I think antidepressants can help people, however I believe they only provide symptomatic relief. This can be vital to get through difficult times, and can help relieve the depression to the stage where you can take action to improve things for yourself, finds ways of accepting your situation and getting something from life anyway, or often a combination of both of these things.
You need to be diagnosed and prescribed by a professional, if you can find a compassion doctor that cares and attempts to understand your situation and needs all the better.
They can take up to 4-6 weeks to gain a full effect, however some research suggests newer medications such as lexapro can take effect as quickly as two weeks.
good luck