The 2018 Global Drug Survey looked at the recreational drug use of 130,000 people across 44 countries.
Scotland ranked first for cocaine consumed in a single session with 1.2 grams, followed by England at 0.7 grams. The global average is 0.5 grams.
Researchers, who quizzed 15,000 cocaine users, said cocaine can be delivered “more quickly than a pizza” in Glasgow.
The study published on Tuesday found 36.7 per cent of users in Glasgow reported delivery of the drug “within 30 minutes”.
Easy access and higher purity are likely to lead to “escalating use and harms”, researchers said.
On alcohol, Scotland had the highest proportion of respondents (4.2 per cent) who sought emergency medical care after a drinking session.
The report said: “This is double the level of English drinkers seeking medical treatment after drinking (2.1 per cent), highlighting how entrenched a problem drinking is north of the border.”
Professor Adam Winstock, consultant psychiatrist and addiction medicine specialist, and founder of the survey, said: “The 2018 Global Drug Survey highlights how much more work there is to do with alcohol messaging in the UK.
“It is clear that the link between alcohol consumption and increased cancer risk is a message that is still not reaching UK drinkers and where it does, many chose to react to the message with scepticism.
He said the regularity of people ending up in accident and emergency departments was “truly alarming”.
Professor Winstock added: “That both England and Scotland are in the top 5 global nations needing emergency treatment after alcohol consumption is truly concerning.
“This is another finding that shows how much more work is required to drive home the message of responsible drinking.”
Katy MacLeod of Scottish Drugs Forum said the true weight of a drug sold as a ‘gram’ can vary and seems to be lower in Scotland than elsewhere.
She said: “The low purity of cocaine supplied in Scotland suggests that bulking agents have been used to dilute the drug and so the same weight in Scotland will have less cocaine than in other countries.
“Using with alcohol may mean that people are using cocaine to allow them to keep drinking alcohol and so it is alcohol that is driving this behaviour.
“Mixing alcohol with other drugs adds to the potential for harm to users and others.”