INTRODUCTION The aim of this study was to investigate how the dynamics of the social environment impacted the alcohol consumption of individuals who self-identified as heavy drinkers.

METHODS A mixed methods approach including N-of-1 study with daily Ecological Momentary Assessment (EMA) followed by a social network egonet interview. Qualitative data was analysed using deductive and inductive approaches. The main quantitative outcomes were a number of social contacts and the supportiveness of social networks.

RESULTS Fifteen participants provided sufficient EMA data regarding social contact and six of these took part in the egonet interviews. EMA respondents reported 10.8 social contacts on average and rated approximately half of their networks as positive supports; approximately 10% of each respondents' networks were perceived as 'drinking a lot'. Interview data illustrated the influence of peer and family networks; stress; motivation levels; and coping strategies within the context of the social world. EMA and egonet methods proved feasible with this specific population demonstrating the utility of innovative approaches to study dynamic social contexts related to substance use.

DISCUSSION Respondents either drew upon their social resources and implemented strategies to support behaviour change or experienced social strain and poor mental health in the absence of supportive social strategies. Future research should explore how social networks can impact maintaining non-drinking status and accessing supports. Mixed methods research combining N-of-1, EMA, and egonets can provide novel insights into social dynamics.