The economic crisis in Europe and North America led to more than 10,000 extra suicides, according to figures from UK researchers.
A study, published in the British Journal of Psychiatry, showed "suicides have risen markedly".
The research group said some deaths may have been avoidable as some countries showed no increase in suicide rate.
Campaign groups said the findings showed how important good mental health services were.
The study by the University of Oxford and the London School of Hygiene & Tropical Medicine analysed data from 24 EU countries, the US and Canada.
Unemployment, repossessions and debt
It said suicides had been declining in Europe until 2007. By 2009 there was a 6.5% increase, a level that was sustained until 2011.
It was the equivalent of 7,950 more suicides than would have been expected if previous trends continued, the research group said.
Deaths by suicide were also falling in Canada, but there was a marked increase when the recession took hold in 2008, leading to 240 more suicides.
The number of people taking their own life was already increasing in the US, but the rate "accelerated" with the economic crisis, leading to 4,750 additional deaths.
The report said losing a job, having a home repossessed and being in debt were the main risk factors.
However, some countries bucked the trend. Sweden, Finland and Austria all avoided increases in the suicide rate during the recession.
One of the researchers, Dr Aaron Reeves, of the University of Oxford, said: "A critical question for policy and psychiatric practice is whether suicide rises are inevitable."
'Policy potentially matters'
He told the BBC: "There's a lot of good evidence showing recessions lead to rising suicides, but what is surprising is this hasn't happened everywhere - Austria, Sweden and Finland.
"It shows policy potentially matters. One of the features of these countries is they invest in schemes that help people return to work, such as training, advice and even subsidised wages.
"There are always hard choices to make in a recession, but for me one of the things government does is provide support and protection for vulnerable groups - these services help people who are bearing the brunt of an economic crisis."
Andy Bell, of the Centre for Mental Health, said: "The study says what we feared for some time: that unemployment, job insecurity and many other factors associated with the recession are associated with poor mental health and suicide.
"It reminds us how important it is to respond to that need and take preventative action where we can, and that primary care is properly resourced and able to identify people who are at risk."
Beth Murphy, of the charity Mind, said: "Since 2008, we've seen an increasing number of people contact the Mind Infoline concerned about the impact of money and unemployment on their mental health.
"Redundancy and other life circumstances brought about by the recession can trigger depression, anxiety and suicidal thoughts for anyone, whether they have previously experienced a mental health problem or not.
"For some people, these factors can become so difficult to cope with that suicide may feel like the only option."