Teenagers and young adults across Europe drink and take drugs as part of deliberate sexual strategies. New findings reveal that a third of 16-35 year old males and a quarter of females surveyed are drinking alcohol to increase their chances of sex, while cocaine, ecstasy and cannabis are intentionally used to enhance sexual arousal or prolong sex.

The study was conducted by researchers in public health and social sciences from across Europe. More than 1300 people aged between 16 and 35 and who routinely socialise in nightlife settings completed anonymous questionnaires.

Virtually all of the survey participants had drunk alcohol with most having had their first drink when 14 or 15 years old. Three quarters of the respondents had tried or used cannabis, while around 30 percent had at least tried ecstasy or cocaine.

Overall, alcohol was most likely to be used to facilitate a sexual encounter, while cocaine and cannabis were more likely to be utilised to enhance sexual sensations and arousal.

Despite these perceived sexual "benefits", drunkenness and drug use were strongly associated with an increase in risk taking behaviour and feeling regretful about having sex while under the influence of alcohol or drugs. Thus, participants who had been drunk in the past four weeks were more likely to have had five or more partners, sex without a condom and to have regretted sex after drink or drugs in the past 12 months. Cannabis, cocaine or ecstasy use was linked to similar consequences.

"Trends in recent decades have resulted in recreational drug use and binge drinking becoming routine features of European nightlife," says lead author Mark Bellis, from Liverpool John Moores University. "Millions of young Europeans now take drugs and drink in ways which alter their sexual decisions and increase their chances of unsafe sex or sex that is later regretted. Yet despite the negative consequences, we found many are deliberately taking these substances to achieve quite specific sexual effects."

Individuals were significantly more likely to have had sex under 16 years if they had used alcohol, cannabis, cocaine or ecstasy before that age. Girls in particular were as much as four times as likely to have had sex before the age of 16 if they drank alcohol or used cannabis under 16.

"Sexual activity accompanied by substance use is not just incidental, but often sexually motivated," says co-author, consultant psychiatrist Amador Calafat. "Interventions addressing sexual health are often developed, managed and implemented independently from those addressing substance use, and vice versa. However, young people often see alcohol, drugs and sex all as part of the same social experience and addressing these issues requires an equally joined up approach. "