Shutter Island may see Martin Scorsese detour from the mob genre to tackle a psychological thriller – but the director’s approach to moviemaking hasn’t changed a bit, says star Leonardo DiCaprio. “Scorsese depends on actors doing their homework before they show up on set,” DiCaprio reveals. “He’s a master filmmaker who knows how to navigate the human mind and portray the human condition, but he lets the actors really dictate what he puts up on the screen.”

Mind-control and supernatural hi-jinks feature in the adap of Dennis Lehane’s psychological thriller, set in the 1950s, with DiCaprio as a US marshall trapped on the titular mental asylum investigating the disappearance of a murderer. Even off-screen, detective-work was essential.

“Marty loves to discuss everything at great length,” says DiCaprio. “We’d discuss the scenes like forensic detectives. That’s one of the most interesting, challenging, scary and fun parts of making his movies because, by the time you’re on set, you’re really committed.”

For authenticity Scorsese brought in Dr James Gilligan, who actually ran a hospital for the criminally insane, as technical advisor to capture the horror of the conditions in the asylum. And it’s a surprise there wasn’t mutiny on set, as rain, mist and high-speed gusts of wind battered the hurricane-drenched set, fraying tempers and nerves. According to DiCaprio: “If there wasn’t a crane dropping water on you then it was guys with fire-hoses or a giant fan blowing air into your face...”

Shutter Island is out on DVD and Blu-ray on 2 August.