This is an Accepted Manuscript of an article published by Taylor & Francis in Applied Economics on 26/04/2015, available online: http://www.tandfonline.com/doi/full/10.1080/00036846.2015.1021456.International audienceMacroeconomic dynamics are characterized by alternating patterns of periods of relative stability and large swings. Standard micro-founded macro-economic models account for these patterns through exogenous and persistent shocks. In this paper, we develop a fully decentralized and micro-founded macro-economic agent-based model, augmented with an opinion model, which produces endogenous waves of pessimism and optimism that feed back into firms' leverage and households' precautionary saving behaviour. A major emergent property of ...