Since 2021 the UK has experienced a sharp rise in inflation. For many, wages and welfare payments have not kept up with rising costs, leading to a cost of living crisis. There is evidence indicating that economic crises are damaging to population mental health and that some groups are particularly vulnerable. The review aims to 1. Identify and appraise available population level measures and methods for assessing the impact on mental health of any public health response to the cost of living crisis, and 2. review the appropriateness of the measures for specific, vulnerable populations. Study designs and mental health measurement tools: These included secondary analyses of existing data, household panel surveys, repeated cross-sectional surveys; or used routine clinical data including medical records, prescribing data, or were ecological time-series studies using national or regional suicide death rates. 12 validated mental health measurement tools were identified. Four validated mental health measurement tools are embedded into UK population-level surveys. Vulnerable groups: 11 mental health measurement tools were used to identify population sub-groups whose mental health was most likely to be affected by an economic crisis. There is evidence that the mental health measurement tools and methods are suitable for measuring mental health in people with different socio-economic and financial situations. It was not possible to determine whether the methods and tools effectively captured data from people from minority ethnic groups. Policy and practice implications: Many UK population-level surveys, include validated mental health tools and questions about financial security, providing data that can be used to explore population mental health. A quasi-experimental study design, using data from a household panel could be suitable for measuring the mental health impact of a specific public health initiative to tackle cost of living pressures. Reports and studies using population-level surveys or medical records should present data on ethnicity and, where possible, plan to stratify analyses by ethnicity. Economic considerations: Poorer households are more exposed to inflationary pressures. In the lead up to the cost of living crisis, Wales had the highest proportion of working age adults and pensioners in relative income poverty out of the UK nations. 28% of children in Wales were living in relative poverty. Given that over half of all mental health problems start by age 14 (and 75% by age 18) and poverty being a risk factor for psychological illnesses, there is likely to be a long shadow of mental health continuing into future generations stemming from the cost-of-living crisis. Mental Health problems cost the Welsh economy 4.8 billion (UK pounds) per annum. In a recent survey of Welsh participants, 60% of respondents agreed that rising costs of living negatively affected their quality of life.