BACKGROUND Mental health literacy has been defined as the public's knowledge and the beliefs about mental disorders enhancing the ability to recognise specific disorders. AIMS Firstly, to determine whether the public recognises a person depicted in a vignette as mentally ill or as experiencing a crisis. Secondly, to reveal the factors influencing the correct recognition. METHODS Multiple logistic regression analysis of an opinion survey conducted in a representative population sample in Switzerland (n=844). RESULTS The depression vignette was correctly recognised by 39.8% whereas 60.2% of the respondents considered the person depicted as having a 'crisis.' The schizophrenia vignette was correctly identified by 73.6% of the interviewees. A positive attitude to psychopharmacology positively influenced the recognition of the two vignettes whereas a positive attitude to community psychiatry had the inverse effect. Moreover, for the depression vignette previous contact to mentally ill people had a positive influence on the recognition. For the schizophrenia vignette instead, rigidity and interest in mass media had a negative influence, respectively. CONCLUSIONS The low knowledge about mental disorders, particularly depression, confirms the importance and the need to increase mental health literacy. Furthermore, professionals must openly discuss illness models with their patients, especially emphasising the differences between illness and crisis.