World leaders currently making tough economic decisions should be guided by the physicians' mantra: “First, do no harm”. Austerity programmes, even if justifiable in terms of promoting growth (itself highly questionable), may exacerbate the health risks posed by financial crises.

Inflicting short-term pain constitutes a massive, uncontrolled experiment with people's lives. Recessions themselves pose a risk to health, but empirical data reveal that the decisions made by governments crucially determine how bad the outcome will be.

To mitigate the effects of the Great Depression in the 1930s, US policy-makers created a social-welfare system and invested in public-health programmes. Mortality rates fell by about 10%, mainly owing to a decrease in infectious diseases and road-traffic accidents (P. Fishback et al. Rev. Econ. Stat. 89, 1–14; 2007).

But in several eastern European countries after the economic collapse of the early 1990s, policy-makers massively cut social and health budgets, while deregulating the economy. Mortality rates rose by about 40%, mainly through heart attack, stroke, alcohol-related death, suicide and homicide. There were more than 3 million excess deaths (D. S. et al. Lancet 373, 399–407; 2009) — the worst peacetime mortality crisis in the past half-century.

European Union (EU) mortality trends during recessions in the past three decades indicate that member states can avoid a rise in suicide rates by spending US$200 per capita a year or more on labour-market programmes, designed to improve people's chances of gaining employment (D. S. et al. Lancet 374, 315–323; 2009). In those spending less than $70 — such as Spain and the mainly eastern European countries that joined from 2004 onwards — a deteriorating economy correlates with a rise in suicide rate. But in Finland and Sweden, which spend at least $300, economic change has no discernible short-term effect on overall population health.

What can scientists do to help protect public health in times of economic crisis? They should promote an evidence-based approach to economic and public-health recovery, analysing past successes and failures. This will lead to a better understanding of why some people, households, communities and societies are resilient to external shocks.