from Yes! Magazine.
From my own experience in the Civil Rights and Anti-Vietnam War movements and beyond, I would add that these results are based on a limited time frame--the short run--and include rather benign forms of activism like writing a letter to your Congressman or voting. I do not believe that practicing such ordinary civil rights is activism. Excluding the latter, it is also true that activists have often, in the longer run, experienced severe burn-out resulting most dramatically in suicides (e.g. Phil Ochs), ruin of personal careers and financial security, FBI/police harassment, and jail time.
Serious activism should be undertaken with both eyes open and being informed. Making a difference can lead to feelings of well-being if one does, in fact, make a difference. As they say, "nothing succeeds like success". When people succeed, the effects can be an incredible psychological high unlike any that a drug can produce.
I've personally witnessed this among the people in Nicaragua when the Sandinista Revolution succeeded in the early 80s. Likewise when I visited four years later, I saw severe depression among those people when the US sponsored Contras managed to destabilize that country and turn back the changes that those people had fought and died for.
But like Mario Savio said in 1964 on the steps of Sproul Hall, UC Berkeley, "There is a time when the operation of the machine becomes so odious, makes you so sick at heart, you can't take part. And you've got to put your body upon the gears and upon the wheels, upon the levers, upon all the apparatus, and you've got to make it stop."
In order to enhance the chances of success, I would argue that it is of critical importance that people proceed by being informed as best they can. That means learning from the experience of those activists that have come before. It means discussing with others the theories and practice of social change. It means organizing with others of a like mind. It means a critical review of activities undertaken. I think it means that activists should choose goals that are reasonably possible given the resources at hand and the real conditions that exist. Ideally, it means having a theory, strategy, and tactics that are well thought out, agreed upon, and revised as people gain experience.