answer:Here’s the Mayo Clinic’s explainiation, which is pretty good:
http://www.mayoclinic.org/diseases-conditions/depression/expert-answers/antidepressants-and-alcohol/faq-20058231 In general alcohol is a Central Nervous System (CNS) depressant. This is not the same as the disorder Depression, but what it does is slow down your nervous system, essentially, and in a very general way. Having two different drugs, one targeted and one general, affecting your nervous system is a tricky problem. Two targeted drugs can many times be okay, but even that a doctor needs to look at and check. A general drug like alcohol just tends to wreck havok. Specific to SSRIs, just looking at a list of potential side effects I can tell you why it may not be a good idea: drowsyness, nausia, headache (from a hangover or before), weight gain, vomitting, and dizziness are all potential side effects shared between alcohol and SSRIs. Taking both drugs has a chance to severely increase the intensity, or make side effects appear when you weren’t experiencing them before. For instance, my gf used to not get hangovers, now that she’s on SSRIs if she drinks one or two drinks even, she gets really bad ones. Your milage can and almost certainly will vary, but the risks are there. Now, if you want the real scientific mechanisms behind all of this it’ll take more digging, but I can look if you’re interested.