Newcomer 1998.

Methods	Allocation: unclear. Blindness: unclear. Duration: 4 days. Funded by NIMH Scientist Development Awards.
Participants	Diagnosis: schizophrenia. DMS III‐R and clinician interview. N = 19. Age: average ˜ 32 years (SD 8). Sex: 9 M, 10 F. Setting: inpatient. History: unclear. Excluded: history of DSM‐III‐R substance dependence or abuse within the past 6 months, current pregnancy, any current medical illness including trauma, fever or dehydration in the past month, neurological disorders (except possible tardive dyskinesia) including any history of significant head injury, defined as loss of consciousness for longer than 5 minutes and/or with neurological sequelae. Body weight < 80% of ideal body weight, treatment with narcotics in the past month, any treatment with corticosteroids or high‐dose oestrogens within past 6 months Country: USA.
Interventions	1. Dexamethasone: successive doses of 0.5, 1, 1 and 1 mg at 2300 h on days 0 to 3. N = 11. 2. Placebo: N = 8. Other concurrent treatments: Participants were studied during ongoing 'typical' antipsychotic treatment, including haloperidol and adjunctive anticholinergics. They were also studied during ongoing nicotine use.
Outcomes	Global state: leaving the study early. Cognitive function: paced serial addition task, vigilance task, Benton line orientation task. Adverse events: spontaneous reporting of adverse events. Unable to use: mental state. Total psychotic symptoms (BPRS not reported), negative psychotic symptoms (SANS not reported). Cognitive functioning: paragraph recall test (data not available).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No statement provided.
Allocation concealment (selection bias)	Unclear risk	No statement provided.
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "...after 4 days of double‐blind, placebo controlled treatment with DEX..." (pg 67).
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "double‐blind" ‐ probably undertaken.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "double‐blind" ‐ probably undertaken.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Analyses excluded participants with missing data (n = 3). However, Quote: "analyses were also run that included all subjects (n=19) by applying conservative adjustments for missing data (mean performance values for the other three test days as the washout (day 11) performance value)."
Selective reporting (reporting bias)	High risk	Only baseline BPRS and SANS scores reported.
Other bias	High risk	Participants in placebo group received on average lower dose of antipsychotic medication compared with intervention group.