A . Evidence for joint planning and preventative spend across community planning (Prevention model)
There is plausible theory from review-level evidence and Scottish specific reports to support the link between preventative spend, tackling poverty and inequality to prevent problem drug use by enhancing life chances.
In a briefing to the Financial Scrutiny Unit (2010), preventative spend is defined by Scottish Parliament Information Centre as ‘public spending over the longer term that aims to prevent rather than deal with negative social outcomes’ .
An evidence review conducted by David Best and colleagues (2010) following publication of the national drug strategy highlighted the strong link between problem drug use and deprivation, suggesting that tackling deprivation, poverty and widening inequalities (for example in housing and employment) could have a positive impact on prevention and recovery. 
Based on Sally MacIntyre’s framework of guiding principles for effective policies and interventions to address health inequalities for the 2008 Ministerial Task Force, interventions assessed as most likely to have some impact on health inequalities include action on the social determinants of health; structural changes in the environment; legislative and regulatory controls; fiscal policies; income support; reducing price barriers; improving accessibility of services; prioritising disadvantage; offering intensive support, and starting young. 
The theory of causation presented in NHS Health Scotland’s Health Inequalities Policy Review for the Scottish Ministerial Task Force on Health Inequalities articulates clearly how inequalities arise. Given the established vulnerabilities associated with problematic drug use encountered through the experience of deprivation and poverty, the theory of causation further identifies how wider (economic, physical, learning, services, social and cultural) environmental influences impact on individual experience of disadvantage, creating less of a choice and more a response to these wider factors.
The Health Inequalities Policy Review states ‘Physical and social environments shape the options available to individuals and choices they take, meaning that even “lifestyle” factors have to be interpreted on the basis of the contexts in which they arise.’ (2014, p. 24). Thus, the ability of individuals and families to live in ways that create and sustain health is influenced by factors largely beyond their control. Action so far has largely been to mitigate the consequences of inequalities.
The Health Inequalities Policy Review draws on conclusions from the Christie report Commission on the future delivery of public services (2011), the Scottish Parliament Finance Committee Report on Preventative Spend (2010) and the Audit Scotland report Health Inequalities in Scotland (2012) to emphasise the importance of preventative spend both as a means of reducing the potential future demands on health and social care and as a means of tackling health inequalities. 
Scottish policy and practice note
The Scottish Government national drugs strategy, The Road to Recovery: a new approach to tackling Scotland’s drugs problem (2008)  highlights the Government’s economic strategy as a means to increase sustained economic growth, to be achieved through improving learning; skills; wellbeing; creating supportive business environments; developing infrastructure and greater equity through a closer more effective partnership between central and local government.
Drawing from Equally Well (2008) this is further highlighted in NHS Health Scotland’s Health Inequalities Policy Review for the Scottish Ministerial Task Force on Health Inequalities (2014). The review affirms that achieving better joint working across agencies and services as well as involving local communities and target groups are seen as the cornerstones for successful delivery on health inequalities. The policy review states that these principles are embedded in the Equally Well report (2008) and the Review of Community Planning in 2012, as well in recommendations from the Christie Commission (2011) – the report on the Future Delivery of Public Services by the Commission. The policy review further articulates a need to shift focus away from meeting the cost of dealing with health and social problems after they have developed to prevention and early intervention.
The Early Years Framework (2009)  focuses on building parenting and family capacity, creating communities that support the positive development of children, delivering integrated services that meet children’s holistic needs and developing a workforce to deliver this. The Early Years Framework defines early years as pre-birth to eight years old in recognition of the importance of pregnancy in influencing health, social, emotional and cognitive outcomes for children and families. The framework, which is based on principles of early intervention and the tailored delivery of services, outlines the steps that the Scottish Government, local partners, and practitioners in early years services need to take to maximise positive opportunities for children so that they get the best start in life.