although im not an expert on this, im pretty much certain it would cause you major problems, especially if you did not bring this up a.s.a.p because then it would be apparent you had lied/covered up about dependancy and depression and youd have no chance.
ask your doctor It sounds like he is qualified to give you this answer, otherwise seek proper help and not from a forum (without some genuine history and reason) or you could be in for a bit of a shalaking
I think you would be defered, but it depends on how long ago it was. I had my letter back last week from the M.O and i've been defered untill Aug this year. My depression entry was last year due to a close family death and marraige problems, and i had on my records medication untill aug 07, even though i didn't take them all, its on my records. They will evaluate each case as they see it, but the fact you said you were dependant on achol won't look good. My advice is to put it all down on your R8 form, go and see the doctor when he fills in his part and see if he could add some nice notes explaining the situation, but i can't see you will be excluded to join.
Good luck and keep us posted, your story could help other people so its always good to stay in touch.