Theoretical model of the mediating role of psychological capital on the association between occupational stress and depressive symptoms. c: associations of extrinsic effort, reward or overcommitment with emotional exhaustion, depersonalisation or personal accomplishment; a: associations of extrinsic effort, reward or overcommitment with PsyCap; b: association between PsyCap and emotional exhaustion, depersonalisation or personal accomplishment after controlling for the predictor variables; c’: associations of extrinsic effort, reward or overcommitment with emotional exhaustion, depersonalisation or personal accomplishment after adding PsyCap as a mediator.