Methods	Allocation: randomised, no further details. Blinding: double blind. Setting: Vienna, Austria. Inclusion criteria: not stated. Exclusion criteria: not stated. Follow up: 12 weeks.
Participants	Diagnosis: Adolescents at risk of 1st episode psychosis (Yung criteria). N=81*. Age: range 3-24 years; mean age 16.4. Sex: no details. History: no details.
Interventions	1. Omega-3 fatty acids: dose eicosapentaenoic acid 0.84 g/day; docosahexaenoic acid 0.7 g/day. N=38. 2. Placebo. N=38.
Outcomes	Transition to psychosis**. Unable to use - Leaving the study early Mental state: BPRS, PANSS (no usable data) Global state: GAF (no usable data). Adverse effects: UKU.
Notes	*5 participants not accounted for. **Operationally defined, based on Yung et al’s criteria, using cut-off points on PANSS subscales, (4 or more on hallucinations, 4 or more on delusions, and 5 or more on conceptual disorganization), and the frequency of symptoms (at least several times a week) and their duration (more than one week)
Risk of bias
Bias	Authors’ judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Randomised, no further details.
Allocation concealment?	Unclear risk	No described.
Blinding? All outcomes	Unclear risk	Double blind, untested.
Incomplete outcome data addressed? All outcomes	High risk	Study attrition not described.
Free of selective reporting?	Unclear risk	No details.
Free of other bias?	Unclear risk	No details.