Research Dynamic spread of... Dynamic spread of happiness in a large social network: longitudinal analysis over 20 years in the Framingham Heart Study Research Dynamic spread of happiness in a large social network: longitudinal analysis over 20 years in the Framingham Heart Study BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.a2338 (Published 05 December 2008) Cite this as: BMJ 2008;337:a2338 Jame