HONG KONG (AFP) - Global turmoil after events such as Brexit and the election of President Donald Trump may push readers away from dystopian crime fiction to novels with a more comforting message, bestselling author Ian Rankin says.

The Scottish writer has made millions penning dark tales of serial killers and gangsters but thinks the current bleak outlook for world affairs may be a catalyst for a shift in what readers look for in fiction.

"I think this may happen - a move away from serial killers and bleak dystopian crime fiction towards something with a more comforting message," Rankin says.

"Maybe good will be seen to triumph and ordinary people will overcome crises in psychological crime novels," he adds.

It has been 30 years since Rankin introduced his famous protagonist John Rebus in Knots & Crosses, where he is a detective sergeant investigating a serial killer who has been abducting young girls.

As the brooding Rebus probed case after case involving shootings, prostitution, junkies and hit-and-runs, his books surged in popularity.

But Rankin believes troubled times in the real world could lead consumers to search for more light relief in fiction, pointing to the success of British writer Alexander McCall Smith, whose traditional mysteries set in Zimbabwe became popular after the 9/11 attacks in America.

Rejecting gruesome crime in favour of exploring everyday problems, his hit No.1 Ladies Detective Agency series also delighted in the simple things in life such as drinking tea.

"People craved normality and stories of kind people helping each other," Rankin says of McCall Smith's success.

But he will not abandon his tales about the grim underbelly of Edinburgh for "kind and gentle" books. "I am too much of a cynic. Maybe my books will become wilder and more chaotic instead," he adds.

His 22nd Rebus novel will be published next year.