# A Closer Look at the Sleep/Wake Habits and Dark Triad Traits
## 3 Results  
The mean and SD of the items of the MCTQ were as follows: bedtime prior to free days (00:21 \(\pm\) 1:31 h), bedtime on workdays (23:11 \(\pm\) 1:12 h), wake time on free days (9:16 \(\pm\) 1:34 h), and wake time on workdays (7:23 \(\pm\) 1:06 h).  
In the next step, we calculated the correlations between the DT traits and sleep variables. There was a positive relationship between the Dark Triad composite and eveningness (r = 0.15), and a negative relationship between the DT and circadian distinctness (r = \(-\)0.15) was observed.  
Regarding Machiavellianism, some significant positive relationships emerged with pediatric daytime sleepiness, later bedtimes and wake times on working and free days, and more frequent sleep disturbances. Machiavellianism showed a negative relationship with circadian distinctness (r = \(-\)0.08)  
Psychopathy appeared to be positively correlated with sleep and wake-up time instability, later bedtimes and wake times on working and free days, and more frequent experiences of sleep disturbances and eveningness (r = 0.19). On the other side, psychopathy was negatively linked with morningness (r = \(-\)0.14)  
Narcissism was only negatively associated with pediatric daytime sleepiness and circadian distinctness (r = \(-\)0.19); none of the DT traits were correlated with subjective sleep quality. The results are depicted in Table 1.  
Later, we ran a series of regression analyses to see to what extent the DT traits together might predict the linked sleep variables. Except for pediatric daytime sleepiness, narcissism was removed from the analysis for being unrelated to sleep variables. Machiavellianism and psychopathy together predicted 3.8% of the variance of bedtime prior to free days followed by wake-up time on free days (3.4%), bedtime on working days (2.5%), sleep disturbances (1.2%), and wake-up time on weekdays (1.1%). Additionally, narcissism, with the other two DT traits, predicted 3.6% of the shared variance of pediatric daytime sleepiness. The results are presented in Table 2.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **M** & **N** & **P** \\ \hline Subjective sleep quality & \(-\)0.01 & 0.06 & \(-\)0.05 \\ \(p\) & 0.70 & 0.13 & 0.19 \\ Sleep timing instability & 0.02 & 0.01 & 0.18 ** \\ \(p\) & 0.58 & 0.78 & \textless{}0.01 \\ Wake-up timing instability & 0.05 & 0.02 & 0.13 ** \\ \(p\) & 0.21 & 0.52 & \textless{}0.01 \\ Pediatric daytime sleepiness & 0.09 * & \textless{}0.08 * & 0.14 ** \\ \(p\) & 0.03 & 0.03 & \textless{}0.01 \\ Bedtime prior to free days & 0.13 ** & 0.02 & 0.20 ** \\ \(p\) & \textless{}0.01 & 0.60 & \textless{}0.01 \\ Bedtime on workdays & 0.10 * & 0.02 & 0.17 ** \\ \(p\) & 0.01 & 0.53 & \textless{}0.01 \\ Wake-up time on free days & 0.14 ** & \textless{}0.02 & 0.18 ** \\ \(p\) & \textless{}0.01 & 0.63 & \textless{}0.01 \\ Wake-up time on workdays & 0.08 * & 0.00 & 0.11 ** \\ \(p\) & 0.04 & 0.84 & \textless{}0.01 \\ Sleep disturbances & 0.11 ** & 0.03 & 0.10 * \\ \(p\) & 0.04 & 0.84 & \textless{}0.01 \\ \hline \hline \end{tabular} Abbreviations: M: Machiavellianism, P: psychopathy, and N: narcissism. * \(p\) < 0.05; ** indicates \(p\) < 0.01.  
\end{table}
Table 1: The relationship between Dark Triad traits and sleep variables.