The very name ‘psychiatric epidemiology’ suggests the spread of mental illness among populations. But can a mental illness really spread, like a virus? Are some mental illnesses more prevelant within certain societies? Is it possible to predict whether a certain mental disorder is likely to develop in a particular individual or population? These are some of the questions Jonathan put to Tomáš Formánek, who is currently at Cambridge University in the UK doing his PhD research in exactly this field. And, as the theme of last year’s RSI competition was Slovakia’s castles, we repeat a story from 2019 in which three Japanese university students studying in Bratislava on an exchange programme talk about their impressions of Slovakia – including its beautiful castles.