BackgroundCommunity-based screening for mental health problems may increase service use through feedback to individuals about their severity of symptoms and provision of contacts for appropriate services.AimsThe effect of symptom feedback on service use was assessed. Secondary outcomes included symptom change and study attrition.MethodUsing online recruitment, 2773 participants completed a comprehensive survey including screening for depression (n=1366) or social anxiety (n=1407). Across these two versions, approximately half (n=1342) of the participants were then randomly allocated to receive tailored feedback. Participants were reassessed after 3 months (Australian New Zealand Clinical Trials Registry ANZCTR12614000324617).ResultsA negative effect of providing social anxiety feedback to individuals was observed, with significant reductions in professional service use. Greater attrition and lower intentions to seek help were also observed after feedback.ConclusionsOnline mental health screening with feedback is not effective for promoting professional service use. Alternative models of online screening require further investigation.