Young people who like to stay up late are more likely to drink alcohol and smoke than those who prefer early nights because they’re more impulsive, a new study shows.
Brunel University London and the University of Surrey investigated how impulsivity, anxiety and substance use links to ‘night owl’ personalities who function better in the evening.
The study out in the journal Chronobiology International asked 18- to 25-year-olds about their body clocks, sleep quality, anxiety, impulsivity, how much they smoke and how much caffeine and booze they drank.
Young people are known for late nights and lie-ins and those who indulge more are known to run a higher risk of mental health issues and problem substance use.
“We found the tendency to be a night owl was associated with higher levels of anxiety, impulsivity and alcohol and cigarette use,” said Brunel psychologist Dr Ray Norbury.
“What we don’t know is if night owls are more likely to engage with these harmful behaviours because they are already out late and so may just have more opportunities to drink and smoke, or whether the addictive behaviours (such as the stimulant effects of smoking) drive them to be up late.
“Clearly, this has implications for both the mental and physical health of our student populations. It may be that simple interventions to improve sleep hygiene could reduce substance use and anxiety in these young and potentially vulnerable adults.”
The scientists tested the student’s impulsivity levels by asking how long they were willing to wait before receiving a hypothetical cash reward. Evening types were more impulsive, preferring small immediate rewards over delayed larger ones. These types were also more anxious and reported higher alcohol, caffeine and cigarette use compared with their peers who prefer early nights.
Lower sleep quality did not explain this, so to see what could, researchers used a statistical technique called mediation analysis. They found the link between being an evening type and greater alcohol, caffeine and cigarette use was higher levels of impulsivity.
Dr Simon Evans, Lecturer in Neuroscience at the University of Surrey, said: “The consequences of high levels of substance use can be detrimental to long term physical and mental health, and these findings suggest ways we could reduce risky substance use behaviours in young people.”
Hayley Jarvis, Media Relations
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