Objective To analyse a simplified model of psychosocial work environment in order to estimate how changes over time in factors related to psychological working conditions, work-life interface and personal characteristics influence workers well-being trajectory.

Methods The simplified model, which includes working conditions (Job Demands, Job Control, Supervisor Support and Co-workers Support), Work-Family Conflict (Conflict based on Strain and Conflict based on Time) and Sense of Coherence, was examined in a three time points longitudinal survey including 1691 workers using latent growth curves models (LGCM) with time-varying effects through a structural equations modelling approach.

Results Group level individual trajectories of Time-Varying Covariates (TVC) showed that Job Demands and Time-based Conflict decreased, Co-Workers Support increased and Supervisor Support remained stable. Only Time-based Conflict and Supervisor Support showed individual workers variation across change. Job Control and Sense of Coherence individual trajectories had no acceptable fit to the data. Well-being trajectory showed a significantly increase over time and this growth was conditioned significantly by Job Demands, Time-based Conflict and Sense of Coherence in the three moments, by Job Control and Supervisor Support in two moments, but not by Co-Workers Support time-specific effects.

Conclusions Working environment factors have differentiated intervention regardless of their isolated trajectories in a dynamic compatible with a systemic mechanism of homeostatic and adaptive type, with the ability to activate resources necessary to maintain the highest possible Well-Being level.

Knowledge of this adaptive dynamics is a critical issue to the adoption of company’s policies favourable to employees Well-Being and individual resources improvement.