The doctor recommended I start off on a half-dosage so that any side-effects are mild. The SSRI in question is Sertraline, and the usual dosage is 50mg a day, so these last four days I've just been on 25mg instead. I haven't noticed anything different other than being more aware of my lower-jaw and so clenching my teeth every now and then (grinding teeth is one of the usual side-effects, apparently). I've also noticed I can keep my contact lenses (dailies) in for a lot longer than usual before my eyes feel tired, but I'm pretty sure that's unrelated :P Will move up to 50mg as of tomorrow. Will see what happens.