@Graphista I’ve taken paroxetine before for post natal ocd (twice, liked it enough to go back for more!). I’ll start with the positives 
it helped SO MUCH with the ocd, a couple of weeks in it was honestly like a switch flicked and all the things that had worried me just seemed ridiculous.
Things like making the baby’s bottle, which used to take ages of making and remaking and re-sterilising as I was convinced if I touched it I would poison him, suddenly became easy. I started enjoying cooking and going out without thinking I was making terrible decisions that would kill people. I also started being able to laugh, and hadn’t realised until then that I’d stopped. I honestly felt joyful and like myself again, and didn’t panic, overthink or need to do rituals any more. It literally saved my mental health as I was getting to a pretty bad place.
I also felt a tiny tiny bit stoned all of the time which wasn’t a downside for me 
but your mileage may vary!
I didn’t feel many downsides at all. I didn’t get diarrhoea, didn’t feel overly drowsy, but did get to sleep much quicker. No problems waking up in the night if ds needed me.
I did start having really lucid dreams though, which wasn’t a huge problem once I was used to them. I also got “brain zaps” a few times, like a quick flash of light in the corner of my eye plus a “zap” in my brain. I can’t explain it very well, but it only happened a few times.
The only time it affected me negatively was when I came off it, (as thisimmortalcurl said, it can be difficult with this particular drug) and that’s because my doctor messed up. I fell pregnant unexpectedly while taking it, informed my doctor who told me to immediately stop the paroxetine. That’s the worst possible advice as it can have quite bad consequences mentally and physically. Luckily I just threw up constantly for 2/3 weeks, which could well have been morning sickness, then felt very “heavy” and wobbly for a few weeks more. The second time I took it and decided to come off it, my gp made a plan for tapering the dose off little by little and I had no side effects at all coming off it.
Tl:dr - no diarrhoea, little bit stoned in a nice way, watch out for the weird dreams, make sure you taper off.
Good luck, I hope it helps. Ocd is an unrelenting bastard. 