Scientists have discovered which personality traits cause insomnia

Why do some people sleep like babies while others toss and turn until dawn, unable to fall asleep? Scientists from Brazil have found an unexpected explanation: it could be because of your personality. A new study shows that certain personality traits are directly linked to insomnia.

Details: Bárbara Araújo Conway et al, Personality traits and insomnia: direct and anxiety-mediated associations, Journal of Sleep Research (2025). DOI: 10.1111/jsr.70003

Two types in particular stood out: those who are open to new things sleep better, but those who are anxious and emotionally unstable are much more likely to suffer from insomnia.

The study was conducted at the Faculty of Medicine of the University of São Paulo and published in the authoritative Journal of Sleep Research.

🧠 What personality traits affect sleep?

The scientists focused on the popular "Big Five" psychological model, which includes:

• Neuroticism - a tendency toward anxiety and emotional instability;

• Openness - curiosity and a desire to learn new things;

• Benevolence - empathy and concern for others;

• Integrity - responsibility and perseverance;

• Extraversion - sociability and energy.

It turned out that insomniacs were more likely to score high on neuroticism, and vice versa - they lacked openness, benevolence and conscientiousness. Extraversion, by the way, had almost no effect on sleep.

📊 What did the numbers show?

The study involved 595 people between the ages of 18 and 59. They were divided into two groups: those diagnosed with insomnia and those without sleep complaints. Each participant took a 60-question questionnaire, which was used to determine their personality profile.

Here's what the analysis showed:

• Neuroticism - high in 61.7 per cent of insomniacs compared to 32 per cent in the control group;

• Low openness - in 40.7% vs. 23%;

• Low b enevolence - in 31.5% vs. 23.2%;

• Low conscientiousness - in 37.7% vs. 24.1%.

Most importantly: the effect of neuroticism on insomnia is entirely explained by anxiety. That is, the more anxious a person is, the higher the risk that he or she will sleep poorly. Depression showed no such link.

💡 Why it matters

The authors of the study say: knowing a person's psychological characteristics can help in accurate diagnosis and personalised treatment of insomnia. Cognitive-behavioural therapy is now considered the gold standard, but sleep specialists are in short supply.

Therefore, medics urge to take into account not only the "sleep problem", but also to analyse the patient's anxiety and personality traits. In some cases, this may be even more important than prescribed sleeping pills.