MACHANG: The emergence of synthetic drugs that can drastically alter users' behaviour, making them appear like "zombies", is a growing concern, Home Minister Datuk Seri Saifuddin Nasution Ismail said.

He said there had been cases of people killing their spouses, parents and friends, with drug use showing a clear correlation with such violent incidents.

"If we look at these cases, they are closely linked to drug consumption," he told reporters.

Saifuddin said drug use patterns varied by region, with synthetic drugs more prevalent on the east coast, while drug abuse on the west coast involved a mixture of substances.