Not an SSRI, but similar - I was on an SNRI (Cymbalta) for 6 months coming out of a nearly fatal bout of asthma. Basically I was depressed because I was constantly scared of dying and still felt unable to breathe despite all objective tests indicating otherwise after successful treatment. Anyway, the Cymbalta worked and I felt great for the first 3 months, but then I slumped into the worst pit of depression and suicidal ideation hell I had ever experienced. Even my personality and sexual preferences changed. One day I decided to just quit it cold turkey, and for the next 2-3 weeks I had non-stop brain zaps. Eventually they stopped and I was back to normal. My doctor wanted me to continue and increase the dose, which would have been absolute insanity. I learned later that Cymbalta had a black box warning for suicidal ideation. Fun times.
> I learned later that Cymbalta had a black box warning for suicidal ideation
Most of the drugs that alter neurotransmitters (ADHD and depression meds, some seizure meds) will have a warning for suicidal ideation that may occur at some point of the treatment (usually early on). It's a balancing act between the treatment and the "illness" and has to be taken with caution.
Almost every doctor or psychiatrist I've seen or my family members have seen usually start off too strong and in many cases will advise cutting cold turkey. I always ignore it and taper on slowly over for about a month and if I need to get off the meds, I taper off slowly over 1-2 months. I was on Zoloft for 10 years and I was able to successfully got off the drug with minimal side effects that way. Although there was definitely a short period of brain zaps near the end, it wasn't as bad as the usual kind I'd get if I forgot to take the meds for a couple of days.
EDIT: If you use the taper off method, make sure to understand the half-life/how long it stays in your system.