Social determinants of depression among mid-to-older aged Australians: A prospective study of the effects of neighbourhood disadvantage and crime.

Background: Few studies examining social determinants of depression have incorporated area level objectively measured crime combined with self-report measures of perceived crime. How these factors may interrelate with neighbourhood disadvantage is not well understood, particularly in Australia, where mental health disorders are of major concern. This study examined relationships between area-level objective crime, self-reported perceptions of crime, neighbourhood disadvantage and depression, and potential mechanisms by which these variables indirectly lead to depression. Methods: This study used data from the HABITAT Project, a representative longitudinal study of persons aged 40-65 years residing in 200 neighbourhoods in Brisbane, Australia, during 2007-2016. A prospective sample of residentially stable persons who reported depression at two years (n =3120) and five years (n=2249) post-follow-up was developed. Area level objective crimes were categorised as either crimes against the person, social incivilities or unlawful entry. Logistic regression was used to establish relationships with depression, followed by a decomposition analysis to establish potential mechanisms. Results: Neighbourhoods in the highest quartile of crimes against the person had an increased risk of individuals reporting depression at all periods of follow-up. Associations were also found between unlawful entry and depression. Decomposition analysis indicated a positive and significant total effect of crime against the person on depression for all periods of follow-up, while an indirect effect of perceived crime was found to partially explain this relationship at 2-years after baseline (prop. Mediated = 46.5%), and at either or both periods of follow-up (prop. Mediated = 53.7%), but not at 5-years follow-up. Discussion: Neighbourhoods with the highest levels of crime against the person may influence depression over time through a pathway of perceived crime. Perceived crime, particularly in areas of high crime against the person should be considered as part of a multi-faceted strategy aimed at improving population mental health.