In late 2016, US officials in Cuba’s capital began experiencing a mysterious and often debilitating set of symptoms that came to be known as Havana syndrome. As two new studies into the condition are published, Ian Sample speaks to the Guardian’s world affairs editor, Julian Borger, who has been following the story, and to the consultant neurologist Prof Jon Stone, about what could be behind the condition. Help support our independent journalism at theguardian.com/sciencepod