Widespread spiking of drinks with date-rape drugs such as Rohypnol and GHB is an "urban legend" fuelled by young women unwilling to accept they have simply consumed too much alcohol, academics believe.
A study of more than 200 students revealed many wrongly blamed the effects of a "bad night out" on date-rape drugs, when they had just drunk excessively.
Many are in "active denial" that drinking large amounts of alcohol can leave them "incoherent and incapacitated", the Kent University researchers concluded.
Young women's fears about date-rape drugs are so ingrained that students mistakenly think it is a more important factor in sexual assault than being drunk, taking drugs or walking alone at night.
The study, published in the British Journal of Criminology, found three-quarters of students identified drink spiking as an important risk – more than alcohol or drugs.
More than half said they knew someone whose drink had been spiked.
But despite popular beliefs, police have found no evidence that rape victims are commonly drugged with such substances, the researchers said.
Dr Adam Burgess from the university's School of Social Policy, Sociology and Social Research, said: "Young women appear to be displacing their anxieties about the consequences of consuming what is in the bottle on to rumours of what could be put there by someone else.
"The reason why fear of drink-spiking has become widespread seems to be a mix of it being more convenient to guard against than the effects of alcohol itself and the fact that such stories are exotic – like a more adult version of 'stranger danger'."
Rituals to protect drinks from contamination, such as taking drinks to the lavatory in clubs and bars and buying only bottled drinks, have become commonplace, the academics noted.
Among young people, drink spiking stories have attractive features that could "help explain" their disproportionate loss of control after drinking alcohol, the study found.
Dr Burgess said: "Our findings suggest guarding against drink spiking has also become a way for women to negotiate how to watch out for each other in an environment where they might well lose control from alcohol consumption."
Co-researcher Dr Sarah Moore said: "We would be very interested in finding out whether the urban myth of spiking is also the result of parents feeling unable to discuss with their adult daughters how to manage drinking and sex and representing their anxieties about this through discussion of drink spiking risks."
Nick Ross, chair of the Jill Dando Institute of Crime Science, commented: "There is no evidence of widespread use of hypnotics in sexual assault, let alone Rohypnol, despite many attempts to prove the contrary.
"During thousands of blood and alcohol tests lots of judgement-impairing compounds were discovered, but they were mostly street drugs or prescription pharmaceuticals taken by the victims themselves, and above all alcohol was the common theme.
"As Dr Burgess observes, it is not scientific evidence which keeps the drug rape myth alive but the fact that it serves so many useful functions."
Dr Burgess and his team questioned more than 200 students at universities in London and south east England.
Earlier this year, Australian researchers found that nont one of 97 young men and women admitted to hospital over 19 months to two Perth hospital claiming to have had their drinks spiked, had in fact been drugged.