Scottish drug users have been asked to contribute to the world's biggest narcotics survey.

Almost 160,000 people worldwide have taken part in the Global Drug Survey (GDS) so far this year.

It aims to find out how people use drugs, how they get them and how technology is changing drug use.

Last year's survey revealed nearly a quarter of Scottish drug users illegally bought narcotics on the dark web.

Professor Adam Winstock, a consultant psychiatrist and addiction medicine specialist who founded GDS, said its mission is to make drug use safer.

It also aims to identify new drug trends before they become mainstream, he said.

"The world of drugs is changing from where we get our drugs to how they're delivered, as well as the range of drugs available to us and their purity," Prof Winstock said.

"There's so much we don't know. We want to make sure people who take drugs are informed and break the idea that people who use drugs are idiots who don't care about themselves.

"Drugs are risky but how you use them really counts and we hope the survey can shed light on these behaviours. Our interest is in reducing drug-related harm."

This year it asks narcotics users how they lost their "drug virginity", how and what they drink and which prescription and illegal drugs they take.

Prof Winstock said alcohol is likely to feature strongly in survey responses from many Scots.

An average of 22 people a week died from alcohol-related illnesses in Scotland in 2015, according to the latest available figures, about 54% more than in England and Wales.

The 2018 GDS survey asks participants their opinion of warning labels on alcoholic drinks.

"For many, the elephant in the room is alcohol, Prof Winstock said.

"Scotland has been the smartest part of the UK in bringing minimum pricing and the next step is warning labels."

You can participate in the GDS 2018 survey until midnight on January 7.