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At some point in our lives we’ve encountered someone – may it be in our own lives or in the TV or media – that enrages us so much that we wonder “how does that person sleep at night?!” Yet do our personalities affect our sleep? Will a particularly callous person find it difficult to sleep at night?

Well new research has found that our emotional and behavioural problems may indeed be intrinsically linked to how well we sleep at night. In fact, some personality types might find it easier to sleep at night than others as well as certain mental illnesses affecting the quality of sleep a night.

Does Your Personality Affect Your Sleep?For mental illnesses, the following has been found:

  • Schizophrenia – people will take far longer to fall asleep and will spend less time than most sleeping in their bed.
  • PTSD Sufferers – these people are often plagued by nightmares from their trauma and will find it hard to sleep and develop insomnia.
  • Depression – people will suffer from fragmented sleep and may find it hard to get to sleep or get back to sleep after waking in the night.

It’s also been thought that a poor sleep may, in fact, lead to some mental illnesses such as depression and ADHD. ADHD itself has a big association between not getting enough sleep and disruptive behavioural traits such as rule-breaking and aggression.

But these are all illnesses, what about those of us that we would just describe as having a ‘bad personality’? Here disruptive behaviour is linked to callous and unemotional traits rather than a disorder like ADHD that can be treated with medication. Here people lack guilt or empathy in their actions and there is a massive difference between someone who feels bad about their actions and a person who simply does not care and feels zero guilt.

The question is, though, if you don’t feel guilty about your actions or have no remorse, does this mean your sleep is left undisturbed too? Well, the study hypothesized that these “callous” individuals would actually sleep better. As whether you have a mental illness like depression or simply find it difficult sleep – it is usually centred around anxiety we feel because we care – whether that be family troubles, work stress etc. It all surrounds our feelings. Whereas these “callous” people seem to have significantly less feelings that could disturb sleep.

In order to test their hypothesis, a study of 1,556 young adults took place that looked at sleep quality while also conducting surveys on their disruptive behaviour, unemotional traits, anxiety levels and callousness. And as they expected, it was found that those with low levels of unemotional traits and callousness, yet high levels of anxiety or disruptive behaviour would suffer from the poorest sleep.

However, participants who had disruptive behaviour but were also noted to lack guilt and empathy did not have the same level of disturbed sleep in comparison. Those who simply were found to have unemotional and/or callous traits did not seem to suffer from any poor sleep quality.

This study was then repeated with similar questions, yet this time the 338 participants were aged between 18 and 66, as well as certain participants having their sleep monitored by wrist devices. 

Here the study got the same results – that those who had disruptive behaviour but felt guilty about it, would report a bad sleep. However, when this sleep was measured on motion devices it reported a good sleep. The study could not give a reason for this strange result, although they did say that as only 43 out of the 338 participants had their sleep measured then this could be the reason.

The most interesting result found, though, was again people who were found to be both unemotional and callous slept great at night – both from the surveys and the sleep monitors.

So, next time you see someone and wonder “how does he/she sleep at night” then, most likely, if they are a terrible person then the answer is that they sleep incredibly well. In fact, they probably sleep better than you at night!

Image courtesy of imagerymajestic at