Thesis (Professional Doctorate) - La Trobe University, 2010
Abstract: This thesis investigated fatigue and mental health in paramedic shiftworkers. Previous studies have observed elevated fatigue and poor health in this sector from occupational demands and shiftwork rostering. Study-1 investigated 342 paramedics from the Metropolitan Ambulance Service in Melbourne, while Study-2 investigated 150 paramedics from Rural Ambulance Victoria and examined potential rural-urban differences. The Standard Shiftwork Index was administered to prospective participants in both cohorts who worked a rotating shiftwork roster. Single sample t-tests found significantly elevated indices of mental health, higher fatigue, significantly poorer sleep quality, and less physical activity than reference samples. Depression and sleep quality explained the greatest amount of variance in fatigue scores for both groups. No differences were detected in levels of depression or fatigue on the basis of gender. Findings suggested that both rural and urban ambulance paramedics could be at particular risk of elevated fatigue and depression (regardless of age or gender) and poor quality sleep. Organisational intervention was suggested for both studies. Study 3 proposed a theoretically derived path model of shiftwork aimed at elucidating those factors most likely to predict individual circadian differences in the combined samples. Circadian type and chronotype were tested as moderator variables, and mental health variables as mediators of sleep quality, fatigue, and longer-term physical health outcomes. A good to excellent fit of the model to the data was found, with substantial variances explained. While individual differences contributed some predictive value, the path coefficients were relatively small. Morning-types were largely absent from the sample, and evening typology was correlated with adverse health outcomes. Flexible-rigid typology was considered to confer some benefit in shiftworkers. The path model demonstrates the direct and indirect effects of mental health indices on other variables. The model also offers potential points of clinical intervention to address adverse health outcomes for these shiftworkers.
Submission note: "A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Clinical Psychology [to the] School of Psychological Science, Faculty of Science, Technology and Engineering, La Trobe University, Bundoora".
The thesis author retains all proprietary rights (such as copyright and patent rights) over the content of this thesis, and has granted La Trobe University permission to reproduce and communicate this version of the thesis.