Circadian misalignment in shift work and psychiatric outcomes: a narrative review

Shift work is a structural exposure that may influence psychiatric outcomes through misalignment between internal circadian timing and externally imposed work schedules. We synthesize psychiatric consequences, candidate mechanisms and clinically feasible intervention strategies. This narrative review integrates epidemiological, mechanistic and clinical evidence on shift work, circadian misalignment, shift work disorder (SWD) and psychiatric outcomes, with emphasis on meta-analyses, prospective cohorts, experimental circadian studies and clinically informative intervention research. Across study designs, shift work is associated with small-to-moderate elevations in depressive and anxiety outcomes, with variability partly driven by heterogeneous exposure definitions. Findings are best interpreted within an “exposure load × individual vulnerability” framework: higher night-shift frequency, quick returns (<11 h), consecutive nights and rotation patterns contribute to exposure load, whereas chronotype mismatch and an SWD phenotype mark vulnerability. Circadian misalignment, curtailed sleep opportunity and psychosocial burden may function as mediating and, in some contexts, moderating pathways. Evidence on cognitive performance and suicidality is more heterogeneous but suggests meaningful high-risk subgroups under high exposure load. Management should not rely on a single intervention. A layered strategy—combining behavioral and light-based measures, selected chronobiotic or wake-promoting approaches, and organizational redesign—should be stratified according to exposure load and individual vulnerability.