In this second and final part of this series about mental health commissions, we consider the extent to which it is possible to find hard evidence that these new structures really can drive mental health reform. Four key domains of improvement are established for the purposes of this review: do commissions lead to better resources, better services, better accountability and better stakeholder engagement? A review of the evidence from both Australia and overseas is presented. The article also considers how the commissions, federal and state, will organise their relationships productively to avoid duplication and promote synergy. What of those jurisdictions without commissions? Is this genuine national reform or merely more piecemeal activity in mental health? The authors have been informed by the varying structures and functions of mental health commissions internationally and were part of the New South Wales taskforce to establish a mental health commission. They had the opportunity to visit the Western Australian and New Zealand Commissions as part of this process. CONCLUSION: Addressing mental illness requires a joined up approach to government and services. Commissions offer a new organisational structure designed to deliver this contiguity. There is also evidence that nascent and established commissions are delivering real reforms, including in terms of additional resources and influence. Without concerted efforts to coordinate activity, the intersection between federal and state commissions will be confused and duplications might arise. The paper calls for a new network of commissions to be established across Australia and New Zealand, to share resources and common tasks, clarify roles and build common approaches.