Objective This study aimed to investigate the association between individual and psychosocial work factors and mental distress among offshore shift workers in the Norwegian petroleum industry.

Methods All 2406 employees of a large Norwegian oil and gas company, who worked offshore during a two-week period in August 2006, were invited to participate in the web-based survey. Completed questionnaires were received from 1336 employees (56% response rate). The outcome variable was mental distress, assessed with a shortened version of the Hopkins Symptom Checklist (HSCL-5). The following individual factors were adjusted for: age, gender, marital status, and shift work locus of control. Psychosocial work factors included: night work, demands, control and support, and shift work–home interference.

Results The level of mental distress was higher among men than women. In the adjusted regression model, the following were associated with mental distress: (i) high scores on quantitative demands, (ii) low level of support, and (iii) high level of shift work–home interference. Psychosocial work factors explained 76% of the total explained variance (adjusted R^²=0.21) in the final adjusted model.

Conclusions Psychosocial work factors, such as quantitative demands, support, and shift work–home interference were independently associated with mental distress. Shift schedules were only univariately associated with mental distress.

Key terms individual work factor; mental disorder; mental distress; mental health; neuroticism; night work; Norway; petroleum industry; psychosocial work factor; shift work; shift work locus of control; shift work–home interference