Catherine Rampell reports on the research here. Part of her summary is this:
The paper is based on German survey data and finds that self-reported “life-satisfaction” increases by around 0.3 points on a scale from 0 to 10 for people who transition from unemployment to retirement. That’s about twice the increase in happiness that newlyweds experience. The average person who transitions from employment to retirement, on the other hand, does not experience a bump in life satisfaction.
Rather ironically, it is hope that keeps people unhappy while unemployed…