Heroin in far worse physiologically, and
Paxil far worse emotionally to withdraw from. And
Paxil withdrawal can last a whole lot longer. But the reason it's not addictive is, to be technically considered addictive, you have to need to continually increase the dose to get the same effect. That's not true of ssris. But addiction is actually a medical term that has found it's way into our common lexicon in all kinds of erroneous ways.