The predictive power of personality traits on insomnia symptoms: A longitudinal study of shift workers

Shift work can have adverse effects on employees' health, including by inducing symptoms of insomnia, which can cause severe problems for both employees and employers. The personality variables of morningness, neuroticism, and extraversion, along with some demographic variables, have been found to correlate with symptoms of insomnia, although predictive data remain scarce. In response, in this study we sought to discover whether personality variables could predict insomnia by conducting a hierarchical longitudinal (6-month) regression study with shift workers (n = 96) employed in the health or social sectors in Trondheim, Norway. We included age, gender, children at home, years of experience and shift schedule as variables in Block 1, and neuroticism, extraversion and morningness as variables in Block 2. As measured by the Bergen Insomnia scale, insomnia was set as the dependent variable. Among other results, neuroticism was positively predictive of insomnia at T2, in accordance with previous studies, whereas morningness was negatively related, which aligns with some research on the subject. Age was found to negatively relate to insomnia, which opposes previous findings. As such, some personality variables seem to predict insomnia among shift workers, although additional longitudinal studies with larger samples should be conducted to validate our results.