Is Night Shift Work Associated With Depression and Suicidal Ideation? A 17-Year Follow-Up Study

Despite awareness of night shift work's mental health risks, its long-term effects, especially sex differences, remain underexplored. The aim of the study was to investigate the association between night shift work and mental health outcomes using multivariable regression models and to assess sex differences in these associations.

We analyzed data from 9,057 participants (mean age = 22.08 years, 52.6% females) who participated in Waves III (2001-2002), IV (2008-2009), and V (2016-2018) of the National Longitudinal Study of Adolescent Health (Add Health) in the USA. Associations between night shift work and mental health outcomes were assessed using binomial generalized linear models to estimate relative risks (RR; 95% CIs). We tested night shift with sex interactions and performed sex-stratified analyses when significant.

Night shift work for 17 years (4.6% of the participants), was associated with an increased risk of suicidal ideation (RR = 2.30, 95% CI [1.35, 3.90]) and depression (RR = 1.46, 95% CI [1.02, 2.09]) in women, but not in men. Depressive symptoms including feeling unhappy (RR = 1.69, 95% CI [1.15, 2.46]) and "shake blue/feeling blue" (RR = 2.04, 95% CI [1.01, 4.12]) were significantly associated with night shift work in men. In women, feeling sad (RR = 1.79, 95% CI [1.05, 3.07]) and "shake blue/feeling blue" (RR = 1.87, 95% CI [1.02, 3.43]) were also significantly linked to night shift work.

Long-term night shift work was associated with suicidal ideation and depression among women, but not men, reflecting sex-specific susceptibility to adverse mental health outcomes. Our findings suggest the need for sex-specific interventions to address the mental health risks of night shift work, particularly in women.