While standard epidemic models are well established in the mathematical modelling of infectious disease, the application of these techniques into other complex spreading processes that occur among society (e.g. opinions, behaviours) is becoming more routine. Improving our understanding of the social processes that drive the epidemiology of mood disorders, such as depression, has the potential to bring about highly significant public health benefits.

In this project we looked at the way teenagers influenced each others’ mood in a group of US high schools. We found that while depression does not ‘spread’, having enough friends with healthy mood can halve the probability of developing, or double the probability of recovering from, depression over a 6-12 month period. These results suggest that promotion of any friendship between adolescents can reduce depression since having depressed friends does not put them at risk, but having healthy friends is both protective and curative.

This work was carried out as part of my Ph.D. studies in conjunction with Thomas House , Frances Griffiths and Robert Eyre.

A downloadable PDF of my thesis entitled "Mathematical modelling approaches for spreading processes : zoonotic influenza and social contagion" can be found here.

Relevant Publications

• Modelling the Spread of Mood. In: Mood: Interdisciplinary Perspectives, New Theories.
  Edward M. Hill and Thomas House (2019) pp. 87-108.
  Volume editors: Birgit Breidenbach and Thomas Docherty. doi:10.4324/9780429259432
• Spreading of components of mood in adolescent social networks 
  Robert W. Eyre, Thomas House, Edward M. Hill, Frances E. Griffiths (2017)
  Royal Society Open Science, 4: 170336. doi:10.1098/rsos.170336
• Spreading of healthy mood in adolescent social networks 
  Edward M. Hill, Frances E. Griffiths and Thomas House (2015)
  Proceedings of the Royal Society B, 282(1813). doi:10.1098/rspb.2015.1180.