This study examines the relationship between the personality traits of Neuroticism and Extroversion and sleep patterns and others sleep behaviours in medical students.

Neuroticism and Extroversion were assessed using the Portuguese version of the Eysenck Personality Inventory. Sleep was assessed with a self-response questionnaire covering a wide range of sleep-wake habits and difficulties. A factor analysis with varimax rotation was performed with seventeen items of the questionnaire and four factors were extracted: Sleep Disturbance, Sleep Timing, Insufficient Sleep and Dreams/Nightmares. A total of 203 third year medical students (127 females, 62.6%) mean age 20.01 (SD=1.09; Range=18-24) participated in the study.

There were no significant gender differences in Neuroticism and Extroversion mean scores (Neuroticism: p=.454; Extroversion: p=.891). Extroversion was significantly correlated with Sleep Timing (p=.000), whereasthere was a trend for Neuroticism to be associated with Sleep Disturbance (p=.095). Concerning the relationship of Neuroticism and Extroversion mean scores with other Sleep problems, Neuroticism was found associated with concentration difficulties in the morning (p=.006), inadequate sleep duration (p=.001), sleep problems (p=.012), and use of sleep medication (p=.052). No significant associations were found with Extroversion.

Neuroticism was significantly associated with sleep problems, use of sleep medication, inadequate sleep duration, and concentration difficulties in the morning. Extroversion was correlated only with later Sleep Timing.