Objective: Prior longitudinal studies of negative working conditions and depression generally have used a single exposure indicator, such as job strain, and have required consistent availability of the measure across waves and selection of only those working at all measurement points.
Methods: Up to four waves of the Americans' Changing Lives study (1986 to 2001/2) and item-response theory (IRT) models were used to generate wave-specific measures of negative working conditions. Random-intercept linear mixed models assessed the association between the score and depressive symptoms.
Results: Adjusting for covariates, negative working conditions were associated with significantly greater depressive symptoms.
Conclusions: A summary score of negative working conditions allowed the use of all available working conditions measures and predicted depressive symptoms in a nationally representative sample of US workers observed for up to 15 years. Linear mixed models also allowed retention of intermittent workers.