to the condition."
Incomplete outcome data (attrition bias) All outcomes	High risk	"Of the 24 randomized participants, 16 entered treatment, with 7 in the DCS group and 9 in the placebo group." "Except where noted, all analyses were conducted using the intent‐to‐treat sample (N = 16)." "Of participants who entered treatment, 7 completed and 9 dropped out prior to session completion." Although the data for all intention‐to‐treat patients is reported and the reasons for attrition were reported, the high dropout rate (8 out of 24 before treatment and 9 out of 16 prior to treatment completion) could well have introduced a bias in the results, especially given the small sample size. Furthermore, only two participants completed the pre‐planned 6 months follow‐up assessment.
Selective reporting (reporting bias)	Low risk	All outcomes were completed and presented, as proposed.
Other bias	Low risk	No sources of other bias were identified.